PROSTHODONTICS

A patient has worn a complete maxillary denture for 8 years against mandibular anterior teeth. (the remainder of the mandibular teeth are missing) . She complains of looseness of the denture. Examination of the mouth shows an excessive amount of hyperplasatic tissue at the anterior part of the maxillary ridge. The maxillary denture teeth do not show below the upper lip. Radiographs show poor bone structure in the anterior part of the maxillae. The principle cause of difficulty with the maxillary denture is Fibrous tuberosities Too great a vertical dimension of occlusion A lack of posterior occlusion The maxillary denture teeth that were used are too short

A lack of posterior occlusion The patient's chiefcomplaint will be looseness ofthe maxillary denture. Thcy will also state thal they can no longer see their upper teeth on the denture. These signs and symptoms are caused by a lack of postcrior occlusion. Important: A patient wearing a maxillary complete denture and a mandibular bilateral distal-ex- tension removable partial may show: . Decreased vertical dimension ofocclusion . A prognathic facial appearance \ote: \\ftcn a complete maxillary dcnture opposes natural mandibular anterior tecth. the marillary tn- terior ridge often becomes very flabby. Rememberi The best impression technique for an edentulous patient with loose, h)?erplastic tissue in rhe maxillary anterior region is to register the tissue in its passive position. . 1. Denture support refe$ to rcsistance to vertical seating forces. )-oter,. *' 2. Denture stability is necessary to resist dislodgement of a dcnture in the horizontal direction. l. D"ntu." ."tertion is the ability ofthe denture to withstand dislodging forces exerted in the venical plane. Surfaces of a denture that play a part jn . Intimate contact ofthe denture base and its basal seat . Teeth: no occlusal prematurities to break rctention . retention: D€sign of the labial, buccal, and lingual polished surfices: configuration harmonious with forces generated by thc tongue and musculature 4. Factors that influence denture sudace: . . Adherion: saliva to denture and to tissues cohesion (the attraction ofmolecules lot -primary retentive force each other) depends onr the area covc.cd and the type of saliva . . /i.e. , thick, ropy -unfavorable; thin, \,atery - better retention) Atmosph€ric pressure: prcportionate to area covercd and depends on pe pheral seal Mechanical: ridge size, shape, and inter-ridge distance

You are ready to place packing cord around a tooth that was prepared for a crown on a patient with hypertension. You should use a cord impregnated with Epinephrine Alum (aluminum potassium sufate) Zinc chloride Any of the above

Alum (aluminum potassium sufate) Epinephrine causes local vasoconstriction, which in nrm results in transitory gingival shrinkage Epincphrine impregnat€d cord has been shown to produce minimal physiologic changes uhen placed in an intact gingival sulcus. Howeve( there is evidence ofincreased heart rate and elevated blood pressure when the cord is applied ro the severely lacerated gingival sulcus. For those patients with medical conditions such as certain tlpes of cardiovascular disease or hyperthy'roidism, or a kno\r'n hyPersensitivity to epinephrine, a cord impregnatcd with alum should be substituted. ,?ecrosis ofthe sulcular ePitheliu and the adjacenl lq:er ofconnecliv? lissre). Therefore, it should not be used in impregnatcd cord- Note: Zinc chforide is caustic and causes delay€d healiDg Tissue retraciion is necessrry to: . . . . Control bleeding Refiact the gingival tissues slightly away from the margins Allow imDression material to flow into the sulcus Expose all gingival margins Modes to achieve tissue displacement wh€n taking impressions: . . Mechanical modes lcdute.t - Cords: which stretch the circumferential periodontal fibers. They can be rwisled, braided, or knitted These cords can be impregnaled with chemicals such as aluminum, iron salts or epinephrine which cause transient ischemia and shrinkage ofthe gingival tissue, and absorb seepage ofgingival fluid They are supplied in different diametcrs. Surgical modes: - El€ctrosurgery: when cord will not produced the desired gingival displacement, this method can be used. Fluid control when taking impressions: . . M€chanical means: saliva ejectors, cotton rolls, cotton sponges Medications: anticholinergic drugs such as atropine. dicyclomine, glycopyrrolate, and methantheline act as anti-siafogogues f/educe salivary secrctiont. Notei Anticholinergic drugs should not be given to pa- iients with narrow-angl€ glaucoma. They should be used wilh caution in patients with heart disease.

Posterior teeth that are set edge to edge may cause Gagging Cheek biting Reduced taste Speech aberrations

Cheek biting l. Lip biting may be due to reduced muscle tone and/or a large anterior hori- zontal overlap. 2. Tongue biting may be caused by having posterior teeth too far lingually.

The filler in alginate gives the mixed material "body" that allows acceptable handling. Without filler the mixed material would be too runny for use. Which is the main component of alginate powder and functions as the filler? Zinc oxide Calcium sulfate Potassium titanium fluoride Diatomaceous earth (silica) Potassium alginate Tri-sodium phosphate

Diatomaceous earth (silica) (incversible h,vdt'ocolloid) are the most widely used impression materials. They are termed irreversible impression materials because they will not reverse Alginate materials to a sol once they react and become a gel. Indications: diagnostic casts, not suitable for final impressions. Examplcs: Ieltrate . Rapid set (Dentsply / Caulk), COE Alginare (GC America

Gypsum bonded investment material can be used for Dowel crowns to be cast in silver-palladium alloys Titanium crowns and copings The substrucfure for metal ceramlc crowns Type IV gold alloys None ofthe above All of the above

Dowel crowns to be cast in silver-palladium alloys Dowel cores do not require as much expansion as do crowns. So even though they are cast with Ag-Pd alloys (alloys that require a high temperature for expansion) gypsum bonded mold is used and heated to only 1200'F. Type I, II, and III Gold alloys can also be cast in g]?sum bonded investmen! material. The substructures for metal ceramic crowns ard Type IV Gold requires heating above 2100'F. These are invested in phosphate bonded material. Any alloy with a casting temperature in excess of 2100'F (115f" C) shouldbe cast in an invesfinent with a binder other than gypsum. High temperatures cause decomposition of calciurn sulfate in the gypsum binder with the resultant release ofcontaminating sulfur into the mold. Magnesium phosphcte reacts with primary ammonium phosphate to produce magnesium ammonium phosphate which gives the investment its strength at room temperature. At higher temperatures, silicophosphates are formed which give the investment its great strength. The metal-ceramic alloys must have a high melting range so that the metal is solid well above the porcelain baking temperatures to minimize distortion (sag) ofthe casting during porcelain procedures. A high sag factor will lead to distortion of bridge spans when the porcelain is fired. Remember: When casting a cedain alloy, make sure you use a crucible that has not been used for other allovs.

If mold that is created for investing and casting does not ? to compensate for the action of the metal alloy, the csting will not fit Equate Contract Expand None of the above

Expand Four mechanisms play a role in producing an expanded mold and thus compensating for the solidification shrinkage ofthe alloy. l. Setting expansion: results from normal crystal growth. In air, it is about 0.4% but it is partially restricted by the metal investment ring. 2. Hygroscopic €xpansion: employed to augment normal expansion by allowing the investment to set in the presence of water. It is said that this water will replace the water used by the hydration process and thus maintain the space between the growing crystals. Allows continued expansion outward rather than restricting them. This expansion ranges from 1.2%o to 2.2o/o. 3. Wax pattern expansion: the wax pattem is warmed while the investment is still fluid. The heat may come from the chemical reaction of the investment itselfor the s'ater bath in which the casting ring is immersed. 4. Thermal expansion: occurs when the investment is heated in the bum out oven. It also serves to eliminate the wax pattem and to prevent the alloy from solidifing be- fore it comoletelv fills the mold.

The incisal edges of the maxillary anterior teeth Linguoalveolar sounds or sibilants (such as s, z, sh, and ch) Fricatives or labiodental sounds (such as f, v, or ph) B, P, and M sounds Linguodental sounds (such as this, that, or those)

Fricatives or labiodental sounds (such as f, v, or ph) Speech sounds in the complet€ denture patlent: . Frictative or labiodental sounds (f, v, and ph): are formed between the maxillary inci- sors contacting the weVdry lip line of the mandibular lip. Note: These sounds help deter- mine the position ofthe incisal edges ofthe maxillary anterior teeth. j): arc made with the tip of the tongue and the most anterior part ofthe palate or lingual surface ofthe teeth. Note: These . Linguoalyeolar sounds or sibilants (s, z, sh, ch, and sounds help determine the vertical length and overlap ofthe antedor teeth. Important: A posterior dental arch form that is too narrow or high. whistling sound with dentures is indicative ofhaving a . Linguodental sou nds (this, that, and those,),' the tip of the tongue should protrude slightly between the maxillary and mandibular anterior teeth. Note: These sounds help determine the labiolingual position ofthe anterior teeth. . The b, p, and m solnds: are made by contact of the lips. Not€: Insuficient lip support by the teeth or the labial flange can affect the production ofthese sounds. Note: The two most probable causes of a patient complaining that whenever he/she tries to make an "s" sound. it sounds like "th" are: . . lncisor teeth are set too far palatally Palate is made too thick Important: To evaluate vertical dimension, have the patient pronounced the s sound; the in- terincisal sepantion should be I to 1.5 mm. This is known as the closest sp€aking space. Remember: . Ifthe teeth are positioned too far lingually, the "t" will tend to sound like a "d." Ifthe teeth are positioned too far labially, the "d" will sound more like a "t." . An increased occlusal vertical dimension can result in clicking ofteeth.

Which of the following landmarks is least relevant to the location of the posterior palatal seal area Pterygomaxillary notch Vibrating line Hamular process Fovea palatinae

Hamular process Landmarks for Posterior Palatal Seal . The posterior outline is formed by the "ah" $oove will form line or vibrating line and passes though the two pterygom xillary (hamrlay' notches and is close to the fovea palatini. . line and is located at the distal extent of the hard palate. The anterior outline is formed by the "trlow" Note: Excessive depth ofthe posterior palatal seal will usually result in unseating ofthe denture. Remember: The posterior palatal seal will vary in outline and depth according to the palatal form of the patient. Functions of the Posterior Palatal Seal: . . . . Completes the border seal ofthe maxillary denture Prevents impaction of food beneath the tissue surface of the denture Improves the physiologic retention of the denture Compensates for shrinkage of the denture resin during processing

When casting conventional gold alloys, which type of investment material is used? Silica-bonded investments Phosphate-bonded investments Gypsum-bonded investments

Gypsum-bonded investments A dental inyestment is a refractory material that is used to surround the wax pattern during the procedure of fabricating thc metallic p€rmanent restoration. It forms the mold into which the alloy is cast after the wax has been eliminated. An investment material to be used for a casting mold should expand on setting and heating to compensate for the shrinkage of molten metal as it solidifies. Metal casting alloys have diffcr- ent melting ranges -only pure metals and alloys of eutectic composition have a melting point. The melting range of gold casting alloys (aprox. 900'Q is lower than that of Co-Cr alloys (aprox. 1350'C), Therefore, investment materials used for gold casting alloys arc sometimes different from those used for Co-Cr alloys. The investment material should be ofa suitable consistency for adaptation to the wax model and have a reasonable setting time. To withstand the temperatures required for the casfing process there should be no distortion, no decomposition; thc investment should not fragment or disintegrate under the impact ofthe molten metal: the ma- terial should be porous to allow the escape ofair and gases and the investment should be easily removed from the casting after cooling. Classification of Dental Investment Materials . GJ-psum-bonded investments: binder is gypsum (calcium sulfate hemihydrate). Used' when casting conyentional gold alloys containing 65yo to 75y. gold at temperahrres near 1.100'c. . Phosphate-bonded investments: binder is a metallic oxide and a phosphate. Two lypes : Ti pe I is used when casting base metal alloys for rnetal-ceramic crowns and Type II is used for removable partial denhrre frameworks. Are capable of withstanding high temperatures /abote 1,100"C). . Silica-bonded investments: binder is ethyl silicate. Not used much today. The refractory material for thcse invcstments is either quartz or cristobalite. This material pro- lides the thermal expansion for the investment. Note: The expansion of the investment pro- vides a larger mold to compensate for the subsequent contraction ofthe alloy.

Which impression material has the best wettability Polyether Polysulfide Hydrocolloids (reversible and irreversible) Polyvinyl siloxane

Hydrocolloids (reversible and irreversible) Chart on page 78 has more info

According to the ADA classification for alloy systems used for metal-ceramic restorations, noble allovs: Have a noble metal content of > 60% Have a noble metal content of > 45% Have a noble metal content of > 25% Have a noble metal content of > 15%

Have a noble metal content of greater than or equal to 25% ADA classification for alloy systcms uscd for metal-ccrumic rcstontions . . . High noble alloys (old tem was pre.ious netal)t > 60o/n noblc rr'ctal contcnt (gold Nobfe alloys (o// ter"r, tr^r senripreciout metal): > 2570 noblc mclal contcnt Base metaf affoys foll ( o term was nonptecious metal): < 25y. notle fielzl conlent (tro god requile,l) Remember: Noble alloys (gold, plaainuD\ and > 40%) gold rcquircd) po adium) do not oxidize on casting. This featurc is important in a mctal substmte so that oxidation althc metel-porcehin interface can be controlledby thc addition oftracc clcmcnts to thc metal (silicon, ituiiun, and iridiunl . Desirable properties of alloys for metrl-cerrmic restorations: . High yield strength: minimizcs porcclain fracture duc to fmmcwork deformation pcrmancnt dcformation und$ occlusal forcc and . High modulus of elasti cilf (snfness)| minimizes flexure of long-span fixed bridgcs and to framcwork dcformation. . . Casting Nccuncy: basc mctal alloys arc lcss accuratc lban gold Biofogical compatibililf (for patient, dentist and lab technician): cat be a problcm with Nickcl and Bcryllium in base mctal alloys (a/&/gler/ . . Corrosion resistanc€ The metal coeflicient ofthermrl expansion should bc highcr than thc porcciain to lcavc thc prcsslon rn a stronSer statc )letal based based on color or composition: . . . . . \'ello* gold: > $hite gold: > Lo\n (econom\,) 60% gold content. 50% gold content. gold (usualr te ow): Higb prll.diurn whitc, mainly palladium, Sifler-pa lladi u m: whi te, silvet (5 < 600/0 gold (42yFs59/o) 5a/F7 I %o) Gold (22,/, littlc coppcr or cobalt , porcelain fracturc duc palladium for nobi lity and control ling tamish (2J%- 27/o) may or ma) not contain a little gold or copper . Pelladium-silver: whitc, mainly palladium, Porcclain adhercs to mctal silvcr up to 40%, - primarily by a chemical bond, A covalent bond is cstablished by sha;ng 02 with thc cl- cmcnts prcscnt in thc porcelain and the mctal alloy. These clemcnts includcsilicon dioxidc oxidizing clcmcnts such as indium, tin, and gallium in thc mctal alloy. *** porcclain in com- , (SlO, in lheporcclain and

Today was a very busy day for Ashley, the dental hygienist in our offlce. Ashley took alginate impressions on her first patient in the morning, who needed a nightguard. Since she was so busy, Ashley left the alginate impressions in the lab most of the morning. Ashley decided to place the impressions in a bowl of water so that they would not dry up before she had a chance to pour them up in dental stone. Which ofthe following was the result ofAshley Ieaving these impressions immersed in water for a few hours? Gelation Hysteresis Syneresis Imbibition

Imbibition Imbibition occurs when the impression absorbs water, which expands the dimensions of the impression. When this occurs, the impression is no longer accurate. Shrinkage will occur in alginate impressions, even when they are placed under 100% relative humidity. The shrinkage and exudation of water is called syneresis. Since shrinkage is undesirable (causes distortion ofimpressions), alginate impressions should not be left either inwater (v,ill expard) or exposed to air 6vill shink). They should be poured in.rmediately after they are taken to ensure accuracy. When immediate pouring is not possible, they may be stored briefly in a rnoist paper towel. Important: While taking an impression with alginate, it is advisable that the tray be placed in the mouth after all critical areas are wiped with alginate. Critical areas are buccal to the maxillary tuberosities and retromylohyoid space. Rest seats and guide planes should be covered with alginate as well as any other soft tissue undercuts. 1. Gefation is the term given to the setting process (c/rrrglng afrom sol to a gel) Iotes of hydrocolloid material. 2. Hysteresis refers to a material's characteristic ofhaving a melting tempera- ture different from its gelling temperature.

When inflannatory papillary hyperplasia is seen on the palate of a patient wearing a maxillary complete denture, the condidon is most likely going to be associated with: . A vitamin B deficiency A sudden increase in body weight A hypersensitivity ofthe patient to the acrylic denture base Ill-fitting dentures and a poor state of oral hygiene

Ill-fitting dentures and a poor state oforal hygiene The hyperplasia is produced in respons€ to ifiitation from movement ofthe denture and from accumu- lating food debris. The masses prescnt as painless,Iirm, pink, or red nodular pmliferations ofthl] mu- cosa. Candida albicans may contribute to the inflammation. Conditions that compromise the optimal function ofcomplete dentures: . Frenectomy; common for labial, less for buccal, rare for lingual. Surgery is usually Z-plasfy which must include fibrous attachment to bone. . . H;-permobile ridge: ifinflamed. trcat with a tissue conditioner. Lascr suryery may bc needcd Epulis Iissuratum: a hyperplastic tissue reaction caused by an ill-fitting or overextended flange in a denture. . Fibrous maxillary tuberosity: common occurrence when largc maxillary tuberosities contact mandibular retromolar pads. . Combination syndrome: refers to $hat is believed to be a specific pattem ofbone resorption in the anterior ponion ofan edenfulous maxilla, caused by wearing a complete denture opposing natural an- terior teeth. . Papillarl' h!perplasia: found in the palatal vault. Caused by local irritation, poor-fitting denture, poor oral hygiene, and leaving the denture dentures in all day and night. Candidiasis is the primary cause. . Paget's disease of bone: a denture or RPD in a periodically due to bone expansion , patient with this disorder may have to be remade 1. Alveoloplasty is the improvement ofthe alveolar bone by surgical reshaping or rcmoval. Noled,2.Palataltorishouldberemovedonlyif(l)itissolargcthatitfillsthevaultandprcvents ,...., :. r&a;- the formation of an adcquf,te denture base when it is undercut, (2) it interferes with the place- ment ofthe posterior palaral seal, or (3) ifthe patient is canccr phobic. 3. Vestibuloplasty: this tcchnique increases the relative height ofthe alveolar process by api. cally repositioning the alveolar mucosa and the buccinator mentalis, and mylohyoid mus- cles as they insert into the mandible. 4. Augmentation: (l) Bone gmfts (2) Hy&oxyapatite (3) Freeze-dried bone l'rources include anleior iliac crest ofthe hip or the rib)

The most frequent cause of porosities in a denture is Insufficient pressure on the flask during processing Insumcient material in the mold A rapid elevation in temperature to 212' F causing vaporization ofthe liquid Insufficient time for processing

Insufficient pressure on the flask during processing Acrylic resin used for denture repairs should be under 20-30 psi air pressure while being processed to help eliminate porosities. These porosities, ifpresent, will usually occur in the thickest part ofthe denture. Self-cured resins are generally used for repairs instead ofheat-cured resins because the risk of distorting the denture is less. l. When there is a rapid elevation in temperature causing vaporization ofthe liq- uid, the vapor is then trapped as gas bubbles. 2. Porosities will also occur if the packing and processing ofthe powder and liquid resin is too pllstic (stringl or sandy/. This permits the liquid to vaporize and, at the same time, does not allow sufficient pressure during closure of the flask.

Some impression materials are most accurate when at least 3mm of space is present between the impression tray and the oral tissue. Which impression material type shows this characteristic? Polyethers Polysulfides Silicones Irreversible hydrocolloids

Irreversible hydrocolloids - alginate Irreversible hydrocolloids (alginate) is most accurate when at least 3 mm ofspace exists befween the impression tray and the tissue. The other impression t)?es are most accurate when a small but definite space exists between the impression tray and the tissue. Remember: The setting time ofalginate is controlled by the amount of sodium phosphate that is present. Sodium phosphate serves a retard€r in this reaction, which means it slows down the process. As long as sodium phosphate is present, it will react with solu- ble calcium ions. Once all the sodium phosphate has reacted, then the sodium alginate re- acts with the remainins calcium ions and calcium alginate is formed. 1. Fast removal ofimpression from the mouth increases both the compresstve and tear strength of the impression. 2. All impressions must be rinsed and disinfected prior to pouring or sending to the laboratory. Soak or spray for a minimum of 10 minutes. Important: Always follow the manufacturer's recommendation for the specific product!! !

All of the following muscles are involved in elevating the mandible (closing the mouth) EXCEPT Masseter muscles Medial pterygoid muscles Lateral pterygoid muscles Temporalis muscles

Lateral pterygoid muscles (contract to cause protrusion) Muscles acting on the TMJ: . Opening (depress): lateral pterygoid, digastric (anterior belly) and the omohyoid muscles. . Closing (elevate): masseter, medial pterygoid, and the temporalis (anterior muscles. . . . Protrude: laterals pterygoid muscles acting together Retract: posterior fibers ofthe temporalis muscle Lateral displacem€nt: lateral pterygoid muscles acting individually. Important: . The lateral pterygoid muscles are mostly responsible for positioning and translating the condyles. . Ifthe mandible fractures, upward displacem€nt ofthe fractured segment would be caused by the closing muscles (masseter medial pterygoid, a d temporqlis).

An overextended distobuccal corner of a mandibular denture will push against which muscle during function? Zygomaticus Orbicularis oris Temporalis Masseter

Masseter This is a very common area ofoverextension and should be checked very well when de- livering the mandibular denture. The buccinator muscle lies under the denture flange in this area but the fibers run an- teroposterior in a horizontal plane and their action is weak; the anterior fibers of the masseter muscl€ pass outside the buccinator at the distobuccal comer ofthe mandibular denture and will push against the buccinator during function causing dislodgement. Important: When the posterior maxillary buccal space is entirely filled with the den- ture flange, the coronoid process may interfere with the denture upon opening of the rrouth. This will cause dislodgement olthe maxillary denture. L The superficial layer ofthe masseter muscle originates from the zygomatic process of the maxilla and inserts at the angle and lower lateral side of the ramus of the mandible. 2. The pterygomandibular raphe lies between the buccinator and superior constdctor muscles.

Which of the following is not associated with diabetes Delayed healing Rapidly progressing periodontal disease with marked alveolar bone loss Mucosal bleeding Increased calculus formation . A predilection for periapical abscesses

Mucosal bleeding (bleeding disorders arent associated with diabetes) Diabetes is a disease that can affect the whole body - betes face a higher than normal risk of oral health problems. The link between diabetes and the development of oral health problems is high blood sugar If the blood sugar is poorly controlled, it is more likely that oral health problems will arise. This is because uncontrolled diabetes impairs white blood cells, which are the body's main defense against bacterial infections that can occur in the mouth. Just as studies have shown that controlling blood sugar levels lowers the risk of major organ complications of diabetes - such as eye, heart, and nerve damage good diabetes control protect against the development oforal health problems. Even controlled diabetics present problems for the prosthodontist. The oral mucosa is prone to the development of sore spots which heal poorly and often become secondarily infected. Principles to keep in mind when constructing dentur€s for patients with any debilitating drsease: . . . . . . . Maximum extension Narrow occlusal table Non-pressure impression technique Do not use porcelain teeth Establish a good occlusion Reinforce oral hygiene Place on 6-month recall (sooner ifnecessary to reinfor ce oral hygiene)

Which semiadjustable articulator has the lower and upper members rigidly attached Arcon articulator Nonarcon articulator

Nonarcon articulator Thc capability of the articulator to closcly simulatc the movcments ofthc mandiblc is dcpcndcnt upon thc ajustabil- ity ofthc articulator elemcnts. f,lements of an articular; . Horizontal axis of rot|tion: variability ofthc position ofthc horizontal a\is ofrotation in rclationship to thc max- illary dental cast . Condylar incliration/fossa components: variability ofthc anglc ofthc cmincntia, dircctionaL guidance of thc supcrior, postcrior. and medial walls ofthc fossa, and ability to simulatc lalcrotmsive 'novemcnt . Inter Condyl|r distance: adjustability ofthe distancc bctwccn ihc vcrlical axcs ofrotation . . Bennett , ngle/Bennett movement:adjustability ofthc anglc and capability ofsimulating sidcshift movcmcnt Incisal guidance: adjustability and ability lo simulatc the aoterior guidancc ofthc natural dcntilion Types ofArticulators: . Cl^ss | sinple hi ge).-The movcmcnt ofthese articulators is limitcd to inaccuratc hinge opcning and closing arcs about a fixcd axis. The maximum intercuspation position is the only position that can be reproduced. Casts are arbitrarily mounted without use ofa facebow . Cl^ss ll (rlrbitrary nllrc -Plane line): Evolvcd from the Class I articulator dcsign, thesc aniculators arc capable oflatcral movement. Some are capablc ofvariablc location oflhc horizontal a{is ofrotalion //, et, arc si:e and capable o.f acceptitg a facebo\,), but a1l of this tlpe have fixed, arbitrary condylar inclination scllirrgs. verti- cal axcs ofrotation settings, and Bcnnctt Anglc. No adjustment ofthcsc posterior elcmcnts is availablc. Some havc a . provision for incisal guidance. Cl^.s lll (Seni-adiusta6le): These a(iculators can simulate lateral, protrusivc a d llcnnett movcnents to vary- ing degrces. By utilizing a facebow and intraoral maxillo-mandibular records, thesc articulators can bc pro- grammed to sinrulate thc curvi linear anatomical movcmcnts. Thcrc are cssentialiy two designs ofscmi-adjustablc articulators. Onc which has thc guidance ofcondylar movcmcnt in thc maxillary menbcr and the centers ofaxial roration in thc mandibular member This dcsign is termed arlon articulators. Thc ton-arcon arliculator dcsign has rhcsc elements reversed lo rhc occlusal planc -lhcuppcrand lower members arc rigidly attachcd. Theocclusal planc is relatively fixed of the nrandibular casl. Note: Arcon arc more accurate fbr fabricating fixed rcstorations, Nhile nonarcon providc casicr control in sctting tceth for complet€ 8nd partial dentures. 'Cl^ssly (filh adjustarle/: This class ofarticulatom accepls registration ofall anatomic dctcrminant ofocclusal morphology, and mosrcloscly simulates the movement dircctcd by thcsc controls. Thc postcrior clcmcnts ofthcsc controls are dircclcd and adjusted by an cxtm-oral tcchnjque called a p.ntogr{phic rcgistration. This class tvill ofthe natural dcntirion. This class is fully utilizcd in cxtcDsivc rcstorative accept a "hinge axis. kinemstic transfer bow. The incisal guidancc cl]n closely simulatc thc minations of lcmporomardibular joint dysfunction f?iMJr. paths procedures, as rvcll as adjunct to diagnostic dctcr_

After border molding the mandibuhr custom tray, it is important to check for dislodgement in order to detect areas of: Underextension of the tray Overextension of the tray Thickness of the tray None of the above

Overextension ofthe tray Check for dislodgement using the following techniques: . . . Pull gently upward on the patient's cheek Pull the lower lip gently forward in a horizontal direction Have the patient open widely . . Have the patient move the tongue into the right and leit buccal vestibules Have the patient protrude the tongue to touch the lower lip. Have the patient move the tip ofthe tongue from one corner olthe mouth to the other Dislodgement indicates overext€nsion and the border molding process should be refined in the offending area. Common areas ofoverextension ofthe mandibular impression are the labial and the truccal. This is suspected when the impression raises as the mouth is opened. The most critical area in the border-molding procedure for a maxillary denture is the mucogingival fold above the maxillary tuberosity area. This area is extremely important for maximal retention. Other critical areas are the labial frena in the midline and the frena in the bicuspid area. Overextension in these areas often leads to decreased reten- tion and tissue irritation. \ote: Pressure areas on the impression surface ofdentures is checked with PlP. Use dig- ital pressure only, one denture at a time. Special attention should be given to the hard palate and the mylohyoid ridge areas.

Most cases of which disease below are detected because patients complain that their dentures are not fitting since the bone has become too large for them? Addison's disease Paget's disease Hashimoto's disease Multiple sclerosis

Paget's disease Paget's disease (also called osteitis deformans) ofthebone is a chronic bone disorder in which bones becorne enlarged and deformed. The exact cause is not known. It is characterized by excessive breakdown of bone tissue, followed by abnormal bone formation. The new bone is shucturally enlarged, but weakened with healy calcifications. Important: Involvement of the skull may enlarge head size and cause hearing loss and blindness if the cranial nerves are damaged by the bone growth. Dental Considerations , Not"* l -relieving the tissue surface of the dentures and relining with resilient materials can extend the life of the dentures. However, remaking the dentures freouentlv is unavoidable. 1. Children who wear dentures and patient's with acromegaly who wear den- tures also often need to have their dentures relined or remade to allow for bone growth. 2. Diseases ofbone growth or expansion are much rarer than those ofbone loss. 3. Osteoporosis is the most common change associated with systemic disease. This condition is a generalized defect in which the quantity and quality ofbone in the skeleton is reduced.

Youre in the process of making complete maxillary denture for a patient. hich of the following will be a secondary support area Residual ridges Palatal rugae Incisive papilla Maxillary tuberosity Buccal vestibule

Palatal rugae The primary support areas of the maxillary complete denture are thc residual ridges (the ntatillan and palatine bones), lmportant: In the mandibular arch, the primary support area is the buccal shelf because of its bone structurc and its right anglc relationship to the occlusal plane. Proper extension into this area is necessary- to more widely distribute the load ofmastication. The residual ridges iflarge and broad can also be considered as lhe primary suppofl areas. Limiting structures oflhe maxillary denture: . ln the anterior region: the labial vestibule, which cxtcnds from the right buccal frenum to the leil laterally, from the right and lcft buccal vestibules extending in the posterior aspect on each side to the right and left hamular notches, respectively. . The posterior limit: extends to '$'ith junctions of moveable and immovable tissue. This coincides a line drawn through the hamular notches and approximately 2 mm posterior to the foveae palatiJle (vibrating I ine). Remember: . The secondary peripheral seal arca for a mandibular complete denture is thc anterior lin- gual border . Ifyou are labricating a mandibular complete denture for a patient with a knife-edge ridge, you need maximal extension of the denturc to help distribute the forces of occlusion over a Iarger arca Important: The most important factor for providing retention for complctc dentures is the pe- ripheral seal.

A plaster index is used to Maintain the vertical dimension of occlusion Maintain bite registration Preserve the face-bow transfer All of the above

Preserve the face-bow transfer When fabricating dentures, there are two methods used to preserve the face-bow transfer: l.Taking a plaster index ofthe occlusal surfaces of a maxillary denture before re- moving the denture from the articulator and cast (see picture below). 2. Placing a piece of 10x wax on the occlusal surfaces of the mandibular teeth and closing the articulator in centric relation. Chill the wa.x, drop the incisal guide pin to touch the incisal guide table (do not change). Important: The plaster index method is the preferred method due to possible distortion ofwax.

When preparing a tooth for either a full or partial veneer casting the functional cusp bevel is an integral part of the occlusion reduction phase. The functional cusp bevel Enhances resistarce form when buccal-tolingual forces are applied Serves as a positive stop when the casting is seated during cementation Relieves the functional cusp from additional stresses when the restoration is loaded in the long axis ofthe tooth Provides space for restorative material of adequate thickness in an area of heavy occlusal contact

Provides space for restorative material of adequate thickness in an area of heavy occlusal contact The functional cusp bevel is an area ofreduction over the functional cusps that allows for cxtm thickness ofmetal in this area ofhealy occlusal contact in centric occlusion as well as in lateral movcments. The functional cusps are those that oppose thc ccntral fossae ofthe t€eth in the op- postte arch (buccal cusps on mandibular teeth, lingual cusps on ma-tilldry teetu. Thc primary reason for choosing a r/4 crown over a full cast crown is tooth structure is spared. Other advantages to the use of partial veneer restorations (three-quarter & seven-eighths crowns). . A great deal ofthc margin is in an area accessible to the dentist for finishing and to the pa- tient for cleaning. . Less ofthe restoration margin is in close proximity to the gingival crevice, thus lessening the opportunities for periodontal irritation. . . Can be more easily seated completely during cementation. with at least part ofthe margin visible, complete seating ofa partial veneer crown is more easily verificd by direct vision. . Ifit is evernecessary to conduct an electric pulp test on the tooth, a portion ofenamel is unvcneered and accessible. .. , 1. The path ofinsertion ofan anterior three-quarter cro*'n parallels the incisal l/2 ,\orec to 2/3 of the labial surface, not the long axis of the tooth. For a posterior three- ,"-;* quarter crown it parallels the long axis ofthe tooth. 2. A pin modified three-quarter crown can preserve the facial surface and one prox- imal surface. This is preferred in cases which require repairing of severe lingual abrasion on incisors and canines, avoiding other more destructive options like full veneer metal-ceramic restorations.

Which of the following impression material has the longest working time Polyether Polysulfide Reversible hydocolloid Polyvinyl siloxane

Reversible hydocolloid \ote: Reversible and irreversible hydrocolloids have the advantage of wetting oral surfaces \\ ell. but they have very limited dimensional stability because they include as much as 85% $ater in their composition.

All of the following are considered to be base metals EXCEPT Nickel Cobalt Chromium Silver

Silver Silver is a precious metal. Metals are classified as noble elements based on their lack of chemical reactivity. The noble metals include gold, platinum, palladium, and other inert metals. Alloys with less than 25olo noble elements are called base metals. Note: Silver is not considered noble; it is reactive and improves castability but can cause porcelain "greening." Remember: Noble metals are precious, but not all precious metals re noble (i.e., sil- ver). Base metal (nickel, chromium and cobalt) alloy advartages are principally found only in their strength and low density. As compared to T)?e IV gold alloys, base metal alloys have: . A higher resistance to deflection in thin segments . A lower yield strength . A higher modulus ofelasticity . A lower specific gravity . A much higher melting temperature (230CF to 260CF) Remember: The nickel in the composition ofbase metal alloys is responsible for ductil- iq of the alloy. It is also measured as a percentage of elongation and determines how much margins can be closed by bumishing. Chromium produces a passivating film for conosion resistance and cobalt increases the rigidity ofthe alloy.

What is the general rule for sprue pin diameter when using centrifugal type of casting machine The diameter of the sprue pin should be equal to or greater than the thickest portion of the pattem The diameter of the sprue pin should be equal to or smaller thar the thickest portion of the pattem The diameter of the sprue pin should be equal to or greater than the thinnest portion ofthe pattem The diameter of the sprue pin should be equal to or smaller than the thinnest portion ofthe pattem

The diameter of the sprue pin should be equal to or greater than the thickest portion of the pattem The sprue is a small diameter (10-12 gauge) pin made ofwax or plastic. A 10 gauge sprue pin can be used on most patterns, while the l2 gauge is used on small premolar pattems. The sprue should be attached to the wax pattem at its point ofgreatest bulk and at an angle (45) that will allow the incoming gold to flow freely to all portions of the mold. Spruing at a thin area of the pattem can produce the same result as using a back porosity. This is caused by turbulence in the flow ofthe molten metal which in tum creates a shrinkage void, or suck-back porosity. sprue that is too small -shrink Note: Low investment permeability and insullicient wind-up of the casting machine may also cause this shrink back porosity.

The most important clincial property of cement is solubility Increasing a cements powder to liquid ratio increases the solubility of the cement The first statement is true; the second statement is false The first statement is false; the second statement is true Both statements are true Both stalements are false

The first statement is true; the second statement is false li.rcasins a cement's Lutins agents /.prrdrrt: . Zinc phosphaae po$dcr,lo,liquid ratio decrcases thc solubility ofrhe ccmcnr. cement: onc ofthc oldesr and most widcly uscd ccmcnts, zinc phosphatc Jrd rlirinst $hich nc$ ccmcnts arc mcasulcd. Advantages: Iong rccord ofclinical acceprability, high compres- .:': strcngth. acccptably thin film thickncss. Disadvantages: low initial pH which may lcad to poslccmentation .:rr:trr rtr'. lack ofan abilily to bond chcmically to tooth structure and lack ofan anlicariogenic cflcct.lmportant: Z:n. phosfhatc ccmcnt is mixcd using thc "frozen slab" rcchniquc which grcarly ccmcnt is thc stan- cxtcnds thc working timc fb.t, J ' .ak h as 340'i;). Note: Tlc pH of ncwly mixcd zinc phospharc ccmcnt is |ndcf 2 ( tbo lalers ol vtnish m sl ;.)ep!ieloraftlertoprotectthepulp)blJtnscslo5.9within24boursandisncarlyneutralat.l8hours.Thcfilm ra:.kn.ss ofzinc pbosphatc is about 25 . !rm- Zinc pohcarbor]late cement: also known as zinc polyacrylarc ccmcnq was one of the first chemically adhe- site denial mate.ials. Thc adhcsivc bond is primarily to cnamcl although a wcakcrbond io dcntin aiso forms. This :. Ju. ro rhe faci that bonding appcars lo be the rcsult ofa chelation rcaction bcrwccn the carboxyl groups .J:x.nt and calcium in thc tooth structure; hencc, tlrc more highly mincmlizcd Ihc tooth structure, rhe sronger the :{nd.\drsntsges:kindlothepulp,chcmicallybondslotoorhstrxchrre.Disadvantagestshortworkingtimc,rc, ;urrss scparalc tooth conditioning stcp prior to ccmcnlation. Note: il is more viscous whcn mixed and has a shorle. \rrking timc than docs zinc . phosphate cement. Class ionomercement: Advantages: chemical bond ro cnamcl and dentin, anticariogenic cflcctlrcleases ,rr,1r. cocllicicnt oftbcrmal cxpansion similar to that oftooth structurc, high comprcssivc strcngth, low solubil- :n Disadvantages: low initial pH which may lead to postccmentation scnsiriviry. scnsirivity ro both moisturc .onramination and dcsiccation. Notet Its mcchanical propcrties . Resin-modified glass ionomerluting agents; have propcnics arc supcrior to zinc phosphatc similarto glass ionomcrccmcnts. but have higher 5trenglh and lower solubility. Note: Thcy should not bc uscd wilh all-ccramic rcstorations dues to rcports ofcc- r3nlic fracturc, most likcly thc rcsult ofcxpansion from watc. absorprion. . Resin luting agentsr arc unfillcd resins that bond to dentin, which is achicved with organophosphonatcs, /2-1,)- dro]reth\ I ttrcthacrylate or 4-mcthacryloyloxycthyl trimellirarc anhydridc (4-Mf,TA). Advanrrges: hr!h comprcssivc strcnSth, low solubility. Disadvant.ges: irritating cfl'ects on thc pulp, high film thichcss p IHEMAII, 1]r'l. Note: As a gcncml nrlc, rcsin cements are thc bcst choice for luting ccramic rcstorarions_ Important: Thc film thickncss at thc margins shouid be minimizcd to rcduce the solubility of the luting agenr. Tl.ough c|rcful tcchnique, a marginal adaptation below l0 pm can bc obrained consistcntly. Noter Factors that in, .r.asc the cement spacc for crowns include (l) thc usc ofdic spacers (2.)incrcased of rhc and polycarboxy- expansion ofthc investmcnt mold. Iu, -?J

The most important benefit of an overdenture (root retained denture) is The psychological comfort ofavoiding the loss of all teeth The continuous functional feedback for the neuromuscular system from proprioceptors in the periodontal membrane The preservation of the alveolar ridge The improved support and stability for the denture The increased retention ofthe denture

The preservation of the alveolar ridge The overdenture is a denture whose base is constructed to cover all ofthe existing resid- ual ridge and selected roots. Retained roots help to prevent resorption of the alveolar ridges. These roots also improve retention and afford the patient some proprioceptive sense of "natufalness" in function ofthe dentures. It is not always necessary to cover a root beneath an overdenture, however, ifa root is not covered, the exposed surfaces are highly susceptible to decay, The oral hygiene of the patient must be impeccable to prevent the decay ofthese roots. Note: Retained roots are the most common findings when taking routine panoramic radiographs of patients who wear complete dentures (rol necessarily overdentures). Important: The general rule for retained root tips with no radiolucency and the corti- cal margin ofbone intact is that they can remain in place; however, the patient should be informed oftheir presence. They should be removed if the cortical plate is perforated and/or the PDL or radiolucent area is getting larger

Youre taking an impression with alginate and unknown to you there is debris on the tissue. How will this effect the final impression? lt will be grainy It will tear easily There will be irregularly shaped voids It will be distorted

There will be irregularly shaped voids Chart on page 76 has more info

In mixing dental stone, why should the powder be sprinkled onto the water in the bowl? The addition of powder prevents the mix from becoming exothermic This is not recommended; the water should be added to the powder . This process results in better powder mixing and reduced chance for air bubbles The powder is added to the water to avoid using more than one bowl

This process results in better powder mixing and reduced chance for air bubbles Dental gypsum products are made up of hemihydrate particles whose size' shape, and porosity differ for each material. These gypsum-based powders require different amounts ofwater for mixing because the different particle shapes produce different packing efficiencies that affect the amount ofexcess water required for making a suitable mix- ture. llixing: . lVater/powder ratio: the water/powder ratio is an important factor in detennining physical properties. When a high proportion ofwater is used, the powder particles are farther apart. This results in less expansion with a retarded setting time and a weaker product. Dental plasters generally require about twice as much water compared to stones. Plaster has a higher setting expansion thar does stone. . . \\'ater temperature: generally, the cold€r the water, the longer the setting time Spatulation: rapid spatulation for a time equal to normal hand mixing for 1 minute accelerates setting time and produces greatest strength. Do not spatulate to the point $ here the mixture starts to harden. This will produce a cast that is much weaker. . Accelerators and retarders - Retarder: borax. sodium citrate (modifiers): - Accelerators: gypsum, potassium sulfate, NaCl 28% Remember: The setting expansion ofany gypsum product is a function ofcalcium sulfate dihydrate cystal growth. Some is the result of thermal expansion.

The absolute maximum number of posterior teeth which can be safely replaced with a fixed bridge One Two Three Four

Three- and Three teeth should be replaced only under ideal conditions (any bridge replacing more than two teeth should be considered high risk mportant: One factor that limits th€ length ofthe pontic span is the abutm€nt teeth's ability to accept the ad- ditional occlusal load while providing adequatc support to the cemented fixed partial denturc. Ant€'s law stales that the root surface arca ofthe abutment tcelh supported by bone must equal or surpass the root surface area ofthe teeth being replaced with pontics. An edentulous spacc involving four adjacent te€th otherthan four incisors is usually best treated lvith a re- movable partial denlure. [f more than one edentulous space exists in the same arch, even though each of thcm could be individually rcstorcd with a bridge, it may be dcsirable to restore them with a removabie par- tial denture. This is especially true ifthe spaccs arc bilateral and each one involves two or more missing teeth Third molars can rarely be used as abutments, sinc€ they fiequently display incomplete eruption; shon, fused roots; and a marked mesial inclination in the absence ofa second molar Note: Diverging multirooled, curv€d, and broad labiolinglal roots are prefened over fused, single, conical, and round circumferential roots. Remember: . Splinling adjacent abumlent teeth in a fixed bridge is primarily done to improve the distrit ution ofthe occlusal load, . prcvent recession, lhe correct contour of the cro$n's gingival one-third to one-fifth and interproximal areas are most impofiant in the final In order to maintain and protect the health ofthe gingival tissues and restoratioD, .An anterior fixed bridge is contraindicated when there is considerable resorption ofthe r€sidual bridge. A removable panial denrure would be indicated in this case. . . Horizontal loads 1ol &,c"t on natural or abutmcnt teeth are most deslructive to the Abuimenls with hatfor l€ss ofbone support and loss ofattachment have a poor prognosis. . \\'hen replacing the maxillary or mandibular canine, the central and lateral should be splinled to prcvent lateral drifting oflhe fixed bridge. . Aburment teeth must align to a common path of insertion (/o/ orvious reasons when lryng lo seat lhe hrklge). . . . Short root-to-crown r^lio (less lhan./:21 with conical roots should be avoided as abutmenls. \atural reeth exert more force than an RPD or complete denture when opposing a fixed bridge Ideaff)--, rhe supportive surface area (peiodontium) of lhe abutment teeth should be equal to but not leis than !ha! ofthe teeth to be replaced

The primary reasons for obtaining the most extensive area coverge for a mandibular complete denture are To increase the capacity of underlying struchrres to withstand the stress due to biting force and to improve appearance To provide balanced occlusion and to increase tongue space To increase the capacity of the underlying structures to withstand the stress due to biting force and to increase the effectivenessofthe seal To improve retention and to increase tongue space

To increase the capacity of the underlying structures to withstand the stress due to biting force and to increase the effectivenessofthe seal Key point - undcrcxtcnsion ofthc pcriphcral bordcr ofa complctc mandibular dcntrrrc dccrcascs tissuc-bear- ing surfaccs, lhcrcby affccting dcnturc stability. Merked ridge resorption will occur ifa mandibular complctc dcnturc base terminates short ofthc rctromolar pad- Thc underlying basal bote (be eath lhe retromoldrpdd) is rcsistant lo rcsorption. Covemge ofthis arca will also provide some bordcr seal- An overload ofthe mucosa will occur iflhc bascs covcring thc area are too smali in oul- do marillary den|r,"es, but rather on dcnturc stabiljty in covcring as much basal bonc as Remember: Mandibular denn[cs do not rely on suction from a pcriphcral scal for retention /ds possiblc $ithout i'rpinging on thc musclc attachmcnts. Thc active bord€rmolding perfonned bythc lips, chccks, and tonguc determines the ofa mandibular arch, thus establishirg ma{imal basc bonc covcrage. Limiting structurcs ofthc mrndibular dcnturc: . Mandibular lnterior labial area: thc action of the mentalis musclc and the mucolabial fold dctcrmincs thc cx- tcnsion ofthe denture flangc jn lhis arca. . Mandibular labial frenum: lhis band offib.ous conncctive tissue hclDs attach thc orbicularis oris musclc. Thc sizc ofthis s(ructurc limits thc cxtcnsion ofthc dcnturc bordcr. thc thickncss oflhc dcnturc basc, and aflects thc position olthc mandibular tccth. . Buccal vestibule: is infiucnccd by the buccinator musclc which has musclc fibcrs that run in an obliquc dircc- provides the best support for thc mandibular dcnturc. Tlis arca is rcfcrred to as thc buccrl shelf. tion and thcrcforc bave littlc displacing aclion- Propcr cxtcnsion into this arca . :|Iasscter area: thc dcnturc is limited in a latcral dircction by lbc action ofthc massctcr musclc. . Retromolar padi marks thc distal termination ofcdcntulous ridgc. This structurc nccds to bc covcrcd fbr sup- pon and rctcntion. By doing lhis thc intcgrity ofbonc in lhis arca is maintaincd and allows for support. ' Lingurl frenum: thc proper bordcrs must bc cstablished with movemcnts ofthc longuc whcn bordcr molding. Thc . ' gcnioglossus musclc inlluenccs lhe length ofthc flangc during normal movcmcnts ofthe tongue. Sublingual gland sreai maximum cxtcnsion dcsircd without ovcrcxtcnsion. \ll lohtoid area: thc flangc in this arca must accommodatc the movcmcnt ofthc mylohyoid musclc in swallow- ing . Retromllohloid area: this area is limitcd posteriorlyby thc action ofthc palatoglossus musclc and inferiorly by rhr lingual slip ofthc superior constrictor musclc. Ifthcsc musclcs arc impingcd upon, thc paticnt may dcvclop a sora throat. Notei This is often ahc most diflicult are to manaqc.

Rotational movements take place in which compartment of the TMJ? - Upper (mandibular fossa - articular disc) compartment - Lower (condyle - articular disc) compartment - Both the upper and lower compartments

- Lower (condyle - articular disc) compartment The temporomandibularjoints are considered to be the most complex joints body because they must provide for rotational movements, sliding movements (trqnskr- to\) motion) and an infrnite range ofcombined movements and functions, unlike any other joint in the body. When the mouth opens, two distinct motions occur at thejoint. The first motion is rota- tion around a horizontal axis through the condylar heads. The second motion is translation. The condyle and meniscus move together anteriorly beneath the articular eminence. ln the lower (condyle - articular disc) compartment, only a hinge-type or rotary mo- tion can occur. This rotational or terminal hinge-axis opening oflhe mandible is possible only when the mandible is retruded in centric relation with a conscious effort by the patient or by the dentist's control. Note: A pure hinging movement is possible only in the terminal hinge position. ln the upper (mandibular./bssa in the human - articulqr disc) compa'rtment, only sliding movements or translatory motion can occur. When the lateral pterygoid muscles contract simulta- neously, the discs and condyles slide forward down over the articular eminence sion), or can move backwards together (retrusion) during opening and closing of the mouth, respectively. Remember: The TMJ is a ginglymoarthrodial joint (prctru- fn eaning that it glides and rotates), permitting both hinge-like rotation and sliding (gliding) movements. Ginglymus means rotation, and arthrodial means freely movable.

The ideal crown to root ratio of a tooth to be utilized as a bridge abutment is 3:1 2:1 1:2 1:1

1:2 This high a ratio is rarely achieved, however, and a ratio of 2:3 is a more realistic optimum. A ratio of l:1 is the minimum ratio that is acceptable for a prospective abutment under normal circumstances. The crown-to-root ratio alone is not adequate criteria for evaluating a prospective abu! ment tooth. Root configuration is an important point in the assessment ofan abutment's suitability from a periodontal standpoint. Roots that are broader labiolingually than they are mesiodistally are preferable to roots which are round in cross section. Multi-rooted posterior teeth with widely separated roots will offer better periodontal support than roots which converge, fuse, or generally present a conical conhguration. Single-rooted teeth with an irregular configuration or with some curvature in the apical third ofthe root are preferable to the tooth which has a nearly perfect taper. Root surface area of the prospective abutments should also be evaluated. All ofthe following are factors in fixed bridgework design: . . Root configuration Crown-to-root ratio . . Axial alignment of teeth Length ofthe lever arm (span) Note: R€placing three teeth is maximum!l! Remember: Parallelism ofabutment preparations is best determined by the long axis of the DreDarations.

The torus palatinus is a hard bony enlrgement that occurs in the midline of the roof of the mouth and is found in 2% of the population 20% of the population 50% of the population 75% of the population

20% of the population Palatal tori are bony enlargements located at the midline ofthe hard palate. They occur in approximately 20% ofthe population and are more prevalent in women than men. They usually reach maximum size in the third or fouth decade. Because the torus is usually cov- ered by thinner and less resilient mucosa than the residual ridge, it may act as a fulcrum and cause rocking ofthe ma"rillary denture. Because the soft tissues over the torus are generally thin and have a poor blood supply, post-operative healing is slow. It is best to cover the opemted site with a surgical stent lined with a sedative dressing. Ifa patient is having all oftheir maxillary teeth out at one time, it is best to also remove the tod at the same time. Note: Palatal tori are usually not removed for denture fabrication whereas mandibular tori are usually removed prior to denture fabrication. The following conditions warrart re- moval ofpalatal tori, ifit: (1) impinges on the soft palate (2) is so large that it fills the vault and prevents the formation ofan adequate dentue base (3) is undercut (4) extends so far posteriorly interfering with the posterior palatal seal (5) is psychologically disturbing to the patient (cancetphobia) .

All new dentures should be evaluted 3 hours after delivery 12 hours after delivery 24 hours afier delivery 48 hours after delivery

24 hours afier delivery This is done for the purpose of correcting undetected enors. Tissue trauna attributed to denture function manifests as h)?eremia, inflammation, ulceration, and pain. The basic sequence ofthe clinical procedure for a 24 hour recall appointment is: l. Remove the dentures from the mouth. 2. Thoroughly examine the mouth. 3. Ask the patient about the areas oftissue trauma which have been obseryed. 4. Pemit the patient to describe additional complaints. *** After collecting all ofthe diagnostic information, the dentist can determine the source ofthe problem and the cure. Remember: During the first few days following the insertion of complete dentures, the patient should expect some difficulty in masticating most foods and excessive saliva *hich is due to reflex parasympathetic stimulation ofthe salivnry glands. Over time this u ill subside and become normal. Important: Occlusal disharmony can be most accurately corrected on the articulator after patient remounting procedures.

Immediate dentures should be rescheduled for relines I month and 3 months post extraction 4 months and 7 months post extraction 5 months and l0 months post extraction 1 year and 2 years postexhaction

5 months and l0 months post extraction Recontouring of the healing ridge progresses rapidly for four to six months and does not become stable in fonn until l0 -12 months post extraction. Due to this, immediate dentures become progressively more ill-fitting. They should be relined five months and ten months after delivery in order to compensate for contour changes. Note: This is a gen- eral timeline; each case needs to be evaluated monthly and, if necessary, relines performed. A reline is indicated on any denture when the diagnostic information indicates that a re- line rvill effectively solve the patient's chief complaint - peripheral areas when the denture base adaptation is the major defect in the prosthesis. A reline is contraindicated when there is excessive overclosure of the vertical dimension - a large decrease in veftical dimension. In this case, new dentures are indicated at the proper vertical dimension. Note: When a patient wears a complete maxillary denture against the six urandibular an- terior teeth, it is very common to have to do a reline every so often due to the loss of bone structure in the anterior maxillary arch ridge. -evidenced by a flabby maxillary anterior

All ceramic restorations are popular because of their superior esthetics and generally favorable gingival tissue response. The finish line of choice when fabricating an all ceramic crown is 90 degree, 1.0 mm shoulder Bevel Chamfer 45 degree, .25 mm shoulder with a bevel

90 degree, 1.0 mm shoulder Unlike thc metal-ceramic .estoration, which will accept any marginal design (a bevel, chamfer, or shoulder), marginal tooth prepamtion for the all-ceramic crown or porcelainjacket crown must be a shoulder foptrn ally 90 degrees and 1.0 mm). There are indications and contraindications for all-ceramic crowns, and violating these will compromise the success of a restoration. All-ceramic crowns generally are accepted to be superior esthetically, but their lack ofa metal substructure makes them inherently weak, As a result, they are rarely indicated for use on posterior teeth, and are not indicated at all for anterior teeth in a Class III edge-to-edge relationship, where the occlusal forces can subject them to fracture. There are few acceptable instances where all-ceramic crowns may fuuction as irxed partial denture abutments, such as during the replacement ofanterior teeth when a favorable anterior guidance occlusal scheme exists. The main reason for the use of porcelain jacket crowns and all-ceramic crowns is superior es- thetics. These tlpes of crowns have the capability to mimic the optical properties ofthe natural tooth. However, the guidelines for usage, such as tooth preparation, are more critical and in gen- eral more complicated than for the metal-ceramic restorations. ln general, it is advisable to use these more esthetic crowns only in the anterior segment, where esthetics is the dominant factor. Dilferent materials used in the fabrication ofa full crown require dilferent marginal designs: . All-ceramic or porcelain . jacket crowns -shoulder \Ietal ceramic with porcelain extended to maryinal edge . Vetal ceramic with metal collars shoulder with beYel or chamfer . *** Full gold crown - bevel (feather edge) or chamfer

A non rigid connector is comprised of A key A keyway A key and a keyway

A key and a keyway A nonrigid connector is a broken-stress mechanical union ofretainer and pontic, instead ofthe usual rigid, solderjoint. The most commonly used nonrigid design consists ofa T-shaped key that is attached to the pontic and a dovetail keyway placed within the retainer. The path ofinsertion ofthe key into the keyway should be parallel to the pathway of the retainer not involved with the keyway. Its use is restricted to a short span bridge, replacing one tooth. It is indicated when retainers cannot be prepar€d to draw together without excessive tooth reduction. Pros- theses rvith nonrigid connectors should not be used ifprospective abutment teeth exhibit significant mobility. Important: When abutment teeth are in normal alignment and have good bone support tcanine and /irst molar.r), the connectors of choice are solder joints.

Which one of the following best describes the term "quenching" A metal is elevated to a temperature above room temperature and held there for a length of time A metal is rapidly cooled frorn an elevated temperature to room temperature or below Softening a metal by controlled heating and cooling None of the above

A metal is rapidly cooled frorn an elevated temperature to room temperature or below It is usually performed when a complete gold crown is cast and immediately quenched in u ater. This softens the alloy, making it more malleable for frnishing procedures. Important: To achieve a softened condition for a Type III dental gold alloy, the casting should be quenched in water immediately or within 30-40 seconds ofbeing made. . l Hert treatment is the subjection of metals and alloys to controlled heating }-oa3'. and cooling afier fabrication to relieve intemal stresses and improve their phys- '.9." ical properties. Methods include annealing, quenching, and tempering. 2. Annealing is controlled cooling of a material to increase ductility and strength. The process involves first h eaing a mateial (usually glass or metal) for a given time at a given temperature, followed by slow cooling. 3. Fritting is a process ofmanufacturing low and medium fusing porcelains. It involves raw constituents ofporcelain to be fused, quenched, and ground back to an extremely fine powder This "frit" can be added over by other metallic substances to produce color in porcelain.

Which of the following are indications for fixed bridgework or important considerations to think about when contemplating the fabrication of fixed bridgework for a patient? . A limited number of edentulous areas which would not otherwise be more satisfactorily restored with a removable partial denture . The need to prevent the over-eruption ofopposing teeth and the drift of teeth neighboring the edentulous space . The presence of suitable abutment teeth favorable crown/root ratio, adequate alveolar support, absence ofapical pathology, etc. . . Esthetics Patient motivation, including time availability . . Clinical and technical ability All ofthe above

All ofthe above Contraindications for fi xed bridgework: . . . . . . Poor oral hygiene High caries rate Multiple spaces in the arch or teeth likely to be lost in the near future Space not detrimental to the maintenance of arch stability or dental health Unacceptable occlusion Bruxism l. If the clinical and technical skills ofthe dentist do not match the demands \ote+ ofthe case, fixed bridgework should not be undertaken because a failed bridge '.;** . is likely to be more detrimental to dental health than a failed removable partial d€nture. 2.Unless specifrcally contraindicated, fixed restorations are always the treat- ment of choice. 3. Fixed bridgework can be used in conjunction with removable partials. Ex- ample: A patient with a couple ofmissing anterior teeth and no posterior teeth. Treatment could be fixed bridgework in the anterior and a partial denture re- placing posterior teeth. 4. Although somewhat controversial, the literature recommends that you should not splint natural teeth and implants in a fixed partial denture. Implants have no periodontal ligament and so do not have the same capacity to ab- sorb shocks as do natural teeth (they have dffirent mobilityb). When this bridge is subject to occlusal loading, the difference has been shown to be detrimental to the natural teeth as well as cause bone loss around the im- Dlants.

An edentulous patient has slight undercuts on both tuberosities and also on the facial of the anterior maxilla. To construct a satisfactory maxillary complete denture, you should reduce which of the following? All undercuts The anterior undercut only Both tuberosity undercuts None ofthem

All undercuts Undercut tuberosities will interfere with the seating ofthe denture. Explanation of answer: Maxillary anterior undercuts are very cornmon and present no special problems unless accompanied by large bilateral posterior undercuts. Even this situation can usually be managed by reducing the inner surlace ofthe denture lateral to the tuberosities. The maxillary sinus appears to enlarge throughout life if it is not restricted by natural teeth or dentures. As the sinus enlarges, the tuberosity moves downward. Ifthere is no con- tact with the retromolar pad at the vertical dimension ofocclusion, the tuberosity must be reduced. If a fow tuberosity is not removed before constructing new dentures (C/C), an acciden- tally underextended mandibular denture will probably be made and limited space to po- sition posterior teeth will occur. A submucosal vestibuloplasty is usually performed on the maxillary arch to improve the available denture base area. This procedure is favored because no raw tissue surface remains to granulate and re-epithelialize.

Soldering flux is composed of all the following EXCEPT Sodium pyroborate Alum Borax Silica

Alum Soldering flux dissolves surface oxides and allows the melted solder to wet and flow onto the adjoining allow surfaces. It is composed of sodium pyroborate (5 rca ( 10%) . 5%.), borax (35%.), and sil- In addition to the usual reducing and cleaning agents incorporated in a flur, a flux used for soldering stainless steel or cobalFchromium alloys also contains a fluoride to dissolve the passivating film supplied by the chromivm (chromium osidey'lz). The solder will not wet the metal $ hen such a film is present. Potassium fluoride is the most common agent. Soldering is thejoining ofmetal components by a filler metal, or solder, which is fused to each ofthe pans beingjoined. To be biologically and mechanically acceptable, a solderjoint should be circular in form and occupy the region ofthe contact area. The strength ofthe solderjoint is increased by increasing the height ofit (as opposed to the wldlr. Not€: The recommended distance /i|ldrlr/ between the parts to be joined should be 0.25 mm. Cleanliness is the prime prerequisite ofsoldering. Corrosion products, such as oxides and sultides that are present as a result ofthe casting process, interfere with bonding. Flux is placed on the surfaces to be soldered before they are heated. When it melts, the flux displaces gases and removes conosion products by either combining with them or reducing them. The flux in tum is displaced by the solder, which can now form an interface with and bond to the surface being soldered. Note: Antiflux is a material used to outline the area to be soldered in order to restrict the flow of solder. The most common antiflux is a soft graphite pencil. Iron oxide (rouge) may also be used.

Assume that a patient wearing complete dentures for a number of years is given an oral examination and it is determined that the vertical dimension of occlusion has been decreased. This would cause: An increased vertical dimension that leaves the teeth in a clenched, closed relation in normal positions An occluding vertical dimension that results in an excessive interocclusal distance when the mandible is in the rest position . An insufficient amount of interarch distance because of heavy, bony ridges . An inability to open the mandible because of temporomandibular joint pathosis

An occluding vertical dimension that results in an excessive interocclusal distance when the mandible is in the rest position Interocclusal distance: also called "freeway space" is the vertical distance or space between the incisal and occlusal surfaces ofthe maxillary and mandibular teeth with the mandible in the physiological rest position. The average interocclusal distalce is about 3 mm. Too much interocclusal distance may re- sult in muscuiar imbalance. vertical dimension of occlusion is the vertical length ofthc face as measured between two arbitrarily (occluJiorl ,'rrril are in contact in centric relation. Excessive vertical dimension may result in trauma to thc selected points, one above and one below the mouth, when the teeth or any substitute ma1e'rial underlling supporting tissues (in a derlrtre patient) and strrir'jng ofthe closing muscles as well as ad\erseft affecting the interocclusal distance (decreasedfreewal, space). \ertical dimension of rest is the vertical length of the face as measured between two arbitrarily se- lecred points. one above and one below the mouth, when the mandible is in the rest position; in the phlsiologicalJy healthy individual, there will always be a vertical space between the teeth (freewal' space) \hen the mandible is in the rest position. This position is important in complete dentute fabrication be- cause it p.ovides a guide to the vertical dimension ofthe occlusion. l. Vertical Dimension ofOcclusion + Interccclusal Distance = VerticalDimellsion ofRest. Notesi 2. Thc vcrtical dimension ofrest is always greater than the vertical dimcnsion ofocclusion. ** l. A protrusive record registe$ the anterior-inferior condyle path at one particular point in rhe translatory movement ofthe condyles. Some clinicians use this q?e ofrecord to de- temine the amount of space between maxillary and mandibular teeth or occlusal rims in order to maintain balanced occlusion throughout the mandibular functional range of movement $'hen aniculating teeth. 4. Thc space that opens between the posteriorteeth during anterior movemcnt ofthe mandible is called Christensen's PheDomenon. This posterior separation is increased if the incisal guidance is increased. Tte amount of posterior separation is affccted by both the incisal guidance and the horizontal condylar guidance. The separation is increased as both IG and HCG increase teriorly. -the effect ofIC is greater anteriorly and the effect ofHCG is greater pos-

The inferior surface of the maxillary occlusion rim should be parallel to Frankfort's plane Camper's line Fox plane Horizontal condylar inclination

Camper's line (an imaginary line from the inferior border of the ala of the nose to the tragus of the ear) Occlusion rims are the resultant product after adding base plate wax to a record base in order to approximate the tooth position and arch form expected in the completed denture, Occlusion rims are used to: . . . Determine and establish the vertical dimension ofocclusion Make maxillo-mandibular jaw records Establish and locate the future oosition ofthe artificial teeth l. A good slarting point for determining the vertical length ofthe maxillary occlusion rim is a point approximately 2 mm below the upper lip when it is re- lared. 2. When recording centric relation for a removable partial denture, the occlusion rirn should be attached to the completed partial denture framework in- stead ofa record base as used with a complete dentue. 3. Ifat the tooth try-in appointment the teeth need to be adjusted to correct the centric occlusion, the best way to do this is to take a new centric relation record and remount.

The path of insertion for an anterior 3/4 crown should Be perpendicular to the incisal one-half of the labial surface rather than the long axis of the tooth Be parallel to the incisal one-half to two-thirds ofthe labial surface rather than the long axis ofthe tooth Be parallel to the long axis ofthe tooth Be parallel to the cervical one-third ofthe labial surface rather than the long axis of the tooth

Be parallel to the incisal one-half to two-thirds ofthe labial surface rather than the long axis ofthe tooth Important: If the path of insertion is made parallel to the long axis ofthe tooth, the labio-incisal comer will be sacrificed and an unnecessary display of gold will result. Two factors that must be dealt with successfully to produce an anterior % crown with a min- imat display ofgold: l. Path of insertion and groove placem€nt 2. Placement and instrumentation of extensions . Proximal extensions must be done with thin diamonds and hand instruments from a lingual approach to minimize the display ofgold. They should be extended facially to a cleansable area without destroying the facial contour ofthe tootlt. Note: The anterior three-quarter crown is not used as fiequently today as it once was. Unsightly and unnecessary displays of gold in poor examples of this restoration have made it less popular with the public and dentists alike. However, the standard three-quarter crown on a maxillary anterior tooth need not show large quantities ofgold ifprepared correctly.

Dental stone and dental plaster both have a slightly different type of principal component (calcium sulfate hemihydrate). Dental plaster has Beta-hemihydrate and dental stone has gamma-hemihydrate Alpha-hemihydrate and dental stone has beta-hemihydrate Gamma-hemihydrate and dental stone has beta-hemihydrate Beta-hemihydrate and dental stone has alpha-hemihydrate

Beta-hemihydrate and dental stone has alpha-hemihydrate The principal constituent of the dental plasters and stones is the calcium sulfate hemihydrate. Depending upon the method of calcination, different forms of the hemihydrate can be obtained -either alpha or beta hemihy&ate. The beta-hemihydrate is more popularly known as plaster ofParis, and these crystals are characterized by their sponginess and irregular shape in contrast to the alpha-hemihydrate which are more dense and have a prismatic shape. When the alpha-hemihydrate is mixed with water, the pro dtrct obtained (dental stone or die stone) is much stronger and harder than that resulting from beta-hemihydrate (plaster). The chiefreason for this difference is that the afpha-hemihydrate powder (stone) reqrires much less gauging water when it is mixed than does the beta-hemihydrate. The beta-hemihydr^te Q)lqster) water to float its powder particles so that they can be stirred, because the crystals are more irregular in shape and are porous in character. Note: All glpsum products that are reacted with water form calcium sulfate dihydrate as a reaction Droduct.

Which of the following marginal designs is theoretically the best finishing margin for cast gold restorations allowing burnishing and adaptation of the gold to the tooth Shoulder Shoulder with a bevel Chamfer Bevel or feathered edge

Bevel or feathered edge However, in practice this finishing line is difficult to read on both the impression and die and may lead to inaccurate extension and also distortion ofthe wax pattem, and subsequent casting, as a result ofthe thin wax. It also offcrs the least margid.l strength to the casting- The chamfer prepamtion is the preferred linishing line for cast gold restorations. The resultant cast- ing has sufficient marginal strength; at the same time it allows the slidingjoint at its periphery to mini- mize the gap between the tooth and preparation, thus rcducing the thickness of the cement. A well-prepared chamfer margin combines the advantage of an easily definable margin, on both the im- pression and die, with minimal tooth prcparation. The shoulder preparation is the finishing line of choice for porcelain jacket and tll-ceramic crown preparations, The edge strength of porcelain is low; therefore, a butt joint is required. The shoulder provides resistancc to occlusal forccs and minimizes stresses in the porcelain. The margin can be easily read on both the impression and die. The main disadvantage is that any inaccuracies in the fit ofthe cro$n Nill be reproduced at thc margin, resulting in an increased thickness ofcement. Tle should€r with a bevel allows a sliding fit to occur at the margin and therefore may be used on thc proximalbox ofinlays and the occlusal shoulder ofthe mandibular three-quarter crowns ltmayalsobe used for the labial margins ofmetal-ceramic crowns. Providing these margins are gival crevice, little display ofmetal will be noted. Four Tlpes of High-Gold Alloys: Slass- placedjust in the gin- l. ADA t-ype I highest gotd content, 83o/o noble metals. Intended for small inlays. Easily bumished due to high ductility. 2. ADAtype II: nished. $eatcrthan 78olo noble metals. Intended for larger inlays and onlays. Can also be bur- 3. ADA type UI: greater than 75o% noble mctals. Intended for onlays and crowns Capable ofbeing heaFtreated. 4. ADA type Iv: greatcr than 7570 noble metals. Intended for bridges and removabJe partial dent- ures Also capable ofbeing heat-treated. Hardest ofhigh-gold alloys.

Hlaf closed eyes can increase the sensitivity of retinal rods to better choose the "value" of the color "Blue" fatigue accentuates "yellow" sensitivity. This means that if you look at blue color objects (drapes, charts, wall-color or any other object around,) while selecting the shade, it will help to accentuate the ability to discriminate yellow shades. The first statement is true; the second statement is false The first statement is false; the second statement is true Both statements are true Both stalements are false

Both statements are true Shade selection sequence: . . . . . . Use the same shade guide as given by the manufacturer Match the shade before you do any preparation ofthe tooth Remove all distractions (e.g., Iipstick, dark glasses, heavy make-up, etc.) Quick rubber cup and paste prophylaxis can make shade selection more accurate Position yourselfbetween the patient and the light source When observing, do not gaze for greater than 5 seconds at a time. Prolonged gazing decreases the ability to discriminate colors and shades . . Proceed by process of elimination. Exclude first, shades which are too light or dark Half-closed eyes can increase the sensitivity of retinal rods to better choose the "value" ofthe color Remember: "Blue" fatigue accenhrates "yellow" sensitivity. This means that ifyou look at blue color objects (drapes, charts, wall-color or any other object around) while se- lecting the shade, it will help to accentuate the ability to discriminate yellow shades.

Elastomers are rubbery polymers that are capable of elastic deformation from undercut arcas to produce a complete impression for dentate situations. Impression materials must have some strength, but generally their design is focused more on accuracy, dimensional stability, and flexibility (or tear resistance) The first statement is true; the second statement is false The first statement is false; the second statement is true Both statements are true Both statements are false

Both statements are true The simplest method ofclassifoing impression materials is by key properties: rigid' water-bas€d, and elas- tomeric. Of the rigid rlpes, impression plaster was the first material us€d for both edentulous and denolous imprcssions, it is no longer used for impressions. Impression compound is used for single tooth impressions where there are no undercuts. zinc oxid€ eugenol Water-brsed systems include alginate fil,"e1,ersible (ZOE) is used for edentulous impressions. lrydrocolloid) and ag^r-^g r (reversible hydrocolloid). Both types ofmat€rials are inherently unstable because wat€r is 85oZ ofthe composition. They are v€ry eas- ily distort€d during syn eresis (loss ofwaterfron the air). of$'ater to lhe air or surrounding envirokmenl) or ifibibition Elastom€rs are rubbery polymers that are capable ofclastic deformation fiom undcrcut areas to produce a complet€ impression for dentate situations. There are four major types pol),ethe\ and pol\'ri nll si loxane). Characteristics of elastomeric impression malerials: . Bas€: packaged as a paste in a tube, as a cartridge, or as putty in ajar (ahsorption (pollsullide, condensation silicone, . Catalyst: also kno$.n as lhe acceleratot is packaged as a paste in a tube, as a cartridge, or as a liquid . Forms of elastomeric imprcssion materials: . Light-bodi€d: also referred to as syringe q!e, or wash O?e. This material is used because ofits ability to flow in and about the details ofthe prepared tooth.Aspecial slringe, or extnrder, is used to place bodied material on and immediately around the preparcd tecth. . Regular and heavy-bodied: often referred to as tray-typc matcrials, they are much thicker As the names imply, they are used to fill the tray. Their stiffness helps to force the light-bodied material into close con- tact 1\ ith rhe prepared teeth and surrounding tissues to ensure a more accurate impression ofthc details of a prepamdon. Curing stages of elastomeric impression materials: . Initial set the first stage results in stiffening ofthe paste without the appeannce of€lastic prcperties. The marerial may be manipulatcd only during this first stage. . Final set: the second stage begins with the appearance ofelasticity and proceeds through a gradual change .o a solid rubberlike mass. The matedal must be in place in the mouth before the elastic properties ofihe llnal set begin to develop. . Final cur€i the last stase occu$ from I to 24 hours.

The anteroposterior curvatare (in the median plane) and the mediolateral curvatare (in the frontal plane) in the alighnment of the occluding surfaces and incisal edges of artificial teeth that are used to develop balanced occlusion is called: Curve of Spee Compensating Curve Curve of Wilson Curve of Pleasure

Compensating Curve The lorm ofthe compensating curve is entirely under the control ofthe dentist, For ex- ample, ifduring a try-in evaluation, a dentist notes that a protrusive excursion movement results in the separation of posterior teeth, the problem can be corrected by simply in- creasing the compensating curve. The value of the compensating curve is that it allows the dentist to alter the effective cusp angulation without changing the form of the manu- factued denture teeth. The function ofthis curve is to help provide a balanced occlusion. Not€: As the condylar inclination increases, the compensating curve must increase to keep a balanced occlusion. A prominent compensating curve is required when there is a steep condylar path associated wilh a low degree of incisal guidance. Orientation of the occlusal plane: The occlusal plane is an imaginary surface which is related anatomically to the cranium and which theoretically touches the incisal edges of the incisors and the tips ofthe occluding surfaces of the posterior teeth. lt is not a plane in the true sense ofthe word, but represents the mean curvature ofthe surface. The ante- rior point of the occlusal plane is determined by the position of the anterior teeth. The posterior determinants are anatomical lanalmarks -two-thirds the height of the retro- molar pads. Therefore, it is debatable as to the extent ofcontrol the dentist may exercise over the orientation ofthe occlusal plane. Cusp inclination is the angle made by the slopes ofa cusp with a perpendicular line bi- sectin-q the cusp, measured mesiodistally or buccolingually. This is under control of the dentist (choosittg j0" degree teeth or cuspless teeth, etc.). Remember: Anterior guidance in complete denture occlusion should be avoided to Drevent dislodsement ofthe denture bases.

With which of the following impression materials is it advisable to wait 20 to 30 minutes before pouring of models for stress relaxtion to occur Polysulfides Condensation silicones Polyvinyl siloxanes Polyethers

Condensation silicones These materials record surlace detail well and have excellent elastic arc less expensive ihan polyvinyl siloxanes fdddition Composition of condensation silicones: . . . . more lhan one cas! is poured . Slable ev€n ifpoured 24 hours after taking impresaion . Automix available Base: poly dimethyl siloxane propenies but a low tear strength. They silicones) ard polyethers. Cross-linking agent: alkyl ortho silicate or organo hydrogen siloxane Catalyst: organo tin compott ds (e.g., Fillers: silica or calcium carbonate titl octoate) \\'hv poor dimensional strbitity? The principal reaction, which takes place during setting ofthis material, is a condensation reaction and hence called condensation silicone. It occurs by elimin tior eth) l or methyl alcohol. This is also responsiblc for shrinkage ofthe material and resultant poor dimcnsional itabilit\'. l. Reaclion is sensitive to heat and moisture reduce working snd setting times). 2. Do not mix initially by haod f'eill . Most impr€ssion6 (allergic rcaction to catalyst may occur)

All of the following are characteristics of ZOE impression paste EXCEPT Dimensionally unstable Sets quickly Excellent detailed reproduction Sets hard No shrinkage even if store for many days

Dimensionally unstable This is fals€; ZOE impression paste is dimensionally stable ZOE impression materials were once very popular. Today, however, ZOE materials have been replaced by newer materials, such as polywinyl siloxanes, condensation silicones and poly- ethers. Components of ZOE impression paste: . Calcium chloride (CaCI): ftncttons as an accelerator ofthe setting time . Oil ofcloves: contains 70-850/o eugenol. It is sometimes used in preference to eugenol because it reduces the buming sensation in the soft tissues ofthe mouth. . Mineral or {ixed v€getable oil: plasticizer, aids in masking the action of eugenol as an irritant . . Resinous balsam: often used to increase flow and improve mixing properties Rosin: facilitates the speed of the reaction which results in a smoother, more homogenous mix The setting reaction that occurs is a typical acid-base reaction to form a chelate. This reaction can take place either in solution or at the surface of the zinc oxide particles. The chelate is thought to form as an amorphous gel that tends to crystallize, imparting increased strength to the set mass. . --.... 1. The dimensional stability ofa zinc oxide-eugenol impressionis most likely tobe ..'Note{,; ' ',i*tl: affected by failure to use a custom-made impression tray. 2 . The setting time of a zinc oxide-eugenol impression paste may be acc€l€rated by adding a drop ofwater to the mix. 3. The setting time of a zinc oxide-eugenol impression paste may be r€tard€d by adding inert oils (olive or mineral oils) during mixing. 4. Ifthe paste is too thin or lacks body before it sets, a filler----such as a wax or an inen powder (lanolin, kaolin, etc.) may be added to one or both of the original pastes

A 7/8ths crown is a 3/4 crown whose vertical: Mesiobuccal margin is positioned slightly distal to the middle ofthe buccal surface Distobuccal margin is positioned slightly mesial to the middle ofthe buccal surface Mesiolingual margin is positioned slightly distal to the middle ofthe lingual surface Distolingual margin is positioned slightly mesial to the middle ofthe lingual surface

Distobuccal margin is positioned slightly mesial to the middle ofthe buccal surface A partial crown is a cast restoration made entirely from metal and covers more than half but not all ofthe tooth's clinical crown. A partial crown is named according to the fractional amount ofthe clinical crown it covers. Examples are the half, three-quarters, foul- fifths, and seven-eighths crowns. In most instances, the facial surface ofthe tooth is not disturbed for esthetic reasons. The seven-eighths crown design is especially effective either as a single tooth or an abutment restoration on maxillary molar teeth where both proximal surlaces are involved as well as the distal buccal suface ofthe tooth. In many instances, the mesio-buccal cusps of maxillary first and second molars can be preserved for esthetics and still provide adequate extension to include extensive areas ofdestruction. Seven-eighths crown: . It can be used on any posterior tooth .Esthetics is good since the veneered distobuccal cusp is obscured by the mesiobuccal cusp . Distobuccal finish line is easy to access, which makes preparation easier to do. It also makes cleaning ofthe margins easier for the patient . . . \4ore coverage than the standard 3/4 crown which improves its resistance Especially useful when the distal surface has caries or decalcification Serves as an excellent abutment for a bridse

The first step in the treatment of abused tissues in a patient with existing dentures is to: Fabricate a new set of dentures Reline the dentures Educate the patient Excise the abused tissues

Educate the patient Important: The patient should understand both the cause ofthe tissue deterioration and the eventual outcome ifthe process is not arrested. Treatment plan for tissue r€cov€ry from abused tissues: . . Educat€ the patient Remove the dentures: at least for 24 hours or until the tissues retum to normal size, shape, color, consistency, and texture. Note: Ifthe constant wear ofunacceptable den- tures is the cause of the tissue abuse, the most efficient preliminary treatment is re- moval ofthe dentures. However, business and social commitments may not permit removal for extended periods. In such patients, resilient tissue conditioning materi- als may be used to assist in the tissue recovery program. . Have the patient clean the dentures: with a sofi brush and no abrasive agents. They should be instructed to soak the dentures for at least 30 minutes in a commercially available denture disinfectant solution. . Ifpatient has a Candida albicans infection (either generalized or angular cheilitis): should be treated by using nystatin oral rinses for generalized infection and nystatin h|ith tridmcinolone acetonide) cream for angular cheilitis. . Resilient tissue conditioning materials may be needed to assist in the tissue recov- ery program. Other procedures recommended as aids in the treatment ofabused tissues include mas- sage and warm saline rinses.

Dental plaster and stone are vibrated after mixing to: Minimize distortion Reduce setting time Eliminate air bubbles Increase the setting time

Eliminate air bubbles Using a vibrator when pouring models helps to eliminate ar bubbles (trapped air).This produces a more accurate, usable model. Another way ofpreventing entrapment ofair is to place the proper amount of water in the mixing bowl first and then sift the model plaster or stone into the bowl. When mixing dental plaster or stone, any ofthe following $,ill cause the gypsum product to set faster -incr€ased f.r/one) crystals! requires more spatulation, a lower water-pow- der ratio, and using a mixture of water and ground-up set g'?sum particles to mix with the plaster or stone. Once the impression is poured, it should be allowed to harden for 45 minutes to I hour (or until cool to the touch) before removing the cast from the impression. Casts can be disinfected by immersion in a l:10 dilution of sodium hypochlorite for 30 minutes or with iodophor spray. If nodules of stone appear in the occlusal pits ofa stone cast, it is most likely due to the entrapment ofair during the insertion and seating ofthe tray. lrJote: All types of gypsum products are weaker in tensile strength than compressive strength.

A chronically ill fitting denture may cause an inflammatory fibrous hyperplasia adjacent to its border known as Verrucous vulgaris Inflammatory papillary hyperplasia Stomatitis nicotina Epulis fissuratum

Epulis fissuratum The cleft-like lesions ofepulis fissuratum result primarily from overextension ofden- ture flanges. The overextension may result from long-term neglect or settling subsequent to residual ridge resorption. Trar.rmatic occlusion of natural teeth opposing an artificial denture may also cause this condition. Denture stomatitis is a localized or generalized chronic inflammation of the denture bearing mucosa. Clinically, there is redness and a buming sensation. There may be or mav not be discomfort. Trauma and secondary fungal infection appear to be the most likeh causes of denture stomatitis. The treatment generally consists of: 1. Improved oral hygiene 2. Tissue rest -1. -+. Antifungal therapy (ny*atin) Resilient tissue conditioners 5. New. well-fittins dentures

The primrry role of anterior teeth on a denture is: To incise food Occlusion Esthetics Stability of the denture

Esthetics Spaces, lapping, rotation, and color changes can bejudiciously used to create a natural appearance. Note: Proper lip support is provided by the facial surfaces of teeth and sirnulated attached gingiva. Setting the anterior teeth either too far lingually or facially to satisfy esthetic concems should not be done. When selecting teeth, pre-extraction records are very valuable. Maxillary and mandibular anterior teeth should not contact in centric relation. The outline ofanterior teeth should harmonize with the form ofthe face: . . Convex profile faces should have a similarly convex labial surface ofanterior teeth Broader contact areas ofteeth look more natural on dentures as they seem more compatible with advanced age Whistling when a patient speaks with dentures (complete or partial wltich replaces the incisors) may be caused by any ofthe following: . . . Vertical overlap is not enough Horizontal overlap is too much The area palatal to the incisors is improperly contoured (too high or too narroh,) Note: In general, functional needs overshadow those ofesthetics when selecting pos- terior teeth. Do not set mandibular molars over the ascending area ofthc mandible because the occlusal forces in the area will dislodse the mandibular denture.

Maxillary anterior teeth in a complete denture are usually arranged Facial to the ridge Lingual to the ridge Exactly over the ridge

Facial to the ridge (for best esthetics) Setting anterior teeth directly over the ridge usually causes poor esthetics of dentures. Also, it is important to have accurate adaptation ofthe border seal and adequate bulk of the maxillary facial flange for good esthetics. Vertical dimension ofocclusion affects the lip support as well. For most patients, the labial surface ofthe central incisor should be approximately 8 mm anterior to the center ofthe incisive papilla. The labioincisal onethird ofthe maxillary central incisors should support the lower lip when the teeth are in occlusion. Important: The long ares of the maxillary central incisors should be perpendicular to the occlusal plane; the long axes of the maxillary lateral incisors should have an asyrn- metric mesiodistal inclination. Remember: Maxillary central incisors are the most important teeth when esthetics is under consideration. Their placement controls the midline, speaking line, lip support and srniling line composition. Note: Placement of maxillary anterior teeth in complete den- tures too far superiorly and anteriorly might result in difficulty in pronouncing "f'and "v" sounds. Some ofthe common errors in the arrangement ofteeth include: . . . . Setting mandibular anterior teeth too far forward to meet the maxillary teeth Failure to make canines the tuming point ofthe arch Setting the mandibular first premolars buccal to the canines Establishing the occlusal plane by an arbiirary line on the face . Not rotating anterior teeth enough to give an adequately narrower effect

A generlized speech difficulty with dentures is usually cused by which two of the following Faulty tooth position Excess vertical dimension of occlusion Faulty palatal contours Faulty occlusion

Faulty tooth position Faulty palatal contours Spcech problcms due to faulty tooth position can be avoided by placing thc dcnturc tccth as close as to thc position ofthc natural tccth. Note: Thc most cffcctivc timc to lcst for phonctics is at thc timc oflhc wax try-in oithc t.ial dcrture frlrr rs l/s!d f thefourth appointmett). Faulty palatal contours can bc co.rcctcd by trial and crror Add wax to incrcasc contours and rcducc as nccdcd to improvc articulation ofsounds. Note: Paticnts who have becn eden- tulous for many years oficn havc more distorted spccch than thosc \r'ho havc bccn cdcntulous lbra shorllimc. This is usually duc to a loss oftonus ofthc tonguc musculaturc.

Aa small hook like projection of bone that extends from the medial pterygoid plte of the sphenoid bone is called Hamulus Hamular notch Maxillary tuberosity Fovea palatini

Hamulus (aka hamular process) *** It is a thin, curved process that serves as the superior attachment of the pterygo- mandibular raphe. This raphe is a tendon between the buccinator and superior constrictor rnuscles. The hamular notch is a thin cleft between the maxillary tuberosity and the hamulus. The vibrating line is an imaginary line drawn across the palate that marks the begiming of motion in the soft palate when an individual says "ah". It extends from one hamular notch to the other. At the midline, it usually passes about 2 mm in front ofthe fovea palatinae. Remember: The distal end ofthe maxillary denture must cover the tuberosities and ex- tend into the hamular notches. Overextension at the hamular notches will not be tolerated because of pressure on the pterygoid hamulus and interferences with the pterygo- mandibular raphe. When the mouth is opened wide, the pterygomandibular raphe is pulled forward. Ifthe denture extends too fff into the hamular notch. the mucous membrane cov- ering the raphe will be traumatized. The fovea palatinae are indentations near the midline ofthe palate formed by a coalescence of several mucous gland ducts. They are always in soft tissue, which makes them an ideal guide for the location ofthe posterior border ofthe denture.

Which ofthe following best describes "strain hardening" or "work hardening"? Hardening (or deformation) of a metal at room temperature Hardening (or deformotion) of a metal at a very high temperature Softening a metal by controlled heating and cooling Softening a metal at room temperature

Hardening (or deformation) of a metal at room temperature In polycrystalline metal, dislocations (defects) tend to build up at the grain bound- aries. Also, the banier action to slip at the grain boundaries causes the "slip" to occur on other intersecting slip planes. Point defects increase and the entire grain may eventually become distorted. Greater stress is required to produce further "slip" and the metal becomes stronger and harder. The process is known as strain hardening or work hardening. The latter term is derived from the fact that the process is a result ofcold work ( i.e., deformation at room temperature, in contrast to the effect of working at a higher temperature, such as in forging). hardening, with further increase in cold work, is fracture. The ultimate result ofstrain The phenomenon ofcold work and strain hardening is familiar to everyone. For example, one way to cut a wire is to bend it back and forth rapidly between the fingers. When all the slip possible has occurred, the wire fractures. Important: The surface hardness, strength, and proportional limit of the metal are increased with strain hardening, whereas the ductility and resistance to corrosion are decreased. However, the elastic modulus is not changed appreciably. .. , l.Under a microscope, elongated grains in the microstructure of a wrought 'rote*. wire indicate that the wire has been cold worked or strain hardened. '*-i.". 2. A slip is a deformation process requiring the simultaneous displacement ofan entire plane ofatom A, relative to the plane B, below it'

Dental plasatr is produced by Heating gysum in an open vessel at 150'C -160'C Heating gypsum under steam pressure in an autoclave at 120'C -150.C By boiling gypsum in a 30% aqueous solution of calcium chloride and magnesium chloride

Heating gysum in an open vessel at 150'C -160'C This process produces particles that are porous and inegularly shaped. Note: It is the weak€st gypsum product. Heating gypsum under steam pressure in an autoclave at 120'C - 150'C produces dental stone. This process produces particles that are uniformly shaped and less porous. Boiling glpsum in a 30o% aqueous solution olcalcium chloride and magnesium chloride produces high strength and strongest particles. liotel (improved) die stone. This process produces the least porous All gypsum products come ftom the mineral gypsum, which is the dihydrate form of calcium sulfate. During heating, (the manulircturing process), water is lost and g)?sum is converted to the hemihydrate form of calcium sulfate (p owder). When water is added to the powder, a chemical reaction takes place and the hemihydrate is converted back to the dihydrate form of calcium sulfate. ***The l. When mixing gypsum products always sprinkle the powder into the water. This results in better powder mixing and reduces the chance for air bubbles. 2.When gypsum products are mixed with water, heat is given ofl This is called an exothermic reaction. 3. Exposure ofa stone cast to tap water should be minimized because eroding ofthe cast will result.

The preparation for a full veneer crown is begun with occlusal reduction. There should be ? clearance on the functional cusps and about ? on the non-functional cusps. 0.5 mm; 1.0 mm L5 mm; 1.0 mm . 2.0 . mm; 1.5 mm 2.5 mm; 2.0 mm

L5 mm; 1.0 mm . Thjs reduction is done to eliminate undercuts and create space for suffcient metal to ensure adequate strength ofthe crown. Remember: In preparing a tooth for a metal-ceramic crown, it is necessary to create space for 0.5 mm ofmetalpfus at lcast 1.0 mm ofporcelain 1.5 mu) to cnsure adequate strength and optimum esthetics of the ceramic material. Snpporling (fuhctiotlal) cusps require 2 mm of the reduction The opposing walfs should convcrge no more than lO degtecs (6 degree tapet is reconmended). A chamfer lpreferably finish line /0.i l?r, and a1l maryins should be placed supragingivally when possible. The same amount ofoverall tooth reduction is needed for a metal-ceramic crown as for an all-cerarnic cro*n / L 5-2.0 nn). Howevet for all-cersmic restorations, the preparation needs to be well-rounded \\ irh no shrrp angles to avoid porcelain liacture. \ote: The most frequent causc of failure of a crown (reganlless ofa,hich ,*pe) is the lack of attention ro rooth shape, position, and contacts. Important: For gingival health, the conect contour ofinterprox- imal gingival areas and the gingival third are most important. Important: Gold is regarded as a more favorable material for the occlusal surface as its wear characreristics are more in harmony with enamel; porcelain is considered to bc the cause ofaccelerated wear of the opposing dentition. Gold would certainly be preferred for the restoration ofocclusal surfaces in rhe presence ofa tooth-grinding h.bit. .. l. Axial contours should correspond to the emergence prolile (usually flat or concave) of :{oteCl ja* the tooth. 2. The buccolingual dimension of a cast restoration is usually determined by the occlusal morphology oflhe opposing tooth. 3. Occlusal point contacts between opposing teeth arc preferred to broad, flat occlusal con- tacts to Dlevent weaf. 4. Type I and II gold alloys are uscd for inlays. 5. The most commonly used type ofgold for all-metal crowns and bridges is TyPe III.

Dr. Lozier requested that you mix alginate and take an impression, While measuring the water, you got involved in a conversation with your patient and did not notice how cold it was. This oversight will: Shorten the gelation time Make the mix unusable Lengthen the gelation time Not affect the gelation time

Lengthen the gelation time The best method to control the gelation time ofalginate impression materials is to alter the tempemture ofthe water used in thc mix. The higher the tempemture, the shorter lhe gelation timc, the lower the temperature, the longer the gelation time. The mix is usable regardless ofwater tem- penture as long as there is adequate ['orking tim€. Changing thc water/powder ratio and the mixing time will alter the gelation time, but thesc mcth- ods also impair ce ain properties ofthe matcrial. Too little ortoo nuch waterwill weaken the gel. Undermixing may prcvent the chemical action from occurring evenly; overmixing Inay break up the gcl. Calcium sulfate (/re reactol in alginate), is not so soluble in watcr that is entircly consumed be- fore gelation is con'lpleted. Therefore, the set mass becomes an entanglcment of calcium alginate fibrils around residual sodium alginate sol, filler and water. The residual sodium alginate has thc nasty habit ofreadily giving up water /.t),reresis) or gaining water thc cast should be poured imrnediately. (imbibitiotl). For accurate results, . L When taking an alginate impression fo. a partial denture, it is best to apply somc al- \ores ' ginate directly on the teeth to eliminate bubbles and saliva from the rest seat 2.lnaccuracies in imprcssions can be caused by fracture ofthe fibrils during gelation. .3. Tray adhesivc should ahvays be used to prcvent distortion at the time ofremoval. 4. The greater the bulk lhat the alginatc has, the more favorable the surface area:vol- ume ratio and the lower the susceptibility to water loss or gain and, therefore, unwanted dimensional change. 5. The tray sltould be removed 2 to 3 minutes after Selation. 6. The impression should be rinscd and disinfected with glutaraldehyde or iodophor befbre pounng. 7. Pouring with ADA type lV or V stone is recommended.

Before an accurate facebow transfer record can be made on patient, which of the following must be determined The inclination of each condyle Vertical dimension ofocclusion Centric relation Location of the hinge axis point

Location of the hinge axis point A face-bow is a caliper-like device used to record the patient's maxilla / hinge axis rela- tionship (opening and closing axis).It is also used to transfer this relationship to the ar- ticulator during the mounting of the maxillary cast. Ifthe face-bow tratsfer procedure is properly done, the arc ofclosure on the articulator should duplicate that exhibited by the patient. This hinge-axis face-bow transfer enables alteration in vertical dirnension on the articulator Note: When altering vertical dimension (either through restorations or with dentures), casts should be mounted on the hinge axis. When the maxilla,4ringe axis relation is transfened to the fully adjustable articulator, it may be necessary to obtain the precise tracing of the paths followed by the condyles. A pantograph is an instrument which carries out this task with the help of two face-bows. One is attached to the maxilla and the other to the mandible using a clutch that attaches the teeth in their resDeclive arches

A reverse 3/4 crown is most frequently fabricated for a Maxillary premolar Mandibular premolar Mandibular molar Maxillary molar

Mandibular molar This design preserves the lingual surface and is indicated for restoring mandibular mo- lars with damaged buccal surfaces and intact lingual surfaces. It is also useful on teeth with severe lingual inclinations where large quantities oftooth structure would be destroyed if a full veneer crown were to be used. The standard thre€-quarter crown is a partial veneer crown in which the buccal sur- face is left uncovered. It is the most commonly used form ofthe partial veneer crowns. A patient with a high cari€s index, short clinical crowns, and minimal horizontal overlap would not be a candidate for partial veneer crowns. The restoration ofchoice would be a full metal-ceramic crown, Note: R€tention and resistance forms in full coverage preparations on short molai:s can be enhanced by placing several vertical grooves or boxes.

Custom trays are an important part of rubber base impression techniques, since elastomers are: More accurate in uniform, thin layers 0.5 to 1.0 mm thick More accurate in uniform, thin layers 1.0 to 1.5 mm thick More accurate in uniform, thin layers 2.0 to 4.0 mm thick More accurate in uniform, thin layers 5.0 to 6.0 mm thick

More accurate in uniform, thin layers 2.0 to 4.0 mm thick With all elastomers, a custom tray should be fabricated with a plastic material. This tray should be rigid, have occlusal stops to avoid permanent distortion during polyrrerization and be coated with an adhesive. With hydrocolloid impre ssiors (ctlginate),a greater bulk of material produces greater accuracy, however, the thickness of rubberlike materials should not only be less, but should be evenly distributed. lmportant: Let adhesive that is applied to the tray dry completely. If it is wet, impression material may pull away. Custom trays are recommended for the following reasons: . . . . They require less impression materials They facilitate uniform concentration ofthe impression materials Stock trays usually are short in the llange area with stock trays, the uneven bulk of the impression material is conducive to distor- tion The accuracy and reliability of an elastic impression is controlled by the tray in which it is taken. The best tray is one that is custom-made for each patient. In most cases, it is best to take a complete arch impression, which will provide maximum reliability.

The popularity of agar impression material reversible hydrocalloid) is limited by the Difficulty in pouring the impressron Poor reproduction ofdetail Need for special equipment High cost

Need for special equipment The use of agar impression material does require special equipment. The rcproduction is excellent, and the im- pression is easy to pour compared to elastome c imprcssion mat€rial. Reversible hydocoltoid is an impression material that changes its back to a sol. Composition of reversible hydrocolloids: . . 85% water l2'.I5r/. agar *** (agar is an organic substance deri|ed Traces ofbomx fbr from physical state ftom a sol to a gel and then seaweed) rtrerglr), potassium snlfate (improves gvsum r&r/dce/ and sodium tetrabomte Conditioning bath for reversible hydrocolloid: . Three compartments: . The first bath is for liquefying the semisolid material. A specialwater bath called a "hydrocolloid conditioner" at212"F (100'C) liq\refies the material. After Iiquerying, the preset thermo- stat cools the tempcrature to 150oF automatically. . /65.5"C/ The second bath becomes a storage bath that cools the matedal, readying it for the impression. At this temperature, the tubes are waiting for use. . A third bath is kept at 110" F (43.3'C) for tempering the material aller it has been placed in the trav

All of the following are disadvantages to immediate denture therapy but which one is the MAJOR disadvantage Increased post-insertion care Increased post-insertion soreness Not being able to have an anterior tooth try-in to evaluate esthetics Greater complexity of clinical procedures A higher cost oftreatment

Not being able to have an anterior tooth try-in to evaluate esthetics Other drawbNcks of immediate dentures: .Increased post-ins€rtion care, including relining or remaking the denturcs. Contour changes occur in the healing residual ridge for 8-12 months. .Incrersed post-delivery soreness. The combination of post-extraction pain and denture related trauma often produces greater discomfoit during the first few days following insertion. . Greater compl€xity ofclinical procedures. Forexample, bordermolding and final impressions are more difficult when natural teeth remain. . Higher total cost of treatment Ther€ is an increased expense due to the need for relines and repeated equi- libration of the occlusion. Advanlag€s of immediate dentures: . Continuously acceptable esthetics. Immediate dentures are esthetically advantageous in that the palient is never without either natural or artificial teeth. . Improved speech adrption. Immediate dentures rcquire only one period ofspeech adaptation, whereas conventional denture trcatment requircs two; one afierthe teeth are extracted and anothcr after thc dentures are delivered. ' Protection of the extraction sites frcm trauma, Denhrres act as a typ€ ofbandage over the clot filled sock- ets. . Continuously acceptabl€ masticatory function. The patient retains some semblance ofchewing ability during the healing process. . Prevention oftongue enlirgement. When naiural teeth are lost and not replaced, the tongue tends to ex- pand into the available space. To help the patient get through the fiIst day ofwearing immediate dentures, instruct him to do the following: . Do not remove the dentures . Retum in 24 hours . Eal soft foods Recommended trvo-step schedule ottooth rcmoval; . First stepi extract all posterior teeth except a ma-rillary first prcmolar and its opposing tooth. This leaves a posrerior . "stop" in order to maintain the vertical dimension ofocclusion. Second step: after the posterior rcsidual ridges exiibit acc€ptable clinical healing, the second phase rreament, that ofdenture fabrication, can begin. The anterior teeth will be extracted at the time ofdcnnrrc lnsertlon.

AII of the following are resins used for fabricating provisional restorations EXCEPT Polymethyl methacrylate Polyethyl methacrylate Polyvinyl methacrylate Polyacryl methacrylate Bis-acryl composite resin Visible light-cured (VLC) urethane dimethacrylate

Polyacryl methacrylate Provisional restorations: Requirements: . . Provide pulpal protection Positional stability . . . . Occlusal function Easily clcancd margins Strength and retention Esthetics Resins for prorisional restorations: . . ' . polvmelhvl methacrylatc Polvcthyl mclhacrylatc Pollinyl mcthacrylatc Bis-acryl composite rcsin . \'isiblc lighccurcd /,/ZC) urethane dimethacrylatc \l€thods of fabric.tion: . Prefabricated: Uscd for single tooth restoration (e.g., anatonic netal crown t.roth ol orcd polr@rbonate crovns). fon,$, deu celuloid shells and . Custom-made: uscd for single and multi -unit lixed b.idges-There are a variety of tcchniqucs for f'abricating thc mould used to form the outcr surface ofthc custom provisional rcstoraljon /i.e., take an inpression prior to prcpar- ing te€th fiIh algilnte. elastomenc i tpression material or use tle .liagnostic &st ond clear lhetmoplastic resi natrix [wcuunt fon'ing machineJ).The innc' s[rface will be Provisional restorations can be classified by the t€chnique olfabrication used: . providcd by the preparation. Direct technique: is done on the actual prepared leeth in the mouth. Disadvantagcs includc: potcntial tissuc trarma, poor marginal fit, and prolonged chairside time. .Indirecttechnique: is done on the cast outside thepatient's mouth. Advantages include: no tissuc fauma, good marginal fit, and minimum chairsidc timc. . Combination techniqte (inrlirect-direct): advzntages include: reduced tissue trauma, rcasonablc marginal fit, and reduced chairside timc. Note: Thc provisional rcstoration is cemcntcd in with Temp Bond.

Which impression material is very stiff which makes it very difficult to remove without rocking Irreversible hydrocolloids Polysulfides Polyethers Condensation silicones

Polyethers Polyether materials are dimensionally unstable in the presence of moisture. These materials are the most rigid frt,r?s, and most dillicult to remove fiom the mouth. Note: Whcn removing the impression, break the seal and rock slightly to prevent tearing. Composition of polyether impression materials: . . . . *** Base: amiDe teminated polyether polymer Cross-linking agent: an alkyl-aromatic sulfonate Catalysrs: glycol-based plasticizers Filler: colloidal silica Polyeth€$ are two-component materials. The base includes apolyether, silica filler and a plasticizer The accelerator contains a crossJinking agent. When mixed, a nrbber is formed by a cationic polymerization process. Cationic polymerization is very similar to addition polymerization, except that instead ofa free rad- ical, a cation fporirlyc ior, is the reactive molecule. \o reaction by-product is produced. Polyethers have ex- cellent dimensional stability. They ar€ also t.uly hydrophilic, resulting in superior wettability.Important regarding polyeth€r impr€ssion materials: \\'arer, saliva, and blood affect polyether matenal Added moistur€ will increase the impression's marginal discrepancy

The powder used in mixing acrylic resin is referred to as the: Dimer Initiator Polymer Monomer

Polymer Components of Acrylic Resins: .Powder: . fdt rre lalest, some literature sals 45 min' Pofymethyl meth,,cryl^te (PMMA) polymer, benzoyl peroxide initiator, and Liquid: Pure methyl methg,cryl^te (MMA) monome., hydroquinone inhibitor, crosslinking agents, and ch€mical activator about polymerization. fdi pigments. methrl-ploluidine). Not€: This activator is only present in self_cured resins to bring Remember: mechanical properti€s of resins are influenced by the following: pollmerization and the harder the resin) . . Molecufar weight of the polymer (the grealer the molecularweigllt, the betler the Degree of cross-linking (need difunctional monomers which contain tu)o areas proportional to lhe degree ofpol)rnerization. A polymer with a crosslinking occurs. . : Tle composition ofthe mororner ( prepares lhe '. - - .. . polymer) for reaction) is direclly greatcr molecular weighl is formed if more 1. Acrylic resins will expand when immersed in water and become distorted when dried out :NoteJ;2.shrinkageofanacrylicr€sinoccu$but€xcessiveshrinkagemayoccuriftoomuchmonomer , i ..&1 tliqurll is added to the polymer lpov'derJ. The volumetric monomer-to-polymer ratio is l:3. 3. The polynrerization reaction of methyl methacrylate is €xothermic -gives 4. Inhibitors are added to the monomen to aid in preventing polymerization during storage. 5. Cross-linking contributes greatly to the strength ofthe polymer 6. H€al-cured materials: heat is used as an accelemtor to decompose benzoyl peroxide frre polymerization ofMMA into PMMA Th€ pol]'rnerization process continues as new PMMA is formed as a matrix around residual PMMA t alol) into fre€ radicals, These fiee radicals initiate the powder particles. 7. Self-cured (auto-cured, tofuidine flvri., out heat cold cureA materials: a chemical activator such as dimethyl-p_ is a lertiory amine) is ?dded to the monomer causes decomposilion of the b€nzoyl peroxide (lhe fMM,'r' This chemical activator initiator) into free mdicals. These f.ee radi_ cals initiate the polymerization ofMMA and PMMA. Tle polymerization process continues the same as in heat-curing materials. 8- The pofymerization range is the temperaturc mnge, approximately 60"C (l1f F) to 77"C f17rP-F), at which the major part ofpollmerization occurs in a heat-cured resin. 9.The heat-cured resins have less residual monomer and a higher molecular weight than the self- cured resins; therefore, they are stronger. They also have superior color stability.

The shape and amount of the distobuccal extension of a complete mandibular edentulous impression is determined during border molding by the: Ramus of the mandible Position and action of the masseter muscle Lateral pterygoid muscle Tone ofthe buccinator muscle Size and location of the buccal frena

Position and action of the masseter muscle When border molding a mandibular custom tray that will be used for a final dmture impression: . . . The distobuccal extension is determined by the position and action ofthe masseter muscle. The distolingual extension is limited by the action ofthe superior constrictor muscle. The buccal vestibule: proper extension into this area provides the best support for the mandibular denture. This area is refened to as the buccal shelf. . Lingual frenum: the proper borders must be established with movements ofthe tongue when bor- der molding. The genioglossus muscle influenc€s the lengdr ofthe flange during normal movements of the tongue. . The mentalis muscle will elevate the mandibular ant€rior labial arer unless this border is estab- lished by accurate border molding. . The retromol.r pad: marks the distal termination ofedentulous ddge. This structure needs to be cov- ered for support and retention. . The mylohyoid area: the flange in this ar€a must accommodate the movem€nt ofthe mylohyoid muscle in swallowing. . The retromylohyoid area: this area is limited posteriorly by the action ofthe palatoglossus muscle and inferiorly by the lingual slip ofthe superior constrictor muscle. Remember: The palatoglossus, superior pharlalgeal constrictor, mylohyoid, and genioglossus muscles are influential in molding the lingual border ofthe mandibular impression for an edentulous patient. Import.nt: The most important consideration in checking custom trays for accurate border molding is stability and lack of displacement. Note: The custom tray for a final mandibular or maxillary complete denture impression should have a sprcer with stops to insule that th€ tray will be seated in proper relationship to the arch and that there will be adequate room for the impression material. The space is created with wax covered by aluminum foil over the master cast pdor to forming the tray. The primary difference between border molding with a ZOE impression matcrial and border molding with modeling plastic is that the zoE impression material must be border molded during one inser- opposed to two insertions with modeling comoound. tion and within the setting time of the mate al -as

Polysulfide impression mater should be Poured immediately Poured within 15 minutes Poured within 30 minutes Poured within 1 hour

Poured within 1 hour Polysulfides have good flow properties and high nexibility and tear str€ngth. These materials show the strongest resislance to tearing, but as a result, impressions can distort when removed from areas where deep undercuts are prcsent. They have a long working time and a relatively long polymerization time, which may add to patient discomfort. Their rcsistance to deformation is low. Generally, the use ofthis material demands the construction ofa specialllray (custom tray) in order to control polymerization shrinkage by thc use ofa uni- form thickness ofimpression mat€rial. Note: The polymerization ofpolysulfides is exothermic and is acccl- erated by an increase in the temperature or humidity. Composition of polysulfide impression material: . Base: mercaplan firnctional polysulfide . . . . . Cross-linking agent /dccelerator): stJlfur andlor lead peroxide Plasticizer: dibutyl phthalate Catalyst: lead dioxide, copper hydroxides, zinc percxide or organic hydroperoxide Fille(to add strength): titanium dioxide or zinc sulfate Retardei oleic or steric acid Notes: (l) Tle lead dioxide is responsible for the broum color and difficulty in cleaning clothes that come in contact with this impression mat€rial(2) On polymerization water is releas€d as a b)?roduct causingdi_ mensional contmction. The cast must be poured within I hour

Which type of dental ceramic is the best in mimicking the optical properties of enamel and dentin Predominantly glass Particle filled glass Polycrystalline

Predominantly glass Metal ccramic restorations have been available for more than three decades. This type ofrestora- tion has gained popularity from its predictable perlomance and reasonable esthetics. Despite its success, the demand for improved esthetics and the concems regarding the biocompatibility ofthe metal has lead to the introduction ofall-ceramic restorations. Two concepts help in simplifying the understanding of dental ceramics: First, ceramics fall into three main composition categoriesl . Predominantly glass . Particle filled glass . Polycrystalline Second, ce.amics can be considered as a composite material, in which the matrix is a glass that is lightly or heavily filled with crystalline or glass particles. Predominantly glass: have a high content ofglass making this type of dental ceramic highly es- thetic. This type is the best ir mimicking the optical properties ofenamel and dentin. Optical ef- fects are controlled by manufactures by adding small amount of liller paniclcs. Particle-filled glass; filler particles are added to the glass matrix to improve the mechanical propenics. Fillcrs can be crystalline particles ofhigh-melting glasses. Polycrystalline: this type ofce.amic contains no glass. Atoms are packed into regular crystalline arrangement making it toughcr and less susceptible to crack propagation. lt is important to under- stand the lact that highly esthetic ceramics are predominately glass, and ceramics that exhibit high strength are generally crystalline. Note: It is important to understand the fact that highly esthetic ceramics are predominately glass, and ceramics that exhibit high strength are generally crystalline.

At the first appointment after insertion of complete dentures the presence of generalized soreness on the crest of the mandibular ridge is most likely due to The newness of the denture Defective tissue registration Premature occlusal contacts lncornplete polymerization of the denture base

Premature occlusal contacts At the first appointment after insertion ofcomplete dentures, the presence olgeneralized soreness on the crest of the mandibular ridge is most likely due to improper occlusion (premature occlusdl contqcts). To identify these, the best method in the mouth is to use disclosing wax that is slightly warmed. Insert the wax bilaterally and bave the patient close into centric. The prematurities will show up as windows in the wax' Once centric is complete, be sure to check eccentric movements. Important: Acrylic spicules, inaccurate denture bases and trapped food can all cause ul- cers as rvell. Ifan acrylic spicule is found, it should be reduced. Ifan inaccurate denture base is suspected, it should be relined. r - . - 1. After relining dentures, ifa patient constantly retums for adjustments due to ;:.iot{] sore spots on the ridge, check the occlusion. The relining procedure may have '@f Maxillary & Mandibular ircisots or p.emohrs conta.t during sibilsnl /r s/,, z cr) Cliniciar obs€'ves that incisal €dg6 of naxillart incisors co act lhe lower lip I mm or moE labial to lhe wet/dry of lower lip when "F & "1f'lomds are nade changed the centric relation contacts. 2. Errors in occlusion may be checked most accurately by remounting the dentures on the articulator using remount casts and new interocclusal records. Remember: Casts mounted with an interocclusal record are mounted more ac- curately if the material used is selected according to the accuracy of the casts bing articulated (casts produced with iteversihle hydocolloid are more accurateb) mounted with wtu records, and casts obtained with elastomeric materi' sls are more accurately mounted with elsstomeric registration materials or zinc and eugenol paste).

Which luting agent (cement) has the lowest solubility Zinc phosphate Zinc polycarboxylate Glass ionomer Resin-modified glass ionomer

Resin-modified glass ionomer l. Cemenrs do not rdd to the retentive chamcteristics ofa crown. Ccmcnts act by increasing the frictional rcsistance between tooth and restoration. Thc ccmcnt though they do not prcvcnl onc surtacc from bcing liftcd from another prcvcnts two surfaccs from sliding. Al- 2. A toolh should bc wiped dry before cementation ofa crown as opposcd to drying the tooth with alcohol and warm airto dccrease the possibility ofpulp damagc. 3. Always apply cement to both the rcstoration and tooth. 4. One way to rcducc thc potential for post-cementation sensitivity with zinc phosphate and ionomcrccmcnts is to use a resin based descnsitizeron thc 5. Cement film thickncss is dependent upon gencratcd dunng seating of the casting. prcparcd tooth p.ior to luting. powder-to-liquid ratio, powdcrparticle sizc, and pressure

All of the following are morphological changes associated with the edentulous state EXCEPT Deepening of nasolabial groove Loss of labiodental angle Retrognathic appearance Decrease in horizontal labial angle Narrowing of lips Increase in columella-philtral angle

Retrognathic appearance (a prognthic appearance is associated with an edentulous state) It must bc emphasized that one or more of these items are also frcquently encountered in per- sons with intact dentitions because the compromised facial support of the edentulous state is not the cxclusive cause of thc morphological changes. Patient's weight loss, age, and hcavy tooth attrition manifest orcfacial changes suggestive ofcompromised, or absent, dental support for the overlying tissues. Pre-extraction guides for selecting afiificial teeth from edentulous patients include: . . Photographs: provide general information about width and possibly outline fonn. Diagnostic casts: the form of the teeth can be very well judged casts ofnatural teeth , . if available (check with the patient's prerious dentist). from previous diagnostic Intra-oral radiographs: the size and form can be d€termined but beware because radi- ogmphs can be distorted and usually are larger images ofthe tccth. . The teeth of close relatives: when no other means are available to get an idea about the form, size and shade of teeth to be used for thc denture of an edentulous patient, records of son's or daughter's teeth can give a clue. lt may also help in the arangement ofteeth as well . Extracted teeth: sometimes patients keep their cxtracted teeth, which could be an excellent source and aid to delineatc the form ofthe teeth, thus helping in the selection 1. Degenerative joint disease is frequently scen in denture wearen but this may be age related rather than the state ofthe dentition. 2. The recording of centric relation is considered as an essential starting point in the design ofthe artificial denture. 3. ln complete denture prosthodontics the position ofthe maximum planned in- tercuspation of teeth or centric occlusion, is established to coincide with the pa- tient's centric relation.

The treatment plan for a patient indicates that both manilibular and maxillary immediate dentures are to be fabricated. The ideal way to do this is: Fabricate the maxillary immediate denture first Fabricate the mandibular immediate denture first Fabricate the maxillary and mandibular imrnediate dentues at the same time

The main reason for this is to avoid setting the maxillary teeth to the likely malpositions of the remaining mandibular teeth Important: Ifthe master casts are altered in an immediate denture procedure (e.g., elimination ofgt"oss undercuts), it is advisable to construct a second denture base that is trans- parent (called a surgicol stent or template). This surgical stent is placed over the ridge after the teeth are exhacted. Pressure points and undercuts are readily visible and surgical ridge conection can be performed. Remember: The duplication ofthe master cast used for the construction ofthe surgical template to be used at the time of immediate denture insertion is best rnade after wax elimination and after the cast is trimmed. Note: A major advantage with immediate dentures is being able to duplicate the position of the natural teeth.https://www.insider.com/actors-who-should-play-batman-2017-11#timothe-chalamet-is-the-right-age-and-has-the-right-demeanor-to-play-a-young-caped-crusader-2

The primary indicator of the accuracy of border molding is Adequate coverage of tray borders with the material used for border molding Contours ofthe periphery similar to the final form of the denture Stability and lack ofdisplacement of the tray in the mouth Uniformly thick borders of the periphery

Stability and lack of displacement of the tray in the mouth The ease and accuracy ofthe border molding depends upon: l. An accurately fitting cuslom tray 2. Control of bulk and temperature ofthe modeling compound 3. A thoroughly dried tray The custom tray fabricated on the preliminary cast is trimmed approximately 2 rnm short of the mucosal reflection and frenae. This is done by first checking the borders in the mouth and then trimmed down. This will allow a uniform thickness of 2 mm of model- ing compound when borders are molded. Proper border molding results in contours re- sembling the final form ofthe denture. However, the primary indicator ofthe accuracy of border molding is the stability and lack ofdisplacement oftray in the mouth. Border molding is completed in two stages. In the lirst stage the molding should ap- proximate the borders but should be slightly overextended. Excess compound is trimmed from inside and outside ofthe tray. The remaining modeling compound is then refined by repeating the process. The final form ofthe border molding should represent an accurate impression ofthe peripheral tissues. The modeling compound should have a smooth, al- most polished appearance. After border molding is cornpleted, some areas ofthe modeling compound should be re- lieved because the tissues are extremely displaceable and have probably been distorted during the border molding process. These areas include around the maxillary labial frenum and over the retromolar pad areas. Remember: Modeling compound *** (plastic) has a relatively low thermal conductivity.

Periodontal health of the gingival tissues is a major concern when phnning any fixed prosthodontic treatment. For optimum periodontal health, restoration linish lines should be: Within the sulcus at least 1.0 mm and away from the free gingival margin without encroaching on the biologic width Terminated at the free gingival margin Supragingival whenever possible (at least 0.5 mm from the free gingival margin) to allow for hygienic cleansing As far as possible subgingivally into the attachment apparatus

Supragingival whenever possible (at least 0.5 mm from the free gingival margin) to allow for hygienic cleansing There is general agreement among dentists and researchers that optimum fixed pros- thetic restorations will display supragingival finish lines. Such positioning is quite often not possible because ofesthetic or caries considerations. Subsequently. the margin must be placed subgingivally. Ifa margin needs to be placed sub- gingivally, the major concem is not to extend the preparation into the attachment apparatus. Ifthe margin does extend into the attachment apparatus, a constant gingival irritant has been constructed and ultimatety the crown will fail. In this case, the tooth should have had crown lengthening performed on it prior to final crown preparation. Rememb€r: It is important to maintain the biological width (the combined width of the connective tissue attachment and thejunctional epithelium, which averages approximately 2 mm). The most important criterion for a gingival margin on a crown preparation is that its position is easily discemible -must be able to recognize it easily. Note: The most com- mon complaint oflab technicians regarding a PFM prosthesis is improper margins in the impression. Rememb€r: The optimum margin for a casting is an acute edge with a nearby bulk of metal. This acute edge or angle can be easily bumished to improve its fit. Note: A butt joint, as gpified by a shoulder, is the poorest type offinish line that can be used with cast metal restorations.

The strength of a solder joint is proportional to its Porosity Thickness Surface area All of the above

Surface area Soldering is used in dentistry to connect bridgework and in fabricating orthodontic ap- pliances. Gold solders are generally used for fixed bridgework and silver solders for orthodontic appliances. It is important that the solder melt at least 150oF below the fusion temperatures ofthe metals or alloys being solders (for obvious reasons). A good solderjoint between 2 castings requires clean surfaces and fr€e electrons present on the surfaces. Commonly used dental solders include: Note: The bonding ofthe solder is contingent upon wetting ofthejoined surfaces by the solder, and not upon melting ofthe metal components. Cleanliness is the most important prerequisite ofsoldering, since the soldering process depends upon wetting ofthe surfaces to achieve bonding. Fluxing is the oxidative clean- ing ofthe area to be soldered. Fluxes are used to dissolve surface impurities and to pro- tect the surface from oxidation while heating. Note: Fluxing is also performed on molten metal alloys during the casting ofa crown or partial denture framework.

All of the following are true concerning a facebow or a facebow transfer EXCEPT The face-bow is a caliper-like device used to record the patient's maxilla,/hinge axis relationship (opening and closing axis) If the transfer is done properly, the arc of closure on the articulator should duplicate that exhibited by the patient The face-bow transfer is a maxillo-mandibular record The face-bow transfer is used to transfer the maxilla/hinge axis relationship to the articulator during the mounting of the maxillary cast

The face-bow transfer is a maxillo-mandibular record This is false; it is a record used to orient the maxillary cast to the hinge axis on the articulator. Several varieties of arbitrary face-t ows are available. All are based on an average lo- cation ofthe hinge axis and will yield an enor of2 mm or less in the majority ofpatients. Arbitrary rotational centers are generally located over measured points on the face or by some type of earpiece. One average measurement (above picture) places the rotational point 13 rnm anterior to the distal edge of the tragus of the ear' along a line from the superior-inferior center ofthe tragus to the outer canthus of the eye. The condylar styli of the face-bow are then placed directly over the dots.

Aall of the following statements regarding metal ceramic restorations are true EXCEPT The metal and porcelain must have compatible melting temperatures as well as compalible coefficient of thermal expansions The metal's melting temperature should be at least 300-500"F higher than the fusing temperature of the porcelain The metal coping should preferably have sharp surfaces to prevent shrinkage of the porcelain In function, glazed porcelain on the occlusal surface removes 40 times as much ofthe opposing tooth structure than gold

The metal coping should preferably have sharp surfaces to prevent shrinkage of the porcelain This is fals€; the metal coping must have all of its surfaces smooth and rounded to prevent porcelain shrinkage. Note: The purpos€ ofthe metal coping is to ensure the fit ofthe crown and to maximize the strength ofthe porcelain veneer. Important points to remember conceming the metal coping or substructure ofa metal-ce- ramic ctown: l. The metal must have proper thickness (0.5 mn) - very important 2. The outerjunction ofporcelain to metal should be at a right angle (to oJ the metal and subsequent f-acture of the porcelain). 3. All ofthe porcelain should be supported by metal. When deliv€ry cast restorations, the following sequence should be used: (l) check the in- temal surface fit (2) adjust the proximal maryinal integ ty (4 contacts and pontic-ridge relationship (3) avoid burnishing )check the stability (ifit is a bridge) (5) check the axial contours and last but not feast, (6) check the occlusion (centric qnd eccentrtic contacts). Important: If your margins were all closed at the metal try-in appointment and when the crown came back from the lab they are all open, check the contacts. They are probably too ttght (over-bulked ' ' . -. porcelain). I . Porcelain that is baked onto a high-fusing gold alloy may exhibit a green discol- ;'Note{ oration due most likely to contamination of the metal by copper traces. W 2. The best measure ofthe potential clinical performance ofa casting alloy is its ADA c€rtification. check the

What type of pontic design would you use on a patient with a high esthetic demand when preparing teeth numbers 9-11 for a fixed partial denture The saddle-ridge lap pontic The sanitary (hygienic) pontic The modified ridge-lap pontic An ovate pontic A conical pontic

The modified ridge-lap pontic The pontic is the suspended member ofa fixed bridge that replaces a missing tooth. This tooth substitute must provide patient comfort, convenient contours for hygiene, and be esthetic, if indicated. Most Common Pontic Designs: . The sanitary @1,glenic) pontic design leaves a space between the pontic and the ridge. Is most commonly used where esthetics are not important terior mqndible). Convex in all areas. . (nonqppearance zone, pos- The saddle-ridge-lap pontic design looks most like a tooth. Covers the ridge labiolingually with a large concave contact. Impossible to clean, should not b€ used. . The modified ridgeJap pontic design uses a ridge lap for minimal ridge contact. Gives the illusion ofbeing a tooth, but possesses all convex surfaces for ease ofclean- ing. This design is the one of choice for pontics in the appearance zone (where es- thetics are important) for both maxillary and mandibular bridges. Conical pontic: rounded (rop) and conical (bottom). Suited for molars without esthetic requirements (in non-appearance zone). Olat€ pontic: a sanitary substitute for saddle-ridge-lap design. Set in the concavity ofthe ridge hllicl is eilher ptesent or surgically made)that gives the appearance that it is growing from the tooth. Remember: The faciolingual dimension ofthe occlusal portion ofpontics is determined b1 the faciolingual position ofthe opposing centric holding contact areas

All of the following statements concerning pontics are trae EXCEPT one. With regard to the ease of cleaning and good tissue health; proper pontic design is more important than the choice of material used in fabricating the pontic The contour and nature ofthe pontic contact with the ridge is very important The area ofcontact between the pontic and the ridge should be small The portion ofthe pontic approximating the ridge should be as concave as possible . The pontic should exert no pressure on the ridge (passive contact with no blanching ofthe tissue)

The portion ofthe pontic approximating the ridge should be as concave as possible . This is false; the portion ofthe pontic approximating the ridge should be as conv€x as Pontic design and selection directly impact periodontal health. Pontics should contact kera- tinized attached tissue and rest passively, free ofpressure, to prevent ulcerations and plaque buildup. Pontic designs with concayities (such as the saddle-shaped pontic), are difiicult to clean because oftbe depression on their inner surface is inaccessible to conventional methods oforal hygiene. Egg- or bullet-shaped pontics are the easiest to clean because they are convex in all aspects and contact the residual ridge at a single point. Most important: Whatever pontic is used, it must be properly designed to prev€nt an un- healthy response to the underlying ridge mucosa. The pontic must: . . . . . . Be nonporous, smooth, and have a polished surface Make passive pinpoint contact with the gingival tissue Not be concave in two directions Be readily cleanable by the patient Be narrow€r at the expense of the lingual aspect of the ridge Be on as straight a line as possible between the retainers to prevent any torquing ofre- tainers or abutnents. Important: Excessive tissue contact has been cited as one ofthe major causes of failure of fixed bridges. Glazed porcelain, polished gold, unglazed porcelain, and polished acrylic are prefened in that order for their acceptability to the soft tissue.

When treatment planning for fixed prosthodontics The length of the abutment teeth can be accurately gauged The true inclination ofthe abutment teeth will be evident The presence of periodontal pockets and the crown-to-root ratio of potential abutment leeth Mesial,Distal drifting, rotation, and faciolingual displacement of potential abutment teeth can be clearly seen

The presence of periodontal pockets and the crown-to-root ratio of potential abutment leeth *** Important: The presence ofperiodontal pockets and the crown-to-root ratio ofpotential abut- ment teeth cannot be determined by studying diagnostic casts. You need to do an exam and have x-rays in order to obtain this information. More information that can be obtained by studying the diagnostic casts: . It allows an unobstructed view ofthe edentulous areas and an acaurate assessment ofthe span length, as well as its occlusogingival dimension. . The curvature ofthe arch in the edentulous region can be determined, so that it will be possible to predict whether the pontic(s) will act as a lever arm on the abutment teeth. . A thorough evaluation ofwear facets, their number, size, and location is possible when they are viewed on casts. Excessive wear on occluding surfaces ofteeth usually results from a dishar- mony between centric occlusion and cenhic relation. *** 1. lrreversible hydrmolloid or alginate is the material ofchoice to produce diagnos- tic casts. 2. Tray adhesive should always be used to prevent distortion at the time ofremoval. 3. The greater the bulk that the alginate has, the more favorable the surface area:vol- ume ratio and the lower the susceptibility to water loss or gain and, thercfore, unwanted dimensional change. 4. The tlay should be removed 2 to 3 minutes after gelation. 5. The irnpression should be rinsed and disinfected with glutaraldehyde oriodophorbe- fore pouring. 6. Pouring with ADA type IV or V stone is recommended. 7. Do not disturb poured impressions until they are set, the time varies between 30 and 60 minutes depending on which type ofstone is used.

All of the following are indications for porcelain veneers EXCEPT one Coverage of labial surface defects - hypoplasia of the enamel Masking of discolored teeth -tetracycline staining, discoloration following loss of vitality The severe imbrication of teeth Repair of structural damage - fractured incisal edges Improvement of tooth contour - peg-shaped lateral incisors Reduction of spacing in cases when orthodontics would be inappropriate

The severe imbrication of teeth (that is a contrindication to porcelain veneers) Other contraindications to porcelain veneers include: traumatic occlusal contacts, un- favorable morphology, insufficient tooth structure, and insumcient enamel. Technique for Insertion of Porcelain Veneers . The veneer should be tried in wet with either a drop of water or glycerine to check for fit. A reliable estimate for the possible post-cementation appearance with try-in pastes can also be performed. . The veneer fit surface should be cleaned to rernove any saliva contamination or try- in composite . Ifthe fit surface has not previously been treated with silane and protected with light- cured unfilled resin, this should be done at this stage . The enamel surface should be cleaned with pumice and water . While protecting adjacent teeth with matrix strips, the enamel is acid-etched with di- luted hydrofluoric acid. Note: The etched surface is washed and dried and a layer of unfilled bond resin is applied and thinned with oil-free air An appropriate shade oflight-cured composite is applied to the fit surface ofthe veneer which is "puddled" into place on the tooth surface . . . Gross excess of composite should be removed and light-curing completed Remaining excess composite is removed with finishing diamond burs, discs, strips, etc., and the margins finely polished . The patient should be seen in approximately one week

The most common cause of dry mouth (xerostomia) is Aging Alcoholism Vitamin A or Vitamin B deficiency The use of drugs to manage chronic diseases Diabetes

The use of drugs to manage chronic diseases Xerostomia is a possible side effect associated with more than 400 drugs including anti- hlpertensives, antidepressants, antihistamines, bronchodilators, anticholinergics, and sedatives. Mouthwashes, alcohol, tobacco, and caffeine may alter salivary flow or cause dryness ofthe oral mucosa. Even though xerostomia is not a disease, it can be a symptom ofcertain diseases. It can cause health problems by affecting nutrition as well as psychological health. It can con- tribute to and increase the chances ofhaving tooth decay and mouth infections. Temporary relief may be found from several sources: . . . . Saliva substitutes Sugarless hard candies Glycerine-based cough drops and lemon flavored glycerine mouthwash Medications may be added, changed, or dosages altered to provide increased salivary florv Remember saliva has several important functions: . . . . . . . \vashes away food debris and plaque from the teeth to help prevent decay Limits the growth ofbacteria that cause tooth decay and other mouth infections Bathes the teeth and supplies minerals that allow remineralization ofearly cavities Lubricates foods so they may be swallowed more easily Provides enzymes that aid in digestion Helps us enjoy foods by aiding in the "tasting" process \'loistens the skin inside the mouth to make chewing and speaking easier

Which of the following is the most important reason for treatment of hyperplastic tissue before construction of complete or removable partial denture It will make the patient feel better . It will make the face-bow transfer easier to perform To provide a firm, stable base for the denture The final impression material will flow better

To provide a firm, stable base for the denture Treatment may include: . . . . Tissue rest Soft reline ofexisting dentures Change in denture habrts (not wearing them 24 hours a dav) Surgical removal oftissue (y'ti.rsaes changes are extensive) Note: Mandibular tori, sharp pron.rinent mylohyoid ridges, and epulis fissuratum should also be evaluated for surgical removal trefore the iabrication ofnew dentures is begun. Curent concepts of impression making for complete dentures recommend using a technique that: . Affords placement and control ofthe impression material in recording border tissues (bonler molding) . Results in minimal displacement oftissues under the dentLre (registers the tissue in Its passive position) . [s dependent on the oral conditions present. \ote: The best impression technique for a patient with loose hyperplastic tissue is to reg- ister the tissue in its passive position. There must be intimate contact of the impression material with the tissue.

There are four types of gypsum products approved for use in dentistry. Which is rarely used Type I Type II Type III Type IV

Type I llTe lf Gyps[rn: "Modeling Plastca' . ' . Comprcssion strength: 1300 Pcrccntagc of cxpansion: 0.307; Uses: orthodontics diagnostic casts Type lll Gypsum: "Dcntal Stone" . . . Compression strcngihr 3000 Pcrccntagc ofcxpansion: 0.20% psi psi Type I Gypsum: 'lmprcssion Plastca' . . . Comprcssion strcnglh: 580 psi Pcrccntagc ofcxpansion: 0.15% Uscsi not uscd much tod^y Uscs: diagnostic casts, opposing arch casts, and removable prosthodontics . Also called: "Ycllow Stone", or "Microslonc" Ttpe IY Glpsum: Dic stonc. Low Expans;on" . Conprcssion srcngth: 5000 psi . . . Pcrccntagc ofexpansioni 0.10% Lscs: dics for crown, bridg€, and implants {1so callcd: Dcnsitc or lmprovcd Dcntal Stonc" Ttpe \. Gtprum: Dic Slonc, Hjgh Expansion" . f..mpressron strcngth; 7000 psi . P.rc.nlagc ofexpansion: 0.10% . LiJs: di.s for crown and bridgc . \1io callcd: "DieKccn"

If your patient indicates a tendency to gag while taking alginate impressions, all of the following maneuvers can help EXCEPT one. Lessening the time to take an impression Using cold water to mix the alginate Having the patient breathe through his / her nose Seating the patient in an upright position Seating the posterior portion of the tray first

Using cold water to mix the alginate Cold water will make the alginate take longer to set. Mixing the alginate material rapidly will cause setting to occur more rapidly. Decreasing the water to powder ratio will cause alginate to set up more rapidly consistenc.,^ of the mit -mix is much thicker v'hen less v'ater is used). Note: The mandibular alginate impression is taken first since gagging is more likely to occur when taking the ma"xillary impression. For the maxillary impression, the posterior portion of the tray is seated first, then the anterior portion. This helps to prevent the alginate material from being squeezed out of the tray, back torvard the patient's throat hrhich may cause gagging). Alrvays remove alginate impressions in one quick movement, with a snap. This helps to decrease permanent deformation. l. The setting reaction of alginate is a "double decomposition" .\-ores tween potassiurn alginate and calcium sulfate. Also remember that casts must . , - -,,,. be poued within 24 hours and the impression must be kept damp. 2. Both under and over-mixing can reduce the strength ofthe impression- 3. Do not over-seat the tray - (affects reaction be- 0.25 inch (minimum) of alginate should remain over all critical strucl]tj'es (especially occlusal surfaces).

Endo treated teeth that have been restored with a cast post and core and cron are subjected to a high incidence of Periodontal disease Recunent caries Vertical root fracture The need for an apicoectomy

Vertical root fracture The main symptom will almost always be pain when biting. The radiograph usu- ally appears normal. Advantages of using a post and core as opposed to a post crown when restoring en- dodontically treated teeth: . . The marginal adaption and fit ofthe restoration is independent on the fit ofthe post The restoration can be replaced at some time in the future, ifnecessary without disturbing the post and core . Ifthe endodontically treated tooth is to serve as a bridge abutment, it is not necessary to make the root canal preparation parallel with the line of draw ofother preparations - it can be treated as an independent abutment The post and core, when used, is made separate from the final restoration. The crown is then fabricated and cemented over the core preparation done in tooth structure. just as a restoration would be placed over a For teeth with little or no clinical crown that have roots with adequate length, bulk, and straightness, a post and core can be utilized. For posterior teeth with less extensive de- struction ofcoronal tooth structure, or for those possessing less favorable root conhgurations. a pin retained amalgam or composite core can be used.

When using the impression mterial can you delay pouring up of the model for up to one week Polyether Polysulfide Reversible hydrocolloid Vinyl polysiloxane

Vinyl polysiloxane (aka addition silicones) Polyvinyl sifoxanes (addition silicohes.) are the most widely used and are the most accurate of the elastic impression materials. They have less polymerization shrinkage, low distortion, fast recovery from deformation and a moderately high tear strenglh. Most ofthe pol;vinyl siloxanes can be pourcd up to one week after impression making and are stable in most sterilizing solutions. Important; Tle sulfur in latcx glovcs and in ferric and aluminum sulfate retraction solution will retard the setting ofaddition silicone materials. Also, addition silicones are temperature sensitive shorten the working and sefting times. Composition of polyvinyl siloxanes . . . . Base: silicone polymer Catalyst: chloroplatinic acid Filler: colloidal silica Scavengers: platinum or palladium /addition /acr si[icones): as scavengers for -increases in temperature will the hydrogen gas releosed) 1. The addition reaction that occurs with pol''vinyl siloxanes is terminated with a vinyl group \otes, and crosslinked with hydride groups activated by a platinum salt catalyst No reaction by- products are developed, but hydrogen gas release may occur ifa reaction betwem moisture and rcsidual hydrides ofthe base polymer occurs. The result is a cast with small voids ifthe impression is poured too soon after removal from the mouth. 2- Stiffness ofthc matcrial makes removal ofthe trav difficult.

All of the following are indications for electrosurgery EXCEPT To remove hyperplastic gingival tissue where it has proliferated into preparations or over crown margins In place of gingival retraction cord where substantial attached gingiva is present Where attached gingival tissues are thin, or where an underlying dehiscence is suspected For crown-lengthening procedures prior to fabricating a provisional crown

Where attached gingival tissues are thin, or where an underlying dehiscence is suspected This is a contradiction to electrosurgery this p.ocedure. Objectives of electrosurgery: . . . Coagulation Hemostasis Access to cavosurface margin .Reduction sue) -gingival -shoulder r€cession may be marked following the use of ofthe inner wall ofthe gingival sjulcts (removal ofa thin layer ofcrevicular gingiwl tis- Electrosurgery, although considered by many to be a more radical means ofrefiaction ofgingival tis- sues. is an acceptable method. It functions by passing small curents ofelectricity through the gingival rissue, causing the cells to desiccate, or scorch. Electrosurgery usually results in sorne delayed healing because ofthe lack of proper clot formation. It is very good at stopping hemorrhage. Note: Too low a current in an electrosurgical electrode can be detected by tissue drag. Important points about elechosurgery: . Use pfastic instruments (nirror explorer, erc) instead of metal to prevent buming and tissue de- struction of the surface contacted. . . . Rapid, single, light strokes should be used with the electrode 5 secotrd intervlls should be used when cutting The electrode should not contact metallic restorations or tooth skucture (may cause ineversible pulp damage). Great care must be employed when performing electrosurgery as the potential exists for serious damage to the PDL and surrounding bone, resulting in loss ofattachment ofthe tooth. Note: elechosurgery is not recommended for thin attached gingiva. Important: Electrosurgery is contrai[dicated in patients using medical devices such as cardiac pace- make$, a trancutaneous electrical nerve stimulation (TENS) :urit, or an insulin pump, and in patients with delayed healing.

The posterior paltl seal for a maxillary denture Is placed 3 mm posterior to the vibrating line Is not necessary when fabricating a complete denture on a patient with a flat palate Is not necessary if a metal base is used Will vary in outline and depth according to the palatal form ofthe patient

Will vary in outline and depth according to the palatal form ofthe patient The posterior palatal se|l is completed before the final arangement ofthe posterior teeth because this firal patient. The anterior lilre that indi_ cates the location ofthe poste or arrangement is a laboratory procedure and is done in the absence of the palatal sealis drawn on the cast in fiont ofthe line indicating the end ofthe denture. The width ofthe posteriorpalatal sealitselfis limited to a bead on the denture that is I to 1.5 mm high and 1.5 mm broad rt its base. A greater width creates an area oftissue placement that will have a tendency ro push the denture downward gradually and to defeat the purpose ofthe posterior palatal seal ln other words, rhe posterior palatal seal should not be made too wide. A !'-sh|ped grcove I to 1.5 mm deep is carved into the cast at the location ofthe bead. A large, sharp scmper is used to carve it, passing through the hrmuler notches and across the palate ofthe cast. The groove will form a head on the denture that prcvides the posterior palatal seal. The b€ad will be I to 1.5 mm high, 1.5 mm wide at its base, and sh|rp tt its apex. The depth ofthe grooves will be determined by the thickness ofthe soft tissue against which it is placed and will establish $e height of the bead

In metal ceramic restorations failure or frcture usually occurs ln the porcelain At the porcelain-metal interface In the metal

ln the porcelain One of the major reasons for the acceptance ofporcelain fused to metal restorations is its greater strength and resistance to fracture. The combination of porcelain and metal, fused together, is stronger than porcelain alone. Because true adhesion occurs, the bond strength is such that failure or fracture will occur in the porcelain farther than at the porcelain-metal interface. Important points conceming the metal-ceramic crown: . The necessary thickness ofthe metal substructue is 0.5 mm . . The minimal porcelain thickness is 1.0-1.5 mm Based on the above points, the tooth reduction necessary for the metal-ceramtc crown is approximately 1.5-2.0 mm. The labial shoulder width is ideally 1.5 mm. . The most frequent cause ofporosity in the porcelain is inadequate condensation of the porcelain . The effectiveness ofcondensing porcelain powder to reduce shrinkage is determined by the shape and size ofthe particle Rememb€r: Porcelain is much stronger under compressive forces than it is when subjected to tensile forces by the opposing teeth. Porcelain fracture in all-ceratnic restorations can be avoided by keeping the angles ofthe pr€paration rounded.

A patient who wears a complete msxillary denture complains of a burning sensation in the palatal area of his/her mouth. This is Indicative of too much pressure bcing exerted by the denture on the: Facial to the ridge Lingual to the ridge Exactly over the ridge lncisive foramen Palatal mucosa Hamular notch Posterior palatal seal

lncisive foramen 1. A burning sensation in the mandibular anterior area is caused by pressure on the mental foramen. 2. A patient having trouble swallowing may have insufficient interocclusal space clusion. -decreased freeway space caused by excessive vertical dirrension oloc- 3. The best dietary advice for an elderly denture patient is to eat foods rich in protein and vitamins A, C, D, and B complex. Important: Leaming to chew satisfactorily with new dentures requires at least 6-8 weeks. This time is spent on establishing new memory patterns for both facial and masticatory muscles. Residual ridges can be ruined by the use of denture adhesives and home-reliners. Therefore. patients should be specifically warned about their uses. These agents can mod- ifl the position ofthe denture on the ridge and result in change ofboth vertical and cen- tric relations.