Periodontic2/2 oral hygene

Because of the high turnover rate, the connective tissue of the gingiva has a remarkably good healing and regenerative capacity. The reparative capacity of the gingival connective tissues is not as great as that of the periodontal ligament or the epithelial tissue. • both statements are true • both statements are false • the first statement is true, the second is false • the first statement is false, the second is true 由于周转率高，牙龈的结缔组织有一个 恢复能力非常好。 牙龈结缔组织的修复能力不如 牙周膜或上皮组织。 •两个声明都是真实的 •两个语句都是假的 •第一个陈述是真实的，第二个是假的 •第一个陈述是假的，第二个是真的

both statements are true The dominant cellular element in the gingival connective tissue is the fibroblast. Numerous fibroblasts are found between the fiber bundles. Fibroblasts are of mesenchymal origin and play a major role in the development, maintenance, and repair of gingival connective tissue. Mast cells are numerous in the connective tissue of the oral mucosa and the gingiva. Fixed macrophages and histiocytes are present in the gingival connective tissue as components of the mononuclear phagocyte system and are derived from blood monocytes. Adipose cells and eosinophils, although scarce, also are present in the lamina propria. In clinically normal gingiva, small foci of plasma cells and lymphocytes are found in the connective tissue near the base of the sulcus. These inflammatory cells usually are present in small amounts in clinically normal gingiva. Three sources of blood supply to the gingivaare as follows: 1. Supraperiosteal arterioles: along the"facial and lingual surfaces of the alveolar bone, from which capillaries extend along the sulcular epithelium and between the rete pegs of the external gingival surface. 2. Vessels of the PDL:which extend into the gingiva and anastomose with capillaries in the sulcus area. 3. Arterioles: which emerge from the crest of the interdental septa and extend parallel to the crest of the bone to anastomose with vessels of the PDL. The lymphatic drainage of the gingiva brings in the lymphatics of the connective tissue papillae. It progresses into the collecting network external to the periosteum of the alveolar process, then to the regional lymph nodes, particularly the submaxillary group. Within the gingival connective tissues, most nerve fibers are myelinated and are closely associated with the blood vessels. Gingival innervation is derived from fibers arising from nerves in the PDL and from the labial, buccal, and palatal nerves.

It is impossible to carry o ut peridontal procedures efficiently w i th dull instru-ments. A sharp instrument cuts more precisely and quickly than a dull instrument. • both statements are true • both statements are false • the first statement is true, the second is false • the first statement is false, the second is true 不可能有效地进行肛门手术的手术。 锋利的仪器比平淡的仪器更精确和快速地切割。 •两个声明都是真实的 •两个语句都是假的 •第一个陈述是真实的，第二个是假的 •第一个陈述是假的，第二个是真的

both statements are true To do its j ob at all, a dull instrument must be held more firmly and pressed harder than a sharp instru-ment. This reduces tactile sensitivity and increases the possibility that the instrument will inadvertently slip. The objective of sharpening is to restore the fine, thin, linear cutting edge of the instrument. This is done by grinding the surfaces of the blade until their junction is once again sharply angular rather than rounded. It is important to restore the cutting edge without distorting the original angles of the instrument. When these angles have been altered, the instrument does not function as it was designed to function, which limits its effectiveness. Principles of sharpening: • Choose sharpening stone appropriate for instrument (flat, cone, coarse, etc.) • Use a sterilized sharpening stone if the instrument to be sharpened will not be resterilized before it is used on a patient . • Establish the proper angle between the stone and the surface of the instrument • Maintain a stable, firm grasp of both the instrument and the sharpening stone • Avoid excessive pressure • Avoid formation of a "wire edge," which is produced when the direction of the sharpening stroke is away from, rather tharTinto or toward, the cutting edge. When back-and-forth or up-and-down sharpemng strokes are used, formation of a wire edge can be avoided by finishing with a down stroke toward the cutting edge. • Lubricate the stone during sharpening. Oil should be used for natural stones and water for synthetic stones • Sharpen instruments at first sign of dullness Note: The technique for sharpening a universal curette can be used to sharpen a Gracey curette. How-ever, bear in mind that the Gracey's cutting edge is offset and it also curves, unlike the universal's cut-ting edge. Remember: India and Arkansas oilstones are examples of natural abrasive stones. Carborundum, ruby, and ceramic stones are synthetically produced

The most accepted theory as to the cause of root sensitivity is the: • bayer's theory 1 chemiosmotic theory • hydrodynamic theory •quantum theory 关于根敏感原因的最接受的理论是： 拜耳的理论 1化学溶解理论 •流体力学理论 •量子理论

hydrodynamic theory The Hydrodynamic theory postulates that the pain of root sensitivity results from indirect innervation caused by dentinal fluid movement in the tubules, which stimulates mechanoreceptors in the pulp. Root hypersensitivity is a relatively common problem in periodontal practice. It may occur spontaneously when the root becomes exposed as a result of gingival recession or pocket formation, or it may appear after scaling and root planing and surgical procedures. The primary symptom is cold sensitivity. Plaque and food debris, if allowed to remain on exposed root surfaces, often lead to increased sensitivity. Note: To reduce the sensitivity to thermal change after removal of a periodontal dressing, it is best to keep the roots free of plaque. The most common agents used by the patient for oral hygiene are dentifrices. Although many dentifrice products contain fluoride, additional active ingredients for desensitization are strontium chloride, potassium nitrate, and sodium citrate. The ADA has approved the following dentifrices for desensitizing purposes: Se«sodyne and ThermoDent, which contain strontium chloride; Qgst Sensitivity Protection, Denquel, and Promise, which contain potassium nitrate; and Protect, wfcrhcontams sodium citrate. Important: Desensitizing agents act through the precipitation of crystalline salts on the dentin surface, which block dentinal tubules. Various office treatments for the desensitization of hypersensitive dentin: • Cavity varnishes • Antiinflammatory agents • Treatments that partially obturate dentinal tubules - Burnishing of dentin - Silver nitrate - Zinc chloride-potassium ferrocyanide - Formalin - Calcium compounds: • Calcium hydroxide • Dibasic calcium phosphate - Fluoride compounds • Sodium fluoride • Stannous fluoride - Iontophoresis - Strontium chloride - Potassium oxalate - Restorative agents - Dentin bonding agents

A curette designed to scale and root plane anterior teeth will have a: • short, straight shank • long, straight shank • short, angled shank • long, angled shank 设计用于鳞片和根平面前方的刮刀将具有： •短直柄 •长而直的柄 •短，有角度的柄 •长而有角度的柄

long, straight shank How an instrument shank is designed influences the intended use of the instrument. It is rec-ommended that an instrument with a rigid shank be used for removal of heavy calculus de-posits. *** Straight shames are used in the anterior areas and contra:angled shanks a r e j a ^m the posterior areas. Rigid, thick shank: • Stronger • Less flexible • Provides less tactile sensitivity • Stronger instruments are needed for heavy calculus removal Less rigid, more flexible shank: • Provides more tactile sensitivity • Used for removing fine calculus and for root planing Important: The Gracey curettes differ from the universal curettes in that the blade is not at a 90-degree angle to the lower shank. The term offset blade is used to describe Gracey curettes, because they are angled approximately 60 to 70 degrees from the lower shank. ^/ ^ttgulatinn}efers to the angle between the face of the bladed instrument and the tooth sur-face°ltJtnayalso be called the tooth-blade relationship. During scaling and root planing, op-timal angulation is between 45: and 90 degrees. With angulation of less than 45 degrees, the cutting edge will not bite into or engage the calculus properly. Instead, it will slide over the calculus, smoothing or "burnishing" it. If angulation is more than 90 degrees, the lateral sur-face of the blade, rather than the cutting edge, will be against the tooth, and the calculus will not be removed and may become burnished. Q^ Note: When gingival curettage is indicated, angulation greater than 90 degrees is deliberately established so that the cutting edge will engage and remove the pocket lining.

If a patient experiences sensitivity w h i le being scaled with an ultrasonic scaling device, all of the following actions will be appropriate to counter this problem EXCEPT two. W h i ch t wo a re i n a p p r o p r i a t e? • proceeding to another tooth and then returning to the sensitive tooth later in the appointment • moving the instrument slower • making necessary adjustments to the water spray • t u r n i ng up the power of t he device • using less pressure 如果患者经历了敏感度，那么它将被缩放 使用超声波缩放设备，除了两个以外，以下所有操作都将适用于此。 我想要做一个工作？ •前往另一颗牙齿，然后在任用期间返回敏感牙齿 •移动仪器较慢 •对喷水进行必要的调整 •提高设备的电源 •使用较少的压力

moving the instrument slower • t u r n i ng up the power of t he device *** The opposite of these is true!! All of the rest are appropriate actions to be considered in that situation. If sensitivity is encountered during use: • Lighten the pressure • Adjust the water spray: increase water flow to cool the tip • Move to another tooth and then return later to the sensitive tooth •Decrease the power Power-driven instruments work best with quick hand movement ~ rapid, controlled movements. Remember: *** The ultrasonic principle is based on the use of high-frequency sound waves.

Which of the following is the only local delivery system of antibiotics acccepted by the ADA and is available in the United States and a number of other countries? • 10%doxycyclinegel - * fo&\c&a& • 2% minocycline microspheres —£ fi^^es-tj ^» • 25% metronidazole gel • chlorhexidine (2.5mg) in gelatin matrix —^ f U\ i©CkvLf . 以下哪一个是抗生素唯一的本地递送系统 被ADA接受，并在美国和其他一些国家可以使用？ •10％多西环素 - * fo＆\ c＆a＆ •2％米诺环素微球 - •25％甲硝唑凝胶 •明胶基质中的洗必太（2.5mg） - ^©CkvLf。

nt*1 \ct&0 / T ^ 10% doxycycline gel The limitations of mouth rinsing and irrigation have prompted research for the development of alternative delivery systems. Recently, advances in delivery technology have resulted in the controlled release of drugs. • Subgingival Doxycycline: the FDA approved 10% doxycycline in a gel system using a syringe (ATRICDOX. It is the only local delivery system accepted by the ADA. • Subgingival Minocycline: the FDA recently approved a new, locally delivered, sustained-release form of minocycline microspheres (ARESTIN) for subgingival placement as an adjunct to scaling and root planing. The 2% minocycline is encapsulated into bioresorbable microspheres in a gel carrier. • Subgingival Metronidazole: a topical medication containing an oil-based metronidazole 25% dental gel (glycerol monooleate and sesame oil) has been tested in a number of studies. This product is hot available in the U.S. • Chlorhexidine in a gelatin matrix: a resorbable delivery system has been tested for the subgingival placement of chlorhexidine gluconate with positive clinical results. PerioChip is a small chip (4.0 x 5.0 x 0.35 mm) composed of a biodegradable hydrolyzed gelatin matrix, cross-linked with glutaraldehyde and also containing glycerin and water, into which 2.5 mg of chlorhexidine gluconate has been incorporated per chip. Systemic administration of antibiotics: • Tetracyclines: used to treat LAP (locally aggressive periodontitis): have the ability to concentrate in the periodontal tissues and inhibit the growth of Actinobacillus actinomycetemcomitans (Aa). Note: Subantimicrobial- dose doxycycline (SDD) is a 20-mg dose of doxycycline (Periostat) that is approved and indicated as an adjunct to scaling and root planing in the treatment of chronic periodontitis. It is taken twice daily for 3 months, up to a maximum of 9 months continuous dosing. • Metronidazole: is effective againstAa when used in combination with other agents. It is effective against anearobes such as Pprphyromonas gingivalis and Pyevotella intermedia. • Penicillins (amoxicillin and amoxicillin-clavulanatepotassium [Augmentin]): may be useful in the managment of aggressive periodontitis (both localized and generalized forms). • Cephalosporins: not often used to treat dental-related infections. • Clindamycin: used when patients are allergic to penicillin. .' • Ciprofloxacin: is the only antibiotic in periodontal therapy to which all strains of Aa are susceptible. • Macrolides (erythromycin, spiramycin, and azithromycin): only azithromycin is used and appears to concentrate in gingival tissues.

Which of the following oral hygiene aids is appropriate for cleaning a Class IIfurcation? • stim-u-dent® • interproximal brushes • interdental stimulator • perio-aid® • oral irrigator 以下哪种口腔卫生用具是否适合清洁II级脓肿？ •刺激u •邻近刷子 •齿间刺激器 •perio-aid® •口腔冲洗器

perio-aid A tapered, round toothpick is inserted into the hole in the carrier and is then broken off. The tip is left in and is used in a tracing motion along the gingival margins. It is also helpful in cleaning furcations that are accessible. • Stim-U-Dent® (balsa wood wedges): these are of primary importance in gingiva] igassage. They are also good for patients with interdental recession. These picks (triangular in cross section) are small enough to fit into most interdental spaces. As a supplement to brushing, they are useful for dislodging interproximal debris often missed by meticulous brushing and for massaging the underlying interproximal gingiva. • Interproximal brushes (Proxabrush): are used for interdental cleansing when the interdental space is wide. The brushes are replaceable. • Interdental stimulator: consists of a rubber tip of smooth or ribbed conical shape attached to a handle or to the end of a toothbrush. Its action massages and stimulates circulation of the interdental gingiva and may increase the tone of the tissue. It is not recommended for areas in which the papillae are normal and fill the interproximal spaces. It may cause injury to the gingival tissue. Remember: 1. Nothing replaces brushing and flossing for removal of or disruption of plaque. 2. Frequent brushing and flossing helps to prevent calculus formation by breaking up the matrix of plaque. 3. New plaque growth occurs shortly after brushing and flossing (starts interproximal and works its way around the tooth).

Which component of Super Floss" is most effective in cleaning around appliances and between wide spaces? • stiffened end •spongy floss • regular floss Super Floss的哪个组件"在家电清洁和广泛空间之间最有效？ •加固端 •海绵线 •常规牙线 103

spongy floss Super Floss® is ideal for cleaning braces, bridges, and wide gaps between teeth. Its three unique components - a stiffened end, spongy floss, and regular floss - all work together for maximum benefits. Three components: • Stiff-end threader so you can floss under appliances • Spongy floss cleans around appliances and between wide spaces • Regular floss removes interproximal subgingival plaque Indications for use of Super Floss® include plaque removal around the following: - Isolated teeth - Teeth separated by a diastema - Wide embrasures where interdental papillae have been lost - Fixed partial dentures (bridgework) - Orthodontic appliances - Implants

The sulcular epithelium is a: • thick, keratinized stratified squamous epithelium without rete pegs • thick, nonkeratinized stratified squamous epithelium with rete pegs • thin, keratinized nonstratified squamous epithelium with rete pegs • thin, nonkeratinized stratified squamous epithelium without rete pegs 该龈沟上皮是： •厚厚的角质化分层鳞状上皮，无复发 •厚，非角质化分层鳞状上皮细胞 •薄，角质化的非分层鳞状上皮细胞 •薄，非角质化的分层鳞状上皮，无复发

thin, nonkeratinized stratified squamous epithelium without rete pegs The epithelial component of the gingiva shows regional morphologic variations that reflect tissue adaptation to the tooth and alveolar bone. These variations include: • Oral (outer) epithelium: covers the crest and outer surface of the marginal gingiva and the surface of the attached gingiva. On average, the oral epithelium is 0.2 to 0.3 mm in thickness. It is keratinized or parakeratinized. The oral epithelium is composed of four layers: stratum basale. stratum spinosum, stratum granulosum, and stratum.cprneum. • Sulcular epithelium: lines the gingival sulcus; it is a thin, nonkeratinized stratified squamous epithelium without rete pegs, and it extends from the coronal limit of the junctional epithelium to the crest of the gingival margin. • Junctional epithelium: consists of a collarlike band of stratified squamous jtonksratinizing epithelium. It is three to four layers thick in early life, but the number of layers increases with age to 10 or even 20 layers. Also, the junctional epithelium tapers from its coronal end, which may be 10 to 29 cells wide to one or two cells at its apical termination, located at the CEJ in healthy tissue. These cells can be grouped in two strata; the basal layer facing the connective tissue and the suprabasal layer extending to the tooth surface. The length of the junctional epithelium ranges from fL21.fo..l..3.5 mm. Important: The attachment of the junctional epithelium to the tooth is reinforced by the gingival fibers, which brace the marginal gingiva against the tooth surface. For this reason, the junctional epithelium and the gingival fibers are considered a functional unit, referred to as the dentogingival unit. Note: Histologically, the best way to distinguish the free gingiva from the epithelial attachment is the fact that the epithelium of the epithelial attachment does not contain rete pegs and the free gingiva does. Rete pegs are epithelial projections that extend into the gingival connective tissue. Connective tissue projections that extend into the overlying epithelium are called connective tissue papillae.

The most important factor in the control of hypersensitive roots among patients with periodontal disease after gingival recession has exposed the cervical portions of teeth is: • prescription of home fluoride rinses • minimal removal of tooth structure during root planing • the application of desensitizing agents that contain fluoride • thorough daily plaque control 143 控制患者过敏根的最重要因素 牙龈退缩后牙周病已暴露宫颈 部分牙齿是： •处方氟化物漂洗 •根刨期间牙齿结构最小化 •应用含氟化物的脱敏剂 •彻底的每日斑块控制 143

thorough daily plaque contro Sometimes these areas will become sensitive if the root is exposed. The patient will complain of cold sensitivity. The hypersensitivity will sometimes subside in time with daily plaque removal using a soft brush (this will help desensitize the root surface by allowing remineralization of the root surface). Remember: Gingival recession can also occur secondary to periodontal therapy. This may have additional significance in the older patient, namely, increased risk for cervical abrasion and dentinal sensitivity, and most importantly, predisposition to root caries. The acids and toxins produced by the plaque organisms are very irritating to the pulp by way of the odontoblastic processes. This irritation of the pulp heightens its sensitivity to other stimuli. No attempt to reduce hypersensitivity will be successful unless the roots are consistently kept free of plaque. Desensitizing agents can be applied by the patient at home or by the dentist or hygienist in the dental office. The most likely mechanism of action is the reduction in the diameter of the dentinal tubules so as to limit the displacement of fluid in them. This can be attained by: • formation of a smear layer produced by burnishing the exposed surface • topical application of agents that form insoluble precipitates within the tubules • impregnation of tubules with plastic resins • sealing of the tubules with plastic resins The hygienist or dentist should evaluate the brushing technique and monitor hard and soft tissue conditions at each recall visit. Faulty placement, overaggressive movement or pressure, or the use of a hard toothbrush can lead to hard and soft tissue damage. The most common cause of gingival recession is tooth injury (abrasion). This type of recession is common on the left canines of right-handed persons (or right canines of left-handed persons).

While scaling subgingivally, the tip of the curette breaks off. All of the fol-lowing a re a p p r o p r i a te actions to t a ke to t ry a nd r e m o ve t h is t ip EXCEPT o n e. Which o ne is t he EXCEPTION! • use a push stroke to force the tip out of the sulcus • gently examine the gingival sulcus • take a periapical radiograph of the area place the patient in an upright position 在龈下伸展时，刮匙的尖端会脱落。 以下所有的操作都可以通过以下方式实现：除了EXCEPT之外。 哪个是他的例外！ •使用推动行程将尖端推出沟槽 •轻轻检查牙龈沟 •拍摄该地区的胸膜前摄影 将患者置于直立位置

use a push stroke to force the t ip out of t he sulcus *** Never use a push stroke, this could force the tip further into the sulcus. Gently examine the sulcus using a curette in a spoon-like stroke, attempting to pull the fragment out. The procedure should be stopped immediately and the patient placed in an upright position. Be-fore proceeding subgingivally, check the floor of the mouth and the mucobuccal fold for the frag-ment. A p e r i a p i c al radiograph should then be taken before going any further to locate the fragment. Try not to alarm the patient. The last thing you want is for the patient to become frantic. The best way to prevent curette breakage is to use proper sharpening techniques to maintain the original instrument design and to discard instruments when the blade starts to thin out. A thinner blade is weaker and will break more easily. Remember: The Schwartz PeriotrieverS;are highly magnetized instruments designed for the re-trieval of broken instrument tips from the periodontal pocket. \x^ Comparison of Area-Specific (Gracey) and Universal Curettes Area of use Cutting Edge Use Curvature Blade angle Gracey Curette Set of many curettes, designed for specific areas and surfaces Universal Curette One curette designed for all areas and surfaces One cutting edge used; work with outeredge only Curved in two planes; blade curves uEandiaJJSJMe Offset blade; face of b l a de beveled at 60 degrees to shank Both cutting edges used; work with either outer or inner edge Curved in one plane; blade curves up, not to the side Blade not offset; face of b l a de beveled at 90 degrees to shank

In magnetostrictive ultrasonic units the pattern of vibration of the tip is linear. In piezoelectric ultrasonic units the pattern of vibration of the tip is elliptical. • both statements are true • both statements are false • the first statement is true, the second is false • the first statement is false, the second is true 在磁致伸缩超声单元中，尖端的振动模式是线性的。 在压电超声单元中，尖端的振动模式是椭圆形的。 •两个声明都是真实的 •两个语句都是假的 •第一个陈述是真实的，第二个是假的 •第一个陈述是假的，第二个是真的

• both statements are false The two types of ultrasonic units are magnetostrictive and piezoelectric. In both types, alternating elec-trical current generates oscillations in materials in the handpiece that cause the scaler tip to vibrate. De-pending on the manufacturer, these ultrasonic vibrations at the tip of the instruments of both types range from 20,000 to 45,000 cycles per second. In magnetostrictive units, the pattern of vibration of the tip is elliptical, which means that all sides of the tip are active and will work when adapted to the tooth. In piezoelectric units, the pattern of vibration of the tip is linear, or back and forth, meaning that the two sides of the tip are the most active. Sonic units consist of a handpiece that attaches to a compressed air line and uses a variety of specially designed t i p s. Vibrations at the sonic tip range from 2-flUO. to tiSOOrjTs which provides less power for cal-culus removal than ultrasonic units. Ultrasonic and sonic tips are designed to operate in a wet field with a water spray directed at the end of the tip. Within the water droplets of this spray mist are tiny vacuum bubbles that quickly collapse, re-leasing energy in a process known as cavitation. The cavitating water spray serves to flush calculus, plaque, and debris dislodged by the vibrating tip from the pocket. Mag&gtcjtjictiye ultrasonic tips gen-erate heat and require this water for cooling. Sonic and piezoelectric units do not generate this heat but still utilize water for cooling frictional heat and flushing away debris. Rental Endoscope: this device consists of a resusable fiberoptic endoscope over which is fitted a dis-posable sterile sheath. It fits onto periodontal probes and ultrasonic instruments that have been designed to accept it. This device allows clear visualization deeply into subgingival pockets and furcations. It per-mits operators to detect the presence and location of subgingival deposits. EVA system (enhanced visual assessment): this system uses motor-driven diamond files to correct over-hanging or overcontoured proximal alloy or resin restorations. Prophy-Jet air-powder polishing device: was the first specially designed handpiece to deliver an air-powered slurry of warm water and sodium.bic.arbonate for polishing. It is very effective for the removal of extrinsic stains and soft deposits. Note: Polishing powders containing aluminum trihydroxide or other substances rather than sodium bicarbonate are being used to offset the abrasive effect of sodium bicar-bonate on restorations as well as dentin and cementum. Contraindications to the use of air-powered pol-ishing devices are those patients with respiratory illnesses, hejnodialysis, hypertension, and infectious diseases.

Although the average width of the periodontal ligament space is documented to be about , considerable variation exists. • 0.002 mm • 0.2 mm • 2.0 mm • 20 mm 虽然牙周韧带空间的平均宽度被记录在案 存在相当大的差异。 •0.002毫米 •0.2 mm •2.0 mm •20毫米

• 0.2 mm ***The periodontal space is diminished around teeth that are not in function and in unerupted teeth, but it is increased in teeth subjected to hyperfunction. The periodontal ligament is composed of a complex vascular and highly cellular connective tissue that surrounds the tooth root and connects it to the inner wall of the alveolar bone. It is continuous with the connective tissue of the gingiva and communicates with the marrow spaces through vascular channels in the bone. The PDL is abundantly supplied with sensory nerve fibers capable of transmitting tactile, pressure, and pain sensations by the trigeminal pathways. Nerve bundles pass into the PDL from the periapical area and through channels from the alveolar bone that follow the course of the blood vessels. The bundles divide into single myelinated fibers, which ultimately lose their myelin sheaths and end in one of four types of neural termination: 1. Free endings, which have a treelike configuration and carry pain sensation. 2. Ruffini-like mechanoreceptors, located primarily in the apical area. 3. Coiled Meissner corpuscles, also mechanoreceptors, found mainly in the midroot region. 4. Spindlelike pressure and vibration endings, which are surrounded by a fibrous capsule and located mainly in the apex. A J * Note: Orthodontic treatment is possible because the PDL continuously responds and changes as a result of the functional requirements imposed on it by externally applied forces.

Early or young plaque consists primarily of • filaments • cocci • rods • vibrios 127 早期或年轻的斑块主要由 •细丝 •cocci •杆 •弧菌

• COCCI Bacterial plaque is the primary etiologic factor for the initiation of periodontal disease. Plaque formation begins immediately after a tooth surface is cleaned. The rate of plaque formation is affected by diet, age, salivary flow, oral hygiene, tooth alignment, systemic disease, and host factors. Changes in the types of organisms occur within plaque as the plaque matures. • Days 1 to 2: young plaque consists primarily of cocci (i.e., Streptococcus mutans and sanguis) • Days 2 to 4: cocci still dominate but there are increasing numbers oifjJamgrtous forms and slender rods. Gradually the filamentous forms replace many of the cocci. • Days 4 to 7: filaments increase in numbers, and a more mixed flora begins to appear with rods, filamentous forms, and fusobacteria. • Days 7 to 14: vibrios and spirochetes appear, and the number of white blood cells increases. More gramnegative and anaerobic organisms" appear. The signs of inflammation are beginning to be observable in the gingiva. • Days 14 to 21: vibrios and spirochetes are prevalent in older plaque, along with filamentous forms. Gingivitis is evident clinically. As plaque ages: • The number of cocci decreases and the number of rods, fusiform, filaments, and spirochetes increases • The number of aerobic bacteria decreases and the number of anaerobic bacteria increases • The number of gram-positive organisms decreases and the number of gram-negative organisms increases Key point: As the biofilm (plaque) matures, there is a shift from a predominance of facultative, gram-positive bacteria to gram-negative, anaerobic bacteria. The transition from gram-positive to gram-negative microorganisms observed in the structural development of dental plaque is paralleled by a physiologic transition in the developing plaque. The early colonizers (e.g., Streptococci, Actinomyces species) use oxygen and lower the redox potential of the environment, which then favors the growth of anaerobic species. Gram-positive species use sugars as an energy source and saliva as a carbon source. The bacteria that predominate in mature plaque are anaerobic and asaccharolytic and use amino acids and small peptides as energy sources. 1. The organic constituents of plaque include polysaccharides (dextran), proteins (i.e., albumin), Notes glycoproteins (from saliva), and lipid material. 2. The inorganic components of plaque are predominantly calcium and phosphorus, with trace amounts of other minerals, including sodium, potassium, and fluoride. 3.The source of inorganic constituents of supragingival plaque is primarily saliva.

When extensive scaling and root planing must be performed, the best approach would be: • a series of appointments set up to scale and root plane a segment or quadrant of teeth at a time (thoroughly and completely) • gross debridement (sub-and supragingival) of the entire mouth, followed by a series of appointments for fine scaling and polishing • perform everything in a single appointment • none of the above 当必须进行大规模的扩张和根除计划时，最好的办法是： •一系列任命，按比例和根平面划分为一个段或象限 一次牙齿（彻底彻底） •整个口腔的全面清创（分泌和分泌），其次是一系列 的任命，用于精细定标和抛光 •在单次约会中执行所有操作 • 以上都不是

• a series of appointments set up to scale and root plane a segment or quadrant of teeth at a time (thoroughly and completely) 1. There is potential for abscess formation in a deep pocket when only a su- Notes perficial scaling is performed. 2. OHI may be more effective if a patient can see healing tissue in an area that has been completely debrided and compare it to tissue in an untreated area. 3. A patient who has had a gross debridement will see a marked visual improvement of the oral cavity and may not understand the importance and necessity of the deep scaling and root planing appointments. This may cause the patient to not follow through with the scheduled treatment, and the patient's periodontal condition will be allowed to deteriorate further. 4.Important: Clinical evaluation of the soft tissue response to scaling and root planing, including probing, should not be conducted earlier than 2 weeks postoperatively. Reepithelialization of the wounds created during instrumentation takes 1 to 2 weeks. Until then, gingival bleeding on probing can be expected, even when calculus has been completely removed because the_so_ft tissue wound is not epifheliaiized. T . l f any bleeding or swelling is noted in localized areas of the mouth during the reevaluation appointment, check for and remove any residual calculus deposits that might remain. 6. In root planing, ideally, the working stroke should begin at the apical edge of the junctional epithelium (the base of the pocket).

The gingival fibers are arranged in three groups. Which of the following is not one of those groups? • circular group •gingivodental group •apical group • transseptal group 牙龈纤维分为三组。 以下哪一个不是其中之一？ •圆形组 •gingivodental组 •顶端组 •房间隔组

• apical group The connective tissue of the marginal gingiva is densely collagenous, containing a prominent system of collagen fiber bundles called the gingival fibers. They consist of type I collagen. The gingival fibers have the following functions: 1. To brace the marginal gingiva firmly against the tooth. 2. To provide the rigidity necessary to withstand the forces of mastication without being deflected away from the tooth surface. 3. To unite the free marginal gingiva with the cementum of the root and the adjacent attached gingiva- The gingival fibers are arranged in three groups: • Gingivodental group: these fibers are those on the facial, lingual, and interproximal surfaces. They are embedded in the cementum just beneath the epithelium at the base of the gingival sulcus. • Circular group: these fibers course through the connective tissue of the marginal and interdental gingivae and encircle the tooth in ringlike fashion. They resist rotational forces. • Transseptal group: these fibers are located interproximally and form horizontal bundles that extend between the cementum of approximating teeth into which they are embedded. They lie in the area between the epithelium at the base of the gingival sulcus and the crest of the interdental bone. They are sometimes classified with the principal fibers of the PDL. 1. The attachment apparatus is a term used to describe these gingival fibers and the Notes epithelial attachment. 2. Some studies have also described two more gingival fiber groups: (1) a group of semicircular fibers and (2) a group of transgingival fibers 3. Tractional forces in the extracellular matrix produced by fibroblasts are believed to be the forces responsible for generating tension in the collagen. This keeps the teeth tightly bound to each other and to the alveolar bone.

The principal fibers of the peridontal ligament are composed mainly of collagen type III. The amount of collagen in a tissue can be determined by its glycine content. • both statements are true • both statements are false • the first statement is true, the second is false • the first statement is false, the second is true 围壁韧带的主要纤维主要由胶原蛋白组成 III型。 组织中胶原的量可以通过其甘氨酸含量来确定。 •两个声明都是真实的 •两个语句都是假的 •第一个陈述是真实的，第二个是假的 •第一个陈述是假的，第二个是真的

• both statements are false Collagen is synthesized by fibroblasts, chondroblasts, osteoblasts, odontoblasts, and other cells. The several types of collagen are all distinguishable by their chemical composition, distribution, function, and morphology. The principal fibers of the periodontal ligament are composed mainly of collagen type I, whereas reticular fibers are composed of collagen type III. Collagen type IV is found in the basal lamina. Collagen is a protein composed of different amino acids, the most important of which are glycine, pro fine, hydroxylysine, and hydroxyproline. The amount of collagen in a tisue can be determined by its hydroxyproline content. Collagen is responsible for maintenance of the framework and tone of tissue. 1. Less regularly arranged collagen fibers are found in the interstitial connective Notes tissue between the principal fiber groups; this tissue contains the blood vessels, lymphatics, and nerves. 2. Although the PDL does not contain mature elastin, two immature forms are found; oxytalan and eluanin. The so-called oxytalan fibers run parallel to the root surface in a vertical direction and bend to attach to the cementum in the cervical third of the root. They are thought to regulate vascular flow. 3. The principal fibers are remodelled by the PDL cells to adapt"to physiologic needs and in repsonse to different stimuli.

The principal differences between intrabony and suprabony pockets are the relationship of the soft tissue wall of the pocket to the alveolar bone, the pattern of bone destruction, and the direction of the transseptal fibers of the periodontal ligament. In intrabony pockets, the base of the pocket is apical to the crest of the alveolar bone, and the pocket wall lies between the tooth and the bone. • both statements are true • both statements are false • the first statement is true, the second is false • the first statement is false, the second is true 肋骨和上臂囊之间的主要区别是口袋的软组织壁与牙槽骨的关系，骨破坏的模式以及牙周韧带的经纤维的方向。 在骨内的口袋，所述口袋的所述碱是顶端至牙槽骨的顶部，并且袋壁位于牙齿和骨之间。 •两个声明都是真实的 •两个语句都是假的 •第一个陈述是真实的，第二个是假的 •第一个陈述是假的，第二个是真的

• both statements are true Distinguishing Features of Suprabony and Intrabony Periodontal Pockets Suprabony Pocket 1. Base of pocket is coronal to level of alveolar bone. 2. Pattern of destruction of underlying bone is horizontal. 3. Interproximally, transseptal fibers that are restored during progressive periodontal disease are arranged horizontally in the space between the base of pocket and alveolar bone. 4. On facial and lingual surfaces, periodontal ligament fibers beneath pocket follow their normal horizontal-oblique course between the tooth and bone. Intrabony pocket 1. Base of pocket is apical to crest of alveolar bone so that the bone is adjacent to soft tissue wall. 2. Pattern of bone destruction is vertical (angular) 3. Interproximally, transseptal fibers are oblique rather than horizontal. They extend from cementum beneath base of pocket along alveolar bone and over crest to cementum of adjacent tooth 4. On facial and lingual surfaces, periodontal ligament fibers follow angular pattern of adjacent bone. They extend from cementum beneath base of pocket along alveolar bone and over crest to join with outer periosteum. Reproduced with permission, from Newman MG, Takei HH, Klokkevold PR, Carranza FA. Carranza's Clinical Periodontology,10th ed. Elsevier, 2006. •

Drug-induced gingival enlargement consists of a pronounced hyperplasia of the connective tissue and epithelium. Drug-induced gingival enlargement may occur in mouths with little or no plaque and may be absent in mouths with abundant deposits. • both statements are true • both statements are false • the first statement is true, the second is false • the first statement is false, the second is true 药物诱导的牙龈增大包括结缔组织和上皮的显着增生。 药物引起的牙龈增大可能发生在口中很少或没有 斑块，并且可能不存在具有丰富沉积物的口中。 •两个声明都是真实的 •两个语句都是假的 •第一个陈述是真实的，第二个是假的 •第一个陈述是假的，第二个是真的

• both statements are true Gingival enlargement is a well-known consequence of the administration of some anticonvulsants, immunosuppressants, and calcium channel blockers. Clinical and microscopic features of the enlargements caused by the different drugs are similar. The growth starts as a painless, beadlike enlargement of the interdental papilla and extends to the facial and lingual gingival margins. As the condition progresses, the marginal and papillary enlargements unite; they may develop into a massive tissue fold covering a considerable portion of the crowns, and may interfere with occlusion. When uncomplicated by inflammation, the lesion is mulberry-shaped, firm, pale pink, and resilient, with a minutely lobulated surface and no tendency to bleed. The presence of the enlargement makes plaque control difficult, often resulting in a secondary inflammatory process that complicates the gingival overgrowth caused by the drug. Secondary inflammatory changes not only add to the size of the lesion caused by the drug, but also produce a red or bluish-red discoloration, obliterate the lobulated surface demarcations, and increase bleeding tendency. Anticonvulsants: the first drag-induced gingival enlargements reported were those produced by phenytoin (Dilantin). Other hydantoins known to induce gingival enlargement are ethotoin (Peganone) and mephenytoin (Mesantoin). Other anticonvulsants that have the same side effect are the succinimides (ethosuximide [Zarontin], methsuximide [Celontin], and valproic acid [Depakene]). Immunosuppressants: Cyclosporine is a potent immunosuppressive agent used to prevent organ transplant rejection and to neat several diseases of autoimmune origin. Cyclosporine-induced gingival enlargement is.more vascularized than phenytoin enlargement. Another immunosuppressive drug, tacrolimus, has been used effectively and results in much less gingival overgrowth. Calcium channel blockers are drugs developed for the treatment of cardiovascular conditions. These drugs are the dihydropyridine derivatives (amlodipine [Lotrel, tiorvasc],felodipine [Plendil], nicardipine [Carden], nifedipine [Adalat, Procardia]); the benzothiazine derivatives (diltiazem [Cardizem, Dilacor-XR, Tiazac]); and the phenylalkylamine derivatives (verapamil [Calan, Isoptin, Verelan, Covera-HS]).

The junctional epithelium consists of a collarlike band of stratified squamous nonkeratinizing epithelium. The reduced enamel epithelium is not essential for its formation. • both statements are true • both statements are false • the first statement is true, the second is false • the first statement is false, the second is true 连接上皮由分层鳞状的领带组成 非角化上皮细胞 减少的牙釉质上皮对其形成不是必需的。 •两个声明都是真实的 •两个语句都是假的 •第一个陈述是真实的，第二个是假的 •第一个陈述是假的，第二个是真的 113

• both statements are true The junctional epithelium consists of a collarlike band of stratified squamous nonkeratinizing epithelium. It is three to four layers thick in early life, but the number of layers increases with age to 10 or even 20 layers. Also, the junctional epithelium tapers from its coronal end, which may be 10 to 29 cells wide to one or two cells at its apical termination, located at the CEJ in healthy tissue. These cells can be grouped in two strata; the basal layer facmg trie connective tissue and the suprabasal layer extending to the tooth surface. Note: The length of the junctional epithelium ranges from 0.25 to 1.35 mm (average is 0.97 mm). The junctional epithelium is formed by the confluence of the oral epithelium and the reduced enamel epithelium during tooth eruption. However, the reduced enamel epithelium is not essential for its formation; in fact, the junctional epithelium is completely restored after pocket instrumentation or surgery, and it forms around an implant. The junctional epithelium is attached to the tooth surface (epithelial attachment) by means of an internal basal lamina. It is attached to the gingival connective tissue by an external basal lamina. The internal basal lamina consists of a lamina densa (adjacent to the enamel) and a lamina lucida to which hemidesmosomes are attached. Hemidesmosomes have a decisive role in the firm attachment of the cells to the internal basal lamina on the tooth surface^ «w For a new attachment to form after periodontal treatment, the following must occur: '|/\t 1. Complete removal of calculus, altered cementum, diseased junctional epithelium, antral pocket epithelium 2. Need undifferentiated mesenchymal cells Important: The junctional epithelium in disease (which is referred to as a long junctional epithelium) is different from the junctional epithelium in health. In disease, migration of the junctional epithelium occurs, along with degeneration in the connective tissue under the attachment; as the junctional epithelium proliferates along the root surface (gets longer), the coronal portion detaches. Barrier membranes, which are often used to treat bony defects, help to prevent this long junctional epithelium from forming.

Some degree of curettage is done unintentionally when scaling and root planing are performed; this is called inadvertent curettage. Curettage accomplishes the removal of the chronically inflamed granulation tissue that forms in the lateral wall of the periodontal pocket. • both statements are true • both statements are false • the first statement is true, the second is false • the first statement is false, the second is true 刮除时可以进行一定程度的刮除术 被执行 这就是所谓的无意性刮宫。 净化剂完成长期发炎造粒的去除 在牙周袋的侧壁中形成的组织。 •两个声明都是真实的 •两个语句都是假的 •第一个陈述是真实的，第二个是假的 •第一个陈述是假的，第二个是真的

• both statements are true The word curettage is used in periodontics to mean the scraping of the gingival wall of a periodontal pocket to separate diseased soft tissue. Scaling reters to the removal of deposits from the root surface, whereas planing means smoothing the root to remove infected and necrotic tooth substance. A differentiation has been made between gingival and subgingival curettage. •.Gingival curettage: consists of the removal of the inflamed soft tissue.lateral to the pocket wall ^Subgingival curettage: refers to the procedure that is performed apical to the epithelial attachment, severing the connective tissue attachment down to the osseous crest. Indications for curettage are very limited. It can be used after scaling and root planing for the following purposes: "**-<" 1. Curettage can be performed as part of new attachment attempts in moderately deep intrabony pockets located in accessible areas where a type of^efosed" surgery is deemed advisable. 2. Curettage can be done as a nondefinitive procedure to reduce inflammation before using other methods for pocket elimination or when more aggressive surgical techniques (e.g., flaps) are^entraindicated. 3. Curettage is also frequently performed on recall visits as a method of maintenance treatment for areas of recjorrent inflammation and pocket depth. Important: Curettage does not eliminate the causes of inflammation (i.e., bacterial plaque and deposits). Therefore, curettaKshouMalwuysbe preceded by scaling and root planing. Note: Gingival curettage always requires some type of local anesthesia The curette is selected so that the cutting edge will be against the tissue (e.g., Gracey #13-14 for distal surfaces, Gracey #11-12 for mesial surfaces). Curettage can also be performed with a 4R-4L Columbia Unjversal curette.

At least two-thirds of the inorganic component of calculus is crystalline in structure. Of the four main crystal forms, which one is more common in the mandibular anterior region? magnesium whitlockite brushite octcalcium phosphate • hydroxyapatite 结石中至少三分之二的无机成分是结晶的。 在四种主要的晶体形式中，哪一种在下颌前区更常见？ 镁白铁矿 磷酸氢钙 磷酸三钙 •羟基磷灰石

• brushite Supragingival calculus consists of inorganic (70%-90%) and organic components. The inorganic portion consists of 76% calcium phosphate, 3% calcium carbonate, and traces of magnesium phosphate, and other metals. The principal inorganic components are calcium (39%); phosphorus (19%); carbon dioxide (1.9%); magnesium (0.8%); and trace amounts of sodium, zinc, strontium, bromine, copper, manganese, tungsten, gold, aluminum, silicon, iron, and fluorine. At least two-thirds of the inorganic component is crystalline in structure. The four main crystal forms are as follows: • Hydroxyapatite (58%) • Magnesium whitlockite (21%) • Octacalcium phosphate (12%) • Brushite (9%>) Generally, two or more crystal forms are typically found in a sample of calculus. Hydroxyapatite and octacalcium phosphate are detected most frequently (in 97% to 100% of all supragingival calculi) and constitute the bulk of calculus. Bjrai&hjte is more common in the mandibular anterior region and magnesium whitlockite in the posterior areas. The organic component of supragingival calculus consists of a mixture of protein-polysaccharide complexes, desquamated epithelial cells, leukocytes, and various types of microorganisms. The composition of subgingival calculus is similar to that of supragingival calculus, with some differences. Subgingival calculus has the same hydroxyapatite content, more magnesium whitlockite, and less brushite.and octacalcium than supragmgival"calculus. The ratio of calcium to phosphorus is higher subgingivally, and the sodium content increases with the depth of periodontal pockets. Salivary proteins present in supragingival calculus are not found subgingivally. Note: Calculus (both supragingival and subgingival) located on interproximal surfaces can be seen on bite-wing radiographs as interproximal spurs.

Which of the following types of oral mucosa is not keratinized under normal conditions? • buccal mucosa • vermillion border of the lips • hard palate • gingiva 以下哪种口腔粘膜在正常情况下不会角质化？ •颊粘膜 •嘴唇的朱红色边界 •硬腭 •牙龈 116

• buccal mucosa The three functional types of oral mucosa are lining, masticatory, and specialized mucosa. These terms provide functional descriptions of the oral mucosa in specific locations. • Masticatory mucosa: covers the gingiva and hard palate. - Epithelium: it has a keratinized or parakeratinized stratified squamous epithelium. - Lamina propria: has two layers: a thick papillary layer of loose connective tissue and a deep reticular layer of dense connective tissue. • Lining mucosa: covers all of soft tissue of the oral cavity except the gingiva, hard_rjalate, and dorsal surface of the tongue. - Ejplthelium: Generally, the epithelium of the lining mucosa is nonkeratinized. Qalfae^vermillipn. border of the lip, however, it is keratinized. If subject to unusual frictional stress, the epithelium may become parakeratinized or keratinized. Other cells found in the epithelium of the lining mucosa are Langerhans cells, melanocytes, and Merkel cells. - Lamina propria: Under the epithelium of the lining mucosa, a loose connective tissue with thin collagen fibers forms a papillary lamina propria that carries blood vessels, lymphatic vessels, and nerves. - Submucosal Adistinct submucosa underlies the lining mucosa, except on the inferior of the tongue. The submucosa contains large bands of collagen and elastic fibers that bind the mucosa "trTtne underlying muscle. The submucosa also contains the larger nerves, blood vessels, and lymphatic vessels that supply the neurovascular networks of the lamina propria throughout the oral cavity. In the lips, tongue, and cheeks, the submucosa contains many minor slaivary glands. - Specialized mucosa: is restricted to the dorsal surface of the tongue, and is characterized by the presence of surface papillae of several types and by taste buds in the epithelium^ The epithelium is keratinized. Important: All oral mucosa, whether keratinized, nonkeratinized, or parakeratinized, is of the stratified squamous type of epithelium and the underlying central core of connective tissue. Although the epithelium is predominantly cellular in nature, the connective tissue is less cellular and composed primarily of collagen fibers and ground substance.

Toothbrush trauma (abrasion) usually occurs on: • centrals and laterals • canines and premolars • second and third molars • first and second molars 牙刷创伤（磨损）通常发生在： •中心和侧向 •犬和前磨牙 •第二和第三磨牙 •第一磨牙和第二磨牙

• canines and premola *** Toothbrush trauma (abrasion) usually occurs on teeth that are the most prominent in the dental arch. The maintenance of oral health is enhanced by the use of a soft-bristle toothbrush with a dentifrice of optimum abrasiveness and a dental floss. A hard-bristle toothbrush is capable of causing gingival recession and abrasion of enamel and/or cementum and should be avoided. The abrasive quality of dentifrices affects enamel, but abrasion is more of a concern for patients with exposed dentin because dentin is abraded 25 times faster and cemgjvtjjBi^^jjaesi,,fajs.l;gr than enamel. This can lead to root surface abrasion and root sensitivity Hard tissue damage from oral hygiene procedures is mainly due to abrasive dentifrices, whereas gingival lesions can be produced by the toothbrush alone..*, Trauma from toothbrushing may result in the following: • Recession of the marginal gingiva • Lacerations of the soft tissues including the attached gingiva and the alveolar mucosa • V-shaped notches in the cervical areas of teeth • Gingival clefts: narrow grooves that extend from the crest of the gingiva to the attached gingiva Note: The location of the above alterations is frequently inversely related to the rightor left-handedness of the patient. Remember: In gingival atrophy or recession, the tissue appears to be otherwise normal. The gingiva is thin, finely textured and pale pink in color with normal papillae. The gingival sulci are very shallow. Plaque is minimal.

Water irrigation devices (oralirrigators) have been shown to: • eliminate plaque • clean nonadherent bacteria and debris from the oral cavity more effectively than toothbrushes and mouth rinses • disinfect pockets for up to 12 hours • prevent calculus formation 水灌溉设备（口腔灌溉机）已被证明： •消除斑块 •从口腔清洁干净的非粘附细菌和碎屑 有效地比 牙刷和漱口水 •消毒口袋长达12小时 •防止结石形成

• clean nonadherent bacteria and debris from the oral cavity more effectively than toothbrushes and mouth rinses Oral irrigators for daily home use by patients work by directing a high-pressure, steady or pulsating stream of water through a nozzle to the tooth surfaces. Most often, a device with a built-in pump generates the pressure. Oral irrigators clean nonadherent bacteria and debris from the oral cavity more effectively than toothbrushes and mouth rinses. When used as adjuncts to toothbrushing, these devices can have a beneficial effect on periodontal health by reducing the accumulation of plaque and calculus and decreasing inflammation and pocket depth. Oral irrigation has been shown to disrupt and detoxify subgingival plaque and can be useful in delivering antimicrobial agents into periodontal pockets. Note: Daily supragingival irrigation with a dilute antiseptic, chlorhexidine, for 6 months resulted in significant reductions in bleeding and gingivitis compared with water irrigation and chlorhexidine rinse controls. Irrigation with water alone also reduced gingivitis significantly, but not as much as the dilute chlorhexidine. Important: Oral irrigators may be contraindicated in patients requiring antibiotic premedication prior to dental treatment since these devices have the potential for causing a bacteremia. The patient's physician should be consulted. Remember: The pathology associated with gingivitis is completely reversible with the removal of plaque and the resolution of the inflammation.

Nearly all human oral bacteria exhibit,_____cell-to-cell recognition of genetically distinct cell types. • adhesion • pleomorphism • coaggregation • organization 几乎所有的人类口腔细菌都显示出_____细胞对细胞的识别 遗传上不同的细胞类型。 •附着力 •多形性 •共同集中 •组织

• coaggregation The process of plaque formation can be divided into three major phases: 1. The formation of the pellicle on the tooth surface: all surfaces of the oral cavity are coated with a pellicle (the initial phase of plaque development). Within nanoseconds after vigorously polishing the teeth, a thin, saliva-derived layer called the acquired pellicle, covers the tooth surface. This pellicle conists of numerous components, including glycoproteins (mucins), prolinerich proteins, phosphoproteins (e.g., statherin), histidine-rich proteins, enzymes (e.g., 'atpha-amylase), and other molecules that can function as adhesion sites for bacteria (receptors). Note: The mechanisms involved in enamel pellicle formation include electrostatic, van der Waals, and hydrophobic forces. 2. Initial adhesion and attachment of bacteria: - Phase 1: Transport to the surface: involves the initial transport of the bacterium to the tooth surface. - Phase 2: Initial adhesion: results in an initial, reversible adhesion of the bacterium, mediated through van der Waals and electrostatic forces. - Phase 3: Attachment: after initial adhesion, a firm anchorage between bacterium and surface will be established. - Phase 4: Colonization of the surface and biofilm formation: read #3 below 3. Colonization and plaque maturation: When the firmly attached microorganisms start growing and the newly formed bacterial clusters remain attached, mjcrofipjonies or a biofilm can develop. From this stage forward, new mechanisms are involved because new intrabacterial connections may occur. At least 18 genera from the oral cavity have shown some form of coag- ., greagation (cell-to cell recognition, of genetically distinct partner cell types). Essentially all oral bacteria (but especially Fusobacterium nucleatum) possess surface rnplecules that foster some type of cell-to-cell interaction. This process occurs primarily through the highly specific stereochemical interaction of protein and carbohydrate molecules located on the bacterial cell surfaces, in addition to the less specific interactions resulting from hydrophobic, electrostatic, and van der Waals forces.

Abrasives: • compose 5% to 10% of dentifrices • compose 10% to 20% of dentrifrices • compose 20% to 40% of dentrifices • compose 50% to 65% of dentrifices 磨料： •组成5％至10％的洁牙剂 •组成10％至20％的洁齿剂 •组成20％至40％的牙粉 •组成50％至65％的牙齿

• compose 20% to 40% of dentifrices Dentifrices aid in cleaning and polishing tooth surfaces. They are used mostly in the form of pastes, although tooth powders and gels are also available. Dentifrices are made up of abrasives (e.g., silicon oxides, aluminum oxides, granular polyvinyl chlorides), water, humectants, soap or detergent, flavoring and sweetening agents, therapeutic agents (e.g., fluorides, pyrophosphates), coloring agents, and preservatives. Abrasives (compose 20%, to 40% of dentifrices) are insoluble inorganic salts that enhance the abrasive action of toothbrushing as much as 40 times. Tooth powders are much more abrasive than pastes and contain about 95% abrasive materials. The abrasive quality of dentifrices affects enamel only slightly and is a much greater concern for patients with exposed roots. Dentin is abraded 25 times faster and cementum 35 times faster than enamel, so root surfaces are easily worn away, leading to notching and root sensitivity. Note: Typically, more wear occurs on maxilary than mandibular teeth and on the left half than on the right half of the dental arch. Important: In dentifrices, fluoride ion must be available in the amount of iQflfltaJHK) parts per million (ppm) to achieve caries reduction effects. "Calculus control toothpastes," also referred to as "tartar control toothpastes," contain pyrophosphates and have been shown to reduce the deposition of new calculus on teeth. These ingredients interfere with crystal formation in calculus but do not affect the fluoride ion in the paste. Dentifrice with pyrophosphates has been shown to reduce the formation of new supragingival calculus by 30% or more. Pyrophosphate-containing toothpastes donoj affect subgingival calculus formation or gingival inflammation. The inhibitory effect reduces the deposition of new supragingival calculus but will not affect existing calculus deposits.

Which of the following is the instrument of choice for removing deep subgingival calculus, for root planing altered cementum, and, for removing the soft tissue lining the periodontal pocket? • curette • sickle scaler • hoe • file 以下哪项是清除深龈下的首选仪器 用于牙根切面修改牙骨质，并用于去除牙垢 软组织内衬牙周袋？ •刮匙 •镰刀 •锄头 •档案

• curette Each working end of a curette has a cutting edge on both sides of the blade and a rounded toe. The curette is finer than the sickle scalers and does not have any sharp points or corners other than the cutting edges of the blade. Therefore, curettes can be adapted and provide good access to deep pockets, with minimal soft tissue trauma. In cross section, the blade appears semicircular with a convex base. The lateral border of the convex base forms a cutting edge with the face of the smemicircular blade. There are cutting edges on both sides of the blade. There are two basic types of curettes: • Universal curettes: have cutting edges that may be inserted in most areas of the dentition by altering and adapting the finger rest, fulcrum, and hand position of the operator. The blade size and the angle and length of the shank may vary, but the face of the blade of every universal curette is at a 90- degree angle (perpendicular) to the lower shank when seen in cross section from the tip. The blade of the universal curette is curved in one direction from the head of the blade to the toe. • Area-Specific curettes: Gracey curettes are representative of the area-specific curettes, a set of several instruments designed and angled to adapt to specific anatomic areas of the dentition. The Gracey curettes also differ from the universal curettes in that the blade is not at a 90-degree angle to the lower shank. The term offset blade is used to describe Gracey curettes, because they are angled approximately 60 to 70 degrees from the lower shank. 1. Using curettes with short, even working strokes followed by longer ones is the most effect- Notes ive and efficient way of performing root planing. The correct cutting edge can be seen as a larger, outer curve. 2. Final root planing strokes are longer and lighter than scaling strokes. 3. Root planing strokes become lighter as the cementum becomes smoother. 4. Exploratory scaling and root planing strokes differ in angulation, pressure, length, and direction. Remember: To establish the correct working angle once a curette is inserted subgingivally, the shank must be moved away from the tooth to open the angle of the blade to the tooth surface. At proper working angulation (less.than.90° but more than 45°), the lower shank of a.Gracey curette is parallel to the tooth surface being scaled. The lower shank of a universal curette would be tilted slightly toward the tooth.

Maximum shrinkage after gingival curettage can be expected from tissue that is: • fibrotic • edematous • fibroedematous • formed within an intrabony pocket 牙龈刮除术后最大收缩可以从组织中预期 是： •纤维化 •水肿 •纤维性 •在骨内口袋内形成

• edematous Indications for curettage are very limited. It can be used after scaling and root planing for the following purposes: 1. Curettage can be performed as part of new attachment attempts in moderately deep intrabony pockets located in accessible areas where a type of "closed" surgery is deened advisable. 2. Curettage can be done as a nondefmitive procedure to reduce inflammation before pocket elimination using other methods or when more aggressive surgical techniques (e.g., flaps) are contraindicated. 3. Curettage is also frequently performed on recall visits as a method of maintenance treatment for areas of recurrent inflammation and pocket depth. Contraindications of gingival curettage as a definitive procedure include: •™***^Acute periodontal inflammation • Firm, fibrotic tissue • Intrabony pockets • Mucogingival involvements • When the lateral gingival wall is extremely thin 1. Patients with edematous and granulomatous inflammation respond better to Notes curettage than do those with conditions of fibrous hyperplasia. 2. For a new attachment to occur: (1) An adequate number of undifferentiated mesenchymal cells must be present. (2) Complete removal of junctional and pocket epithelium must be accomplished. (3) The complete removal of calculus and/or altered cementum must be accomplished. Important: It is recommended that all students read The American Academy of Periodontology Statement Regarding Gingival Curettage. This can be found on the Internet at: http://www.perio.org/resources-products/pdf/38-curettage.pdf

Which of the following is the most common error when performing periodontal probing? I using the wrong type of probe incorrectly reading the periodontal probe • excessively angling the probe when inserting it interproximally beyond the long axis of the tooth • forgetting to also probe the lingual of every tooth 执行牙周探查时，最常见的错误是以下哪项？ 一世 使用错误的探头类型 不正确地读取牙周探针 •当探针插入超过长时间时，会使探头过度倾斜 牙齿的轴线 •忘记还要探测每只牙齿的舌头

• excessively angling the probe when inserting it interproximally beyond the long axis of the tooth *** This will give greater probe readings than are actually present. Tilting the probe could affect the accuracy of the measurements. If the probe is angled too much, it will extend beyond the contact area, and if it isn't angled enough, then it will be at the line angle instead of under the contact area. Both mistakes will result in inaccurate readings. The tip should be flat against the tooth near the gingival margin with the probe approximately parallel with the long axis of the tooth for insertion. Note: In the presence of inflammation, the probe may extend apical to.the most coronal extent of the junctional epithelium (bottom of pocket) and give a slightly greater depth than is actually present. Important: If a patient is at risk for subacute bacterial endocarditis, he or she needs to be premedicated before performing periodontal probing. ~\?^" Remember: Bacteremia can occur even with mastication or brushing. However, it does not last long. The important consideration is the presence or absence of periodontal inflammation. The presence of inflammation leads to a longer duration of bacteremia with resultant risks for patients at risk of acute bacterial endocarditis.

When evaluating an osseous defect, the only way to determine the number of walls left surrounding the tooth is by: periodontal probing radiographs exploratory surgery > testing for mobility 当评估骨质缺陷时，确定牙齿周围的墙壁数量的唯一方法是： 牙周探测 X光片 探索性手术 >测试移动性

• exploratory surgery *** This is because a dense buccal and/or lingual plate of bone will tend to mask the defect, blocking it out on the radiographs. This information can only be determined by exploratory surgery. Important: Radiographs will not show: 1 • The.number ofwajlsjeft surrounding the tooth 2. The exact configuration of the defect 3. The location of the epithelial attachment Remember: The two most critical parameters for the prognosis of a periodontally involved tooth are mobility and attachment loss (which is most critical). Angular defects are classified on the basis of the number of osseous walls. Angular defects may have one, two, or three walls. The number of walls in the apical portion of the defect may be greater than that in its occlusal portion, in which case the term "combined osseous" defect is used. Pocket depth is the distance between the base of the pocket and the gingival margin. The level of attachment, on the other hand, is the distance between the base of the pocket and a fixed point on the crown, such as the CEJ. Changes in the level of attachment can be caused only by gain or loss of attachment and thus provide a better indication of the degree of periodontal destruction. Pocket formation causes loss of attachment of the gingiva and denudation of the root surface. The severity of the attachment loss is generally, but not always, correlated with the depth of the pocket. This is because the degree of attachment loss depends on the location of the base of the pocket on the root surface, whereas the pocket depth is the distance between the base of the pocket and the crest of the gingival margin. Pockets of the same depth may be associated with different degrees of attachment loss and pockets of different depths may be associated with the same amount of attachment loss.

______are the most common cells in the peridontal ligament and appear as ovoid or elongated cells oriented along the principal fibers, exhibiting pseudopodialike processes. • cementoblasts • osteoblasts • fibroblasts • macrophages ______是周围韧带中最常见的细胞并出现 作为沿主要纤维取向的卵形或细长细胞，展现出来 伪伪迹过程。 •成熟细胞 •成骨细胞 •成纤维细胞 •巨噬细胞

• fibroblasts Types of cells identified in the periodontal ligament: • Connective tissue cells fvflrjroblasts, cignientoblasts, and osteoblasts. Fibroblasts are the most common cells; they synthesize collagen and possess the capacity to phagocytize "old" collagen fibers. Note: Cementoclasts and osteoclasts are also seen in the cemental and osseous surfaces of the PDL. • Epithelial rest cells: the epithelial rests of Malassez form a latticework in the PDL and are considered remnants of Hertwig root sheath, which disintegrates during root development. They are distributed close to the cementum throughout the PDL of most teeth and are most numerous in the apical and cervical areas. ^ • ^^ • Defense cells: includeWrtrophils, lymphocytes, macrophages, mast cells, and eosinophils. These cells, as well as those associated with neurovascular elements, are similar to the cells in other connective tissues. The functions of the periodontal ligament are categorized into: Physical: attachment of the tooth to the bone via principal fibers and the absorption of occlusal forces. Formative: formation of connective tissue components by activities of connective tissue cells (cementoblasts, fibroblasts, and osteoblasts). Remodeling: by activities of connective tissue cells that are able to form as well as resorb cementum (cementoblasts or cementoclasts), the PDL (fibroblasts orfibroclasts), and the alveolar bone (osteoblasts or osteoclasts). Nutritive: through blood vessels that maintain the vitality of its various cells. Sensory: carried by the trigeminal nerve, proprioceptive and tactile sensitivity is imparted through PDL (sensation of contact between teeth). Note: The PDL also contains a large proportion of ground substance, filling the spaces between the fibers and cells. It consists of two main components: glycosaminoglycans, such as hyaluronic acid jmd proteoglycans, and glycoproteins, such as/ibronectin and laminin. The PDL may also contain calcified masses called cementicles, which are adherent to or detached from the root surfaces. These develop from calcified epithelial rests.

Of the choices listed below, which one describes the boundaries that define the attached gingiva? > from the gingival margin to the interdental groove • from the free gingival groove to the gingival margin > from the mucogingival junction to the free gingival groove > from the epithelial attachment to the cementoenamel junction 在下列选项中，哪一个描述了界定附着的牙龈的界限？ 从牙龈边缘到牙间沟 •从免费的牙龈沟到牙龈边缘 从粘膜下龈交界处到自由的牙龈沟 >从上皮附着到胶质骨界面 109

• from the mucogingival junction to the free gingival groove (base of the sulcus) In an adult, normal gingiva covers the alveolar bone and tooth root to a level just coronal to the CEI. The gingiva is divided anatomically into marginal, attached, and interdental areas. • Marginal or unattached gingiva: is the terminal edge or border of the gingiva surrounding the teeth in collarlike fashion. In about 50% of cases, it is demarcated from the adjacent attached gingiva by a shallow linear depression, the free gingival groove. Usually about 1 mm wide, the marginal gingiva forms the. soft tissue wall of the gingival sulcus. • Attached gingiva: is continuous with the marginal gingiva. It is firm, resilient, and tightly bound to the underlying periosteum of alveolar bone. The facial aspect of the attached gingiva extends to the relatively loose and movable alveolar mucosa and is demarcated by the mucogingival junction. *** The width of the attached gingiva is an important clinical parameter. It is the distance between the mucogingival junction and the projection on the external surface of the bottom of the gingival sulcus or the periodontal pocket. It should not be confused with the width of the keratinized gingiva because the latter also includes the marginal gingiva. *** The width of the attached gingva on the facial aspect differs in different areas of the mouth. It is generally greatest in the incisor region and narrower in the posterior segments. *** Because the mucogingival junction remains stationary throughout adult life, changes in the width of the attached gingiva are caused by modifications in the position of its coronal portion. The width of the attached gingiva increases with age and in supraerupted teeth. • Interdental gingiva: occupies the gingival embrasure, which is the interproximal space beneath the area of tooth contact. The interdental gingiva can be pyramidal or can have a "col" shape. The shape of the gingiva in a given interdental space depends on the contact point between the two adjoining teeth and the presence or absence of some degree of recession. Note: "Stippling" of the attached gingiva refers to the irregular surface texture of the attached gingiva, similar to the surface of an orange peel. Stippling occurs at the intersection of epithelial ridges that causes the depression and the interspersing of connective tissue papillae between these intersections, giving rise to the small bumps.

The attachment apparatus is composed of all of the following EXCEPT one. Which one is the EXCEPTION! • periodontal ligament • cementum • alveolar bone • gingiva 附件装置由以下的全部除外。 哪一个是EXCEPTION！ •牙周韧带 •牙骨质 •牙槽骨 •牙龈 108

• gingiva The periodontium conists of the investing and supporting tissues of the tooth: gingiva, periodontal ligament, cementum, and alveolar bone. It has been divided into two parts: 1. Gingiva: the main function of which is protecting the underlying tissues 2. Attachment apparatus: composed of the: • Periodontal ligament • Cementum • Alveolar bone The cementum is considered a part of the periodontium because, with the bone, it serves as the support for the fibers of the periodontal ligament. The gingival fluid (sulcular fluid) contains components of connective tissue, epithelium, inflammatory cells, serum, and microbial flora inhabiting the gingival margin or the sulcus (pocket). In the healthy sulcus, the amount of gingival fluid is very small. During inflammation, however, the gingival fluid flow increases, and its composition starts to resemble that of an inflammatory exudate. The main route of the' gingival fluid diffusion is through the basement membrane, through the relatively wide intracellular spaces of the junctional epithelium, and then into the sulcus. The gingival fluid is believed to: • Cleanse material from the sulcus • Contain plasm'a proteins that may improve adhesion of the epithelium to the tooth • Possess antimicrobial properties • Exert antibody activity to defend the gingiva

Which type of pocket is formed by gingival enlargement without destruction of the underlying periodontal tissues? gingival pocket • periodontal pocket • suprabony pocket • intrabony pocket 131 牙龈扩大而不破坏形成哪种口袋 的基础牙周组织？ 牙龈口袋 •牙周袋 •suprabony口袋 •骨内口袋

• gingival pocket Deepening of the gingival sulcus may occur by coronal movement of the gingival margin, apical displacement of the gingival attachment, or a combination of the two processes. Pockets can be classified as follows: • Gingival pocket. (pseudopocket): this type of pocket is formed by gingival enlargement without destruction of the underlying periodontal tissues. All gingival pockets are suprabony (the base of the pocket is coronal to the crest of the alveolar bone). The sulcus is deepened because of the increased bulk of the gingiva. • Periodontal pocket: this type of pocket occurs with destruction of the supporting periodontal tissues. Progressive pocket deepening leads to destruction of the supporting periodontal tissues and loosening and exfoliation of the teeth. Two types of periodontal pockets exist: • Intrabony (infrabony, subcrestal, or intra-alveolar): in which the bottom of the pocket is apical to the level of the adjacent alveolar bone • Suprabony (supracrestal or supra-alveolar): in which the bottom of the pocket is coronal to the underlying alveolar bone. Clinical signs that suggest the presence of periodontal pockets include a bluish red, thickened marginal gingiva; a bluish red, vertical zone from the gingival margin to the alveolar mucosa; gingival bleeding and suppuration; tooth mobility, diastema formation; and symptoms such as localized pain or "pain deep in the bone." The only reliable method of locating periodontal pockets and determining their extent is careful probing of the gingival margin along each tooth surface.

__________are used selectively on line angle on negotiated with other strokes. • vertical strokes • oblique strokes • horizontal strokes • circular strokes __________在线角度上有选择地与其他笔画协商使用。 •垂直笔画 •倾斜笔画 •水平笔画 •圆形笔画

• horizontal strokes There are three basic strokes used during instrumentation. Any of these basic strokes may be activated by a pull or a push motion in a vertical, oblique, or horizontal direction. Vertical and oblique strokes are used the most frequently. Horizontal strokes are used selectively on line angles or deep pockets that can-not be negotiated with vertical or oblique strokes. The direction, length, pressure, and number of strokes necessary for either scaling or root planing are determined by four major factors: (1) gingival position and tone, (2) pocket depth and shape, (3) tooth contour, and (4) the amount and nature of the calculus or roughness., • Exploratory stroke: is a light, "feeling" stroke that is used with probes and explorers to evaluate the~dimensions of the pocket and to detect calculus and irregularities of the tooth surface. The instru-ment is grasped lightly and adapted with light pressure against the tooth to achieve maximal tactile sensitivity. • Scaling stroke: is a short, powerful pull stroke that is used with bladed instruments for the removal of both supragingival and subgingival calculus. The scaling motion should be initiated in the forearm and transmitted from the wrist to the hand with a slight flexing of the fingers. The scaling stroke is not initiated in the wrist or fingers nor is it carried out independently without the use of the forearm. • Root planing stroke: is a moderate to light pull stroke that is used for final smoothing and planing of the root surface. With a moderately firm grasp, the curette is kept adapted to the tooth with even, lateral pressure. A continuous series oflong, overlapping shaving strokes is activated. As the surface becomes smoother and resistance diminishes, lateral pressure is progressively reduced. 1. "Pulling" strokes are safer than "pushing" strokes because the push stroke may force cal-Notes cuius into the supporting tissues. The push stroke, especially in an apical direction, is not t recommended. 2. Probing stroke: upward and downward movement within a periodontal pocket. 3. The modified pen grasp is the most useful grasp for periodontal instrumentation. 4. The lower third of the working end, which is the last few millimeters adjacent to the toe or tip, must be kept in constant contact with the tooth while it is moving over the tooth. 5. For subgingival insertion of a bladed instrument such as a curette, angulation should be as close to 0 degree as possible. During scaling and root planing, optimal angulation is be-tween 45 and 90 degrees.

A/An_____ of the saliva causes precipitation of calcium phosphate salts by lowering the precipitation constants. • decrease in the pH • increase in the pH • decrease in the viscosity • increase in the viscosity 唾液中的A / A会导致磷酸钙的沉淀 降低沉淀常数的盐。 •pH降低 •增加pH值 •粘度降低 •粘度增加 122

• increase in the pH The theoretic mechanisms by which plaque becomes mineralized can be grouped into two main categories: 1 .Mineral precipitation results from a local rise in the degree of saturation of calcium and phosphate ions, which may occur through the following mechanisms: • An increase in the pH of the saliva causes precipitation of calcium phosphate salts by lowering the precipitation constants. The pHaaajUje_devated by the losj»of carbon dioxide and the fojaaation of ammonia by dental plaque bacteria. • Colloidal proteins in saliva bind calcium and phosphate ions and maintain a supersaturated solution with respect to calcium phosphate salts. With stagnation of saliva, colloids settle out, and the supersaturated state is no longer maintained, leading to precipitation of calcium phosphate salts. • Phosphatase liberated from dental plaque, desquamated epithelial cells, or bacteria precipitates calcium phosphate by hydrolyzing organic phosphates in saliva, thus increasing the concentration of free phosphate ions. 2. Seeding agents induce small foci of calcification that enlarge and coalesce to form a calcified mass. This concept is referred to as the epjtactic concept, or more appropriately, heterogenous jjLUcleation. It is suspected that the intercellular matrix of plaque plays an active role as the seeding agent. The carbohydrate-protein complexes may initiate calcification by removing calcium from saliva (chelation) and binding with it to form nuclei that induce subsequent deposition of minerals. Note: Mineralization of plaque starts extracellularly around both gram-positive and gram-negative organisms.(^acderion^^fsvd.yeillonella species have the ability to form intracellular hydroxyapatite crystals. Remember: Materia alba is a concentration of njjcroorganisms, dgsquamated epithelial cells, leukocytes, and amixture of salivary proteins and lipids, with few or no food particles, and it lacks the regular internal pattern observed in plaque.

How should a periodontal probe be adapted in an interproximal area? > it should be parallel to the long axis of the tooth at the point angle • it should be parallel to the long axis of the tooth at the contact area • it should touch the contact area and the tip should angle slightly beneath and beyond the contact area • it should be perpendicular to the long axis of the tooth in front of the contact area 在邻近地区应如何调整牙周探针？ >它应该在点角度处平行于牙齿的长轴 •应在接触区域平行于牙齿的长轴 •应接触接触区域，并且尖端应稍微倾斜到下方 接触面积 •它应该垂直于接触区域前面的牙齿的长轴

• it should touch the contact area and the tip should angle slightly beneath and beyond the contact area *** The periodontal probe may be angled approximately 10° on each interproximal surface so that the tip of the probe is placed apical to the contact point of adjacent teeth and may detect any interdental crater, but, in most instances, the direction of the probing is parallel to the long axis of the tooth. Periodontal measurements are taken by inserting the probe under the marginal gingiva and gently moving it down to the junctional epithelium (feels soft, elastic, and resilient). In a healthy site, the tip of the probe stops within the junctional epithelium and, in a diseased site, it penetrates into the connective tissue. In severe disease, the probe tip may penetrate to the alveolar bone. 1. The clinical probing depth is always greater than the histologic sulcus or Notes pocket depth. Probing accuracy is only within +/- 1 mm. 2. The calibrated periodontal probe should have a tapered shaft approximately 0.5 mm in diameter at the tip. It is important to have uniform instruments throughout the practice to ensure as much standardization as possible. 3. Furcation areas can be best evaluated with the curved #2 Nabers probe. t%/Yh& periodontal probe can also be useful in the detection of subgingival deposits.

When using the periodontal probe to measure pocket depth, the measurement is taken from the: • base of the pocket to the CEJ • free gingival margin to the CEJ • junctional epithelium to the margin of the free gingiva « base of the pocket to the mucogingival junction 当使用牙周探针测量口袋深度时，进行测量 取自： •口袋底座到CEJ •CEJ免费牙龈边缘 •连接上皮到自由牙龈边缘 口袋的基部到粘膜下龈交界处

• junctional epithelium to the margin of the free gingiva Periodontal probes are used to measure the depth of pockets and to determine their configurations. The typical probe is a tapered, rodlike instrument calibrated in millimeters, with a blunt, rounded tip. Ideally, probes are thin, and the shank is angled to allow easy insertion into the pocket. The probe is inserted along the long axis of the tooth into the pocket with a firm, gentle pressure (approximately 10 to 20 grams) until resistance is met. The probe is walked around each surface of the tooth. This method is less painful and more efficient, provides a complete and accurate assessment of the depth of the epithelial attachment and will detect bony defects better. Periodontal probing provides the most accurate assessment of periodontal pocket depth. The true topography of vertical osseous defects cannot be determined by radiographic examination alone. Bone levels may be high, yet pockets may be deep. Extensive bone loss may exist and, yet, be unaccompanied by pockets if the gingiva has receded. The most important reason for using the periodontal probe is that it determines the loss of attachment. 1. Bleeding scores: bleeding is still the most reliable indicator of the presence Notes of gingival or periodontal inflammation. ISftW 2. Plaque score: with plaque disclosing solution, used to help visualize plaque for the patient and clinician. Also used at multiple visits to show patients improvement in their level of oral hygiene. 3. Recession is measured in millimeters from the CEJ to the marginal gingiva of each tooth root.

If you should meet resistance after inserting the periodontal probe into the sulcus, you should: remove the probe and reinsert it in a different spot lift the probe away from the tooth and attempt to move it apically force the probe beyond the obstruction remove the probe and select one with a narrower diameter record the measurement where the probe stopped 如果在将牙周探针插入龈沟后遇到阻力，应该： 移除探头并将其重新插入到不同的位置 将探头提起离开牙齿，并尝试顶部移动 迫使探头超出阻塞 取下探头并选择一个较窄的直径 记录探头停止的测量

• lift the probe away from the tooth and attempt to move it apically Often when probing, the passage of the probe may be blocked by a hard, unyielding ledge. This is usually calculus. Gently lift the probe away from the tooth, placing it against the tissue wall of the pocket and attempt to proceed apically again. If the obstruction was indeed calculus and it has now been bypassed, then the probe should now move deeper into the pocket until the junctional epithelium is reached. The tip of the probe should be placed back against the tooth once the obstruction has been bypassed. Remember: The probe should be inserted parallel to the vertical axis of the tooth and "walked" circumferentially around each surface of each tooth to detect the areas of deepest penetration. 1. Recession is the measurement of the migration of the free gingival margin Notes apical to the CEJ of the tooth. Recession is measured as a positive value. The recession measurement added to probe depth at a particular site indicates the amount of periodontal attachment that has been lost at that site. When the gingival margin is coronal to the CEJ, the recession measurement has a negative value. 2. To measure the amount of attached gingiva: (1) Place the probe on the external surface of the gingiva and measure from the mucogingival junction to the gingival margin to determine the width of the total gingiva. (2) Insert the probe and measure probing depth. (3) Subtract the probing depth from the total gingival measurement to get the width of the attached gingiva.

Ultrasonic instrumentation is accomplished with a: • heavy touch and light pressure, keeping the tip perpendicular to the tooth surface and constantly in motion • light touch and heavy pressure, keeping the tip parallel to the tooth surface and stationary • light touch and light pressure, keeping the tip parallel to the tooth surface and constantly in motion • heavy touch and heavy pressure, keeping the tip perpendicular to the tooth surface and stationary 超声波仪器用a： •重的触感和轻微的压力，保持尖端垂直于牙齿表面 并不断运动 •轻触和重压，保持尖端平行于牙齿表面并静止 •轻巧轻盈的压力，保持尖端平行于牙齿表面并持续 在运动 •重的触感和重的压力，保持尖端垂直于牙齿表面 和静止

• light touch and light pressure, keeping the tip parallel to the tooth surface and constantly in motion Ultrasonic instruments have been widely used as a valuable adjunct to conventional hand instrumentation for many years. The selection of either ultrasonic or hand instrumentation should be determined by the clinician's preference and experience and the needs of each patient. The success of either treatment method is determined by the time devoted to the procedure and the thoroughness of root debridement. In practice, clinicians typically use a combination of both ultrasonic and hand instrumentation to achieve thorough debridement. Ultrasonic instrumentation is accomplished with a light touch and light pressure, keeping the tip parallel to the tooth surface and constantly in motion. Leaving the tip in one place for too long or using the point of the tip against the tooth can produce gouging and roughening of the root surface or overheating of the tooth. The working end of the ultrasonic instrument must come in contact with the calculus deposit to fracture and remove it. The working tip must contact all aspects of the root surface to remove plaque and toxins thoroughly. Although as much as 1 Ommor more of the length of the ultrasonic tip vibrates, only a small portion of it can be adapted to contact the curved root surface at any one time or point. As with hand instruments, a series of focused, overlapping strokes must be activated to ensure complete root coverage. Important: Subgingival root surface roughness does not seem to interfere with healing after scaling and root planing. Thus, it does not appear useful to reinstrument root surfaces with hand instruments after a clinically detectable smooth surface has been created with sonic or ultrasonic scaler. Contraindications to the use of ultrasonic and sonic scaling devices: ^-01der cardiac pacemakers vMSiown communicable diseases that can be transmitted by aerosols ^Patients at risk for respiratory disease, including patients who are immunosuppressed or have chronic pulmonary disorders •^Patients with titanium implants, porcelain or bonded restorations (unless you use plastic- tipped inserts)

dental plaque is composed primarily of: • microorganisms • water • minerals • tissue cells 牙斑主要由以下组成： •微生物 • 水 •矿物质 •组织细胞 124

• microorganisms Dental plaque is defined clinically as a structured, resilient, yellow-grayish substance that adheres tenaciously to the intraoral hard surfaces, including removable and fixed restorations. Plaque is primarily composed of bacteria in a matrix of salivary glycoproteins and extracellular polysaccharides. The micoroorganisms exist within an intercellular matrix that also contains a few host cells, such as epithelial cells, macorphages, and leukocytes. Dental plaque is broadly classified as: •\Supragingival plaquejfis found at or above the gingival margin; when in direct contact with the gingival margin" it is referred to as marginal plaque. Gram-positive cocci and short rods predominate at the tooth surface, whereas gram-negative rods and filaments, as well as spirochetes, predominate in the outer surface of the mature plaque mass. •..Subgingival plaque: is found below the gingival margin, between the tooth and the gingival pocket epithelium. In general, the subgingival microbiota differs in composition from the supragingival plaque, primarily because of the local availability of blood products and the low oxidation-reduction (redox) potential, which characterizes the anaerobic environment. • Cervical plaque: - Tooth associated: gram-positive rods and cocci - Tissue associated: gram-negative rods and cocci, filaments, flagellated rods, and spirochetes • Deeper parts of the pocket: - Tooth associated: gram-negative rods - Tissue associated: gram-negative rods, flagellated rods, and spirochetes. Filamentous organisms become fewer. Key point:The composition of the subgingival plaque depends on the pocket depth. The apical part is dominated by spirochetes, cocci, and rods, whereas in the poronaLpart, more filaments are observed. Important: The overall pattern observed in dental plaque development shows a shift from the early aerobic environment characterized by gram-positive facultative species to a highly oxygen-deprived environment in which gram-negative anaerobic microorganisms predominate.

The narrowest band of attached gingiva is found: on the lingual surfaces of maxillary incisors and the facial surfaces of maxillary first molars • on the facial surfaces of mandibular second premolars and the lingual surface of canines • on the facial surfaces of the mandibular canine and first premolar and the lingual surfaces adjacent to the mandibular incisors and canines • none of the above 发现附着的牙龈的最窄的带： 在上颌门牙的舌表面和上颌的面部表面 第一磨牙 •在下颌第二前磨牙和舌侧表面上 犬 •在下颌犬和第一前磨牙和舌头的面部表面 与下颌门牙和犬相邻的表面 • 以上都不是

• on the facial surfaces of the mandibular canine and first premolar and the lingual surfaces adjacent to the mandibular incisors and canines *** Narrow gingival zones may occur also at the mesiobuccal root of maxillary first molars, associated with prominent roots and sometimes with bony dehiscences, and at the mandibular third molars. The width of the attached gingiva is determined by subtracting the sulcus or pocket depth from the total width of the gingiva (gingival margin to mucogingival line). This is done by stretching the lip or cheek to demarcate the mucogingival line while the pocket is being probed. The amount of attached gingiva is generally considered to be insufficient when stretching of the lip or cheek induces movement of the free gingival margin. The width of the attached gingva on the facial aspect differs in different areas of the mouth. It is generally greatest in the incisor region (3.5-4.5 mm in maxilla, 3.3-3.9 mm in mandible), and narrower in the posterior segments (1.9 mm in maxillary and 1.8 mm in mandibular first premolars) ."*'* Important: A "functionally adequate" zone of gingiva is defined as one that is keratinized, firmly bound to tooth and underlying bone,*about 2.0 mm or more in width, and resistant to probing and gaping when the lip or cheek is distended. 1. The "attached" gingiva is structured to withstand frictional stresses of mas- Notes tication and brushing. 2. The alveolar mucosa appears to be well adapted to permit movement but is not able to withstand frictional stresses.

How should the periodontal probe be inserted into the sulcus? • perpendicular to the long axis of the tooth • with a firm pushing motion • with a short oblique stroke • parallel to the tooth surface 如何将牙周探针插入沟中？ •垂直于牙齿的长轴 •坚定推动 •短斜行程 •平行于牙齿表面

• parallel to the tooth surface The tip of the probe should always be kept in contact with the tooth, thus preventing soft tissue injury. The probe is gently "walked" along the junctional epithelium in an up-anddown motion (called circumferential probing), always remaining under the gingival margin. It is imperative that the probe be walked along the entire gingival sulcus since the depth of the epithelial attachment varies. Six measurements are recorded - three from the buccal and three from the lingual: distobuccal, buccal, mesiobuccal, distolingual, lingual, and mesiolingual. These measurements are the distance in millimeters from the base of the pocket (junctional epithelium) to the margin of the free gingiva. 1 .The most important reason for using the periodontal probe is that it deter- Notes mines the loss of attachment. These measurements are taken both before and after scaling and root planing procedures to evaluate the tissue response and the effectiveness of treatment. 2. Probing is performed with firm, gentle pressure. The correct probe force (approximately 10 to 20 grams) depresses the thumb pad approximatelyJ_mmJo 2 mm.

Furcation involvements have been classified as grades I, II, III, and IV according to the amount of tissue destruction. Grade II is: • incipient bone loss • partial bone loss (cul-de-sac) > total bone loss with through-and-through opening of the furcation • similar to the above, but with gingival recession exposing the furcation to view 根分叉病变已经I，根据II，III，和IV划分为等级 到组织破坏的量。 二级是： •初期骨质流失 •部分骨质流失（死亡） >通过开通分叉的总骨丢失 •与上述相似，但牙龈退缩暴露分叉视野

• partial bone loss (cul-de-sac) The term furcation involvement refers to the invasion of the bifurcation and trifurcation of multirooted teeth by periodontal disease. The denuded furcation may be visible clinically or covered by the wall of the pocket. The extent of involvement is determined by exploration with a blunt probe, along with a simultaneous blast of warm air to facilitate visualization. Furcation involvements have been classified as grades I, II, III, and TV according to the amount of tissue destruction. • Grade I: is incipient bone loss • Grade II: is partial bone loss (cul-de-sac) • Grade III: is total bone loss with through-and-through opening of the furcation • Grade IV: is similar to Grade III, but with gingival recession exposing the furcation to view Findings that complicate furcation involvement and account for some painful symptoms include caries of the cementum and dentin, tooth resorption in the furcation, abscess formation • llX'ri"lll'l*l"l'r"* I^TM—«^MI"H l—'l * M1" "ft r* Ill"" I I Mil MM fill II !•••!! ' in the furcation, and involvement of the pulp via lateral canals in the furcation. Definitive diagnosis of furcation involvement is made by careful clinical probing. X-rays are helpful but only as an adjunct to the clinical examination. The major principle of treatment of involved furca is to eliminate the involvement whenever possible. A variety of methods are available for treatment. Not all of them provide for elimination of the furcation; some provide only for increased accessibility for plaque removal. Bone grafts have relatively little effectiveness in treating furcations. However, guided tissue regeneration is used to treat Grade II furcations with good success. Note: Furcation involvement of maxillary second molars have the poorest prognosis following therapy- f-f^' Important: Microscopically, furcation involvement presents no unique pathologic features. It is simply a phase in the rootward extension of the periodontal pocket.

Specific bacteria are implicated in periodontal disease and are commonly found at the site of infection. The Red complex bacteria consist of the following. Select all that apply. • porphyromonas gingivalis • tannerella forsythia • treponema denticola • eikenella corrodens 具体细菌参与 牙周病，常见于感染部位。 红色复合细菌由以下组成。 选择所有符合条件的。 •牙龈卟啉单胞菌 •连翘连翘 •齿垢密螺旋体 •eikenella corrodens 126

• porphyromonas gingivalis tannerella forsythia •Treponema denticola Recent sudies of plaque samples looking for 40 subgingival microorganisms using a DNA hybridization methodology, defined "complexes" of periodontal microorganims. The composition of the different complexes was based on the frequency with which different clusters of microorganisms were recovered. The early (primary) colonizers are either independent of defined complexes (Actinomyces naeslundii, A. viscosus) or members of the yellow (Streptococcus spp.) or purple complexes (Actinomyces odontolyticus). The microorganisms primarily considered secondary (late) colonizers fell into the green, orange or red complexes. The green complex includes Eikenella corrodens, Actinobacillus actinomycetemcomitans serotype a, and Capnocytophaga species. The orange complex includes Fusobacterium, Prevotella, and Campylobacter species. The green and orange complexes include species recognized as pathogens in periodontal and nonperiodontal infections. The red complex consists of Porphyromonas gingivalis, Treponema denticola, and Tannerella forsythia. This complex is of particular interest because it is associated with bleeding on probing, which is an important clinical parameter of destructive periodontal diseases. Plaque as a biofllm: The dental plaque biofilm has a similar structure to all biofilms (composed of microcolonies encased in a polysaccharide matrix). It is heterogenous in structure, with clear evidence of open fluidfilled channels running through the palque mass. These water channels permit the passage of nutrients and other agents throughout the biofilm, acting as a primitive "circulatory" system. The intercellular matrix consists of organic and inorganic materials derived from saliva, gingival crevicular fluid, and bacterial products. Important: In a biofilm, bacteria have the capacity to communicate with each otherfcalled quorum sensing).: This involves the regulation of expression of specific genes through the accumulation of signaling compounds that mediate intercellular communication. When these signaling compounds reach a threshold level (called quorum cell density), gene expression can be activated. Note: The high density of bacterial cells in a biofilm also facilitates the exchange of genetic information among cells of the same species and across species and even genera. Conjugation, transformation, plasmid transfer, and transposon transfer have all been shown to occur more easily in a biofilm. Remember: Following a prophy, plaque is most likely to accumulate on the interproximal tooth surfaces first.

To date, the ADA has accepted two agents for treatment of gingivitis, these are: • prescription solutions of chlorhexidine digluconate oral rinse • prescription solutions of tetracycline oral rinse • nonprescription essential oil oral rinse • nonprescription solutions of penicillin oral rinse 迄今为止，ADA已接受两种治疗牙龈炎的药物，分别是： •氯己定二葡萄糖酸口服冲洗液的处方溶液 •四环素口服冲洗液的处方溶液 •非处方精油口服冲洗 •青霉素口服冲洗的非处方溶液

• prescription solutions of chlorhexidine digluconate oral rinse • nonprescription essential oil oral rinse The agent that has shown the most positive antibacterial results to date is chlorhexidine, a diguanidohexane with pronounced antispetic properties. The 0.12% chlorhexidine digluconate preparation available in the United States for reducing plaque and gingivitis has been shown to be equally effective as the higher-concentration product (0.2%, aqueous solution). Localized, reversible side effects of chlorhexidine use may occur; primarily brown staining of the teeth, tongue, and silicate and resin restorations and transient impairment of taste perception. Chlorhexidine has very low sytemic toxic activity in humans, has not produced any appreciable resistance of oral microorganisms, and has not been associated with teratogenic alterations. Note: 0.12% chlorhexidine contains 12% alcohol Chorhexidine's effectiveness may be explained by the fact that it leaves the greatest residual concentration in the mouth after its use. It is approved by the ADA as an antimicrobial and antigingivitis agent. Examples include: Peridex and Periogard. Important: Substantivity is the ability of drugs to adsorb onto and bind to soft and hard tissues. The substantivity of chlorhexidine was first described in the 1970s. Due to this property, chlorhexidine can maintain effective concentration for prolonged periods of time. Essential oil mouth rinses contain thymol, eucalyptol, methanol, and methyl salicylate. These products also contain alcohol (up to 24% depending on the preparation). An example is I^isterine. A product containing triclosan has shown some effectiveness in reducing plaque and gingivitis. It is available in toothpaste form, and the active ingredient is more effective in combination with zinc citrate or a copolymer of methoxyethylene. Other oral rinse products on the market have shown some evidence of plaque reduction, although long-term improvement in gingival health has not been substantiated. These include stgjjnous fluoride, cejylpyridinium chloride (quaternary ammonia compounds), and s^aguinarine.

The source of mineralization for supragingival calculus is: • desquamated epithelial cells • gingival crevicular fluid • phosphatases formed by bacterial plaque • saliva 龈上结石的矿化来源是： •脱屑上皮细胞 •牙龈沟液 •由细菌斑块形成的磷酸酶 • 唾液

• saliva Calculus is dental plaque that has undergone mineralization. It forms on the surfaces of natural teeth and dental prostheses. Saliva is the source of mineralization for supragingival calculus, whereas the serum transudate called gingival crevicular fluid furnishes the minerals for subgingival calculus. • Supragingival calulus: is located coronal to the gingival margin. It is usally white or pale yellow in color and is hard with a claylike consistency. It is easily removed by a professional cleaning. The two most common locations for supragingival calculus to develop are the buccal surfaces of the maxillary molars and the lingual surfaces of the mandibular anterior teeth. Saliva from the parotid gland flows over the facial surfaces of the maxillary molars through Stensen duct, whereas the orifices of Wharton duct and Bartholin duct empty onto the lingual surfaces of the mandibular incisors from the submandibular and sublingual glands, respectively. • Subgingival calculus: is located below the crest of the marginal gingiva. It is typically hard and dense and frequently appears dark brown or greenish black (due to exposure to gingival crevicular fluid) while being firmly attached to the tooth surface. Differences in the manner in which calculus is attached to the tooth surface affect the relative ease or difficulty encountered in its removal. It has been shown that calculus can attach to tooth surfaces through four modes: L Attachment by.means of an organic pellicle on enamel: most common mode 2. Mechanical locking into surface irregularities 3. Close adaptation of calculus undersurface depressions to the gently sloping mounds of the unaltered cementum surface 4. Penetration of calculus bacteria into cementum Important: A reduction in gingival inflammation and probing depths with a gain in clinical attachment can be observed after removal of subgingival plaque and calculus.

Air is used to deflect the free gingival margin to detect: • the CEJ • smooth root surfaces • subgingival calculus • inflammation 空气用于偏转自由牙龈边缘以检测： •CEJ •光滑的根表面 •龈下结石 •炎症

• subgingival calculus One of the uses of the air syringe is to detect calculus, both supra- and subgingival. Supragingival calculus is often seen more easily when it is dry (saliva often conceals it), and deflecting the free gingival margin slightly makes subgingival calculus easier to de-tect. When using the explorer to detect calculus, a light instrument grasp should be utilized to increase tactile sensitivity. The lateral side of the tip of the instrument should be placed in contact with the tooth surface when exploring for calculus. Dried calculus is easier to detect than wet calculus with the explorer because it is less slippery.

The primary function of which instrument is to fracture or crush large deposite of tenacious calculus? • hoe scalers • files • chisel scalers • quetin furcation curettes 仪器的主要功能是破碎或粉碎顽固演算的大量沉积物？ •锄头定型机 •文件 •凿子 •昆汀分叉治疗

• subgingival calculus One of the uses of the air syringe is to detect calculus, both supra- and subgingival. Supragingival calculus is often seen more easily when it is dry (saliva often conceals it), and deflecting the free gingival margin slightly makes subgingival calculus easier to de-tect. When using the explorer to detect calculus, a light instrument grasp should be utilized to increase tactile sensitivity. The lateral side of the tip of the instrument should be placed in contact with the tooth surface when exploring for calculus. Dried calculus is easier to detect than wet calculus with the explorer because it is less slippery. • files The five basic scaling instruments are as follows:> •(Curette) the curette is the instrument of choice for removing deep subgingival calculus, root planingVrtered cementum, and removing the^stoft tissue lining the periodontal pocket. Each working end has a cutting edge on both sides of the blade and a rounded toe. The curette is finer than the sickle scalers and does not have any sharp points or corners other than the cutting edges of the blade. Therefore, curettes can be adapted and provide good ac-cess to deep pockets with minimal soft tissue damage. -• Sickle sc&ler&supragingival scalers): have a flat surface and two cutting edges that con-verge in a sharply pointed tip. The shape of the instrument makes the tip strong so that it will not break off during use. The sickle scaler is used primarily to remove supragingival cal-culus. r- * Files: have a series of blades on a base. Their primary function is to fracture or crush large deposits of tenacious calculus or burnished sheets of calculus. Files" can easily gouge and roughen root surfaces when used improperly. Therefore, they are not suitable for fine scal-ing and root planing. '•Chisel scalers:, are designed for the proximal surfaces of teeth too closely spaced to per-mit the use of other scalers and are usually used in the anterior part of the mouth. They are double-ended instruments with a curved shank at one end and a straight shank at the other; the blades are slightly curved and have a straight cutting edge beveled at 45 degrees. The chisel is inserted from the facial surface. The instrument is activated with aEushnujtion, while the side of the blade is held firmly against the root. |jT.oe scalerp are used for scaling.ofled^esjjrringsof calculus. The blade is bent at a 99-degree angle; the cutting edge is formed by the junction of the flattened terminal surface with the inner aspect of the blade. The cutting edge is beveled at 45 degrees. Note: McCall's #3, 4, 5, 6, 7, and 8 are a set of six hoe scalers designed to provide access to all toomsurfaces. Each instrument has a different angle between the shank and handle.

The effectiveness of toothbrushing is best measured by: • the amount and location of plaque • the caries experience • the toothbrushing frequency • the condition of the toothbrush 刷牙的有效性最好是通过： •斑块的数量和位置 •龋齿经验 •刷牙频率 •牙刷的状况

• the amount and location of plaque Over the years, many different toothbrushing methods have been described and promoted as being efficient and effective. These methods can be categorized primarily according to the pattern of motion when brushing and are primarily of historical interest, as follows: • Roll: Roll method or modified Stillman technique • Vibratory: Stillman, Charters, and Bass techniques • Circular: Fones technique • Vertical: Leonard technique • Horizontal: Scrub technique Studies evaluating the effectiveness of the most common techniques have demonstrated no clear superiority for any method. The scrub technique is probably the simplest and most common method of brushing. Patients with periodontal disease are most frequently taught a sulcular brushing technique using a vibratory motion to improve access in the gingival areas. The method most often recommended is the Bass technique because it emphasizes sulcular placement of bristles. Bass method: • Place toothbrush so that the bristles are angled approximately 45 degrees from the tooth surfaces. This allows the bristles to extend into the gingival sulcus when pressure is applied to the brush in a horizontal direction. • Start at the most distal tooth in the arch, and use a vibratory, back-and-forth motion to brash Other methods of brushing, such as the modified Stillman and Charters, are variations of the Bass technique also designed to achieve thorough plaque removal at the gingival margins. They emphasize stimulation of the gingival circulation, which has not been demonstrated to achieve healing results beyond those achieved by good plaque removal. Important: No matter what toothbrushing method is chosen, the manual toothbrush should have soft nylon bristles and a small head. They should be replaced about every 3 months. . °.,

In intrabony pockets: • the bone loss is vertical in nature • the bone loss is horizontal in nature • transseptal fibers are horizontal • supracrestal fibers follow the normal bone contour 在骨内口袋： •骨质量的损失是垂直的 •骨质量下降是水平的 •经纤维纤维是水平的 •超临界纤维遵循正常的骨骼轮廓

• the bone loss is vertical in nature A B C Different types

The principal fibers of the periodontal ligament are arranged in four groups. The molecular configuration of collagen fibers in the periodontal ligament provides them with a tensile strength greater than that of steel. • both statements are true • both statements are false • the first statement is true, the second is false • the first statement is false, the second is true 牙根韧带的主要纤维分为四组。 胶原纤维在牙周膜中的分子构型 为它们提供比钢更大的拉伸强度。 •两个声明都是真实的 •两个语句都是假的 •第一个陈述是真实的，第二个是假的 •第一个陈述是假的，第二个是真的

• the first statement is false, the second is true The most important elements of the periodontal ligament are the principal fibers, which are collagenous and arranged in bundles and follow a wavy course when viewed in longitudinal section. The terminal portions of the principal fibers that are inserted into cementum and bone are termed Sharpey fibers. The principal fibers of the periodontal ligament are arranged in six groups that develop sequentially in the developing root: •JTranssegtal fibers: extend interproximally over the alveolar bone crest and are embedded in the cementum of adjacent teeth. These fibers keep all the teeth aligned (they maintain the integrity of the dental arches). Note: These fibers may be considered as belonging to the gingivTrJeTaTise ""mey'do not haveosseous attachment. » Alveolar crest fibers: extend obliquely from the cementum just beneath the junctional epithelium to the alveolar crest. These fibers prevent the extrusion of the tooth and resist lateral tooth movements. • Horizontal fibers: extend at right angles to the long axis of the tooth from the cementum to the alveolar bone. •jOblique fibers: the largest group in the periodontal ligament, they extend from the cementum in a coronal direction obliquely to the bone. They bear the brunt of vertical masticatory stresses and transform them into tension on the alveolar bone. • Apical fibers: radiate in a rather irregular manner from the cementum to the bone at the apical region of the socket. They do not occur on incompletely formed roots. • Tjiterradicular fibers: fan out from the cementum to the tooth in the furcation areas of multirooted teeth. Note: Small collagen fibers associated with the larger principal collagen fibers have been found. These fibers run in all directions, forming a plexus called the indifferent fiber plexus. Important: The molecular configuration of collagen fibers provides them with a tensile strength greater than that of steel. Consequently, collagen imparts a unique combination of flexibility and strength to the tissues.

Cervical line contours are closely related to the attachment of the gingiva at the neck of the tooth. The greatest contour of the cervical lines and gingival attachments occur on: • the distal surface of anterior teeth • the distal surface of posterior teeth • the mesial surface of anterior teeth • the mesial surface of posterior teeth 宫颈线轮廓与牙龈附着密切相关 牙齿的颈部。 宫颈线和牙龈的最大轮廓 附件发生在： •前牙远端表面 •后牙的远端表面 •前牙的中间表面 •后牙的中间表面

• the mesial surface of anterior teeth *** The mesial surface of the maxillary central has the greatest curvature. All teeth generally have a greater proximal cervical line (CEJ) curvature on the mesial than the distal. Also, the proximal cervical line (CEJ) curvatures are greater on the incisors and tend to get smaller when moving toward the last molar, where there may be no curvature at all. The cementoenamel junction of all teeth curves in two directions: • Toward the apex on the facial and lingual surfaces • Away from the apex on the mesial and distal surfaces In the absence of periodontal disease, the configuration of the crest of the interdental alveolar septa is determined by the position of the CEJ on adjacent teeth. The width of the interdental alveolar bone is determined by the tooth form present. Relatively flat proximal tooth surfaces call for narrow septa, whereas in the presence of an extremely convex tooth surface, wide interdental septa with flat crests are found.

Angular defects are classified on the basis of: • the number of osseous walls that were destroyed by periodontal disease • the number of osseous walls left surrounding the tooth • the number of osseous walls that will remain after surgery • periodontal probe readings 角度缺陷的分类依据是： •被牙周病破坏的骨壁数量 •围绕牙齿的骨壁数量 •手术后遗留的骨壁数量 •牙周探针读数

• the number of osseous walls left surrounding the tooth Horizontal bone loss is the most common pattern of bone loss in periodontal disease. The bone is reduced in height, but the bone margin remains approximately perpendicular to the tooth surface. The interdental septa and facial and lingual plates are affected, but not necessarily to an equal degree around the same tooth. Vertical or angular defects are those that occur in an oblique direction, leaving a hollowed-out trough in the bone alongside the root; the base of the defect is located apical to the surrounding bone. In most instances, angular defects have accompanying intrabony periodontal pockets; intrabony pockets, however, always have an underlying angular defect. Angular defects are classified on the basis of the number of osseous walls. Angular defects may have one, two, or three walls. The number of walls in the apical portion of the defect may be greater than that in its occlusal portion, in which case the term "combined osseous defect" is used. Important: Surgical exposure is the only sure way to determine the presence and configuration of vertical osseous defects. 1. Osseous craters are concavities in the crest of the interdental bone confined within the fac- Notes i a l a n a lingual walls. Craters have been found to make up about one-mird (35.2%,) of all defects and about two-third_s (62%) of all mandibulardefects. They are more common in postterior segments tKarTTrTanterlor segments. They are best treated with osseous surgery (recontouring). 2.The relative degree of success of periodontal bone grafting is reported to vary directly with the number of bony walls of the defect (vascularized, osseous surface area) and inversely with the surface area of the root against which the graft is implanted. Thus, a narrow, threewalled angular defect usually yields the greatest succsess, a two-walled defect the next best, and a one-walled defect the least. 3. A dehiscence is a loss of the buccal or lingual bone overlaying the root portion of a tooth, leaving the area covered by soft tissue only. 4. The three-wall vertical defect was originally called an intrabony defect. The term "intrabony" was later expanded to designate all vertical defects. 5. The one-wall vertical defect is also called a hemiseptum. iprabony pockets are associated with horizontaU?one loss. Tijexar^jyEryrrtaossMus.

The main objective of root planing is: • to remove chronically inflamed tissues • to change the bacterial microflora • to remove etiologic agents from the root surface • to eliminate pockets 根面平整术的主要目的是： •去除长期发炎的组织 •改变细菌菌群 •从根表面去除病原体 •消除口袋

• to remove etiologic agents from the root surface The major objective of scaling and root planing is to remove etiologic agents that promote gingival inflammation in the periodontal tissues. Removal of plaque, calculus, and endotoxins results in a subsequent shift from disease-associated, gram-negative anaerobes to health-associated, gram-positive, facultative microorganims. Important: By providing smooth root surfaces, there will be a reduced potential for bacterial accumulation, which is done in an attempt to achieve soft-tissue reattachment. Scaling and root planing are techniques of instrumentation applied to the root surface to divest it of plaque, calcified deposits, and softened or roughened cementum. When thoroughly performed, techniques produce a smooth, clean, hard polished root surface. Scaling with root planing is the primary treatment for periodontal inflammation. In simple cases, this treatment is useful in reducing shallow pockets and reducing the number of bacteria within these shallow pockets and may be the only treatment necessary. In severely advanced periodontal disease where surgery may not be possible, scaling with root planing is the only treatment feasible. Since the removal of plaque and deposits is the definitive treatment for periodontal inflammation, scaling with root planing is more frequently used than any other type of therapy. The most effective instrument for subgingival scaling and root planing is a sharp curette. They are generally smaller than scalers and are designed to permit atraumatic entry to the subgingival space. The tactile sensitivity of most curettes is greater than scalers, and, as such, curettes are well suited for subgingival calculus detection, calculus removal, and root planing. Each working end has a cutting edge on both sides of the blade and a rounded toe. There are two basic types of curettes: universal and area-specific (Gracey curettes). Double-ended Gracey curettes are paired in the following manner: • Gracey #1-2 and 3-4: anterior teeth • Gracey #5-6: anterior teeth and premolars • Gj^Ci^4Cfi^-affldJi=lfl^4ios.texka:Jeeth:.facial and lingual surfaces • Gracey #11-12: posterior teeth: mesial surface • Gracey #13-14:posterior teeth: distal surface Extended-shank curettes: have a longer terminal shank, a thinned blade, and a large-diameter terminal shank. They are available in finishing for light scaling) or rigid (for removal of heavy or tenacious calculus) designs. Mini-bladed curettes: have shorter blades (half the length) that allow easier insertion and adaptation. Gracey curvettes: are mini-bladed curettes with a more curved blade. Langer and mini-Langer curettes: combine the shank design of Gracey curettes with the universal blade design (90-degree angle of the face and lower shank).

Which of the following presents the most difficulty in performing a thorough scaling and root planing? • mesial surfaces of maxillary premolars • proximal surfaces of mandibular incisors ' triturations of maxillary molars distal surfaces of mandibular molars 以下哪一项表现最为困难的一个是彻底的 缩放和根刨？ •上颌前磨牙的中间表面 •下颌门牙近端表面 上颌磨牙研究 下颌磨牙的远端表面

• trifurcations of maxillary molars Mesial surfaces of maxillary premolars and the proximal surfaces of mandibular incisors are most likely to have flutings. Also, root proximity is a major problem when performing scaling and root planing on mandibular incisors.. Trifurcations on maxillary first molars are the most difficult of all to root plane. *** Key point: anatomic features of teeth frequently limit the effectiveness and efficiency of calculus removal. Remember: If, while root planing, you find only a thin ring of calculus in the bottom third of a deep pocket, you can assume that the calculus previously extended the full length of the pocket but the top part was previously removed. Likewise, if, after scaling and root planing, the patient returns in 1 week with hard, black deposits of calculus around the gingival margin, this indicates that a reduction in inflammation occurred after the procedure and old calculus is now exposed. 1. The best criterion to evaluate the success of scaling and root planing is no ev- Notes idence of bleeding on probing. Remember: Bleeding on probing indicates inflammation in the tissue. The amount of inflammation present is used to determine the effectiveness of periodontal instrumentation and home care by the patient. 2..Cementum,dfjafcin, and^aleulus are removed during root planing. 3. Tactile sensitivity refers to the ability to distinguish degrees of roughness and smoothness on the tooth surface.

Bone consists of: • two-thirds organic matter and one-third inorganic matrix • one-third organic matter and two-thirds inorganic matrix • one-half organic matter and one-half inorganic matrix • two-thirds inorganic matter and one-third organic matrix 117 骨骼包括： •三分之二的有机物和三分之一的无机基质 •三分之一有机物和三分之二的无机基质 •半有机物和半无机基质 •三分之二无机物和三分之一有机基质 117

• two-thirds inorganic matter and one-third organic matrix The alveolar process is the portion of the maxilla and mandible that forms and supports the tooth sockets (alveoli). It forms when the tooth erupts to provide the osseous attachment to the forming PDL; it disappears gradually after the tooth is lost. The alvolar process consists of the following: • An external plate of cortical bone formed by haversian bone and compacted bone lamellae. • The inner socket wall of thin, compact bone called the alveolar bone proper is seen as the lamina dura in radiographs. Histologically, it contains a series of openings (cribriform plate) through which neurovascular bundles link the PDL with the central component of the alveolar bone, the cancellous bone. • Cancellous trabeculae, located between the two compact layers, acts as supporting alveolar bone. The interdental septum consists of cancellous supporting bone enclosed within a compact border. In addition, the bones of the jaw include thebasal bone, which is the portion of the jaw located apically but unrelated to the teeth. Most of the facial and lingual portions of the sockets are formed by compact bone alone; cancellous bone surrounds the lamina dura in apical, apicolingual, and interradicular areas. Osteoblasts, the cells that produce the organic matrix of bone, are differentiated from pluripotent follicle cells. Alveolar bone is formed during fetal growth by intramembranous ossification and consists of a calcified matrix with osteocytes enclosed within spaces called lacunae. Bone consists of two-thirds inorganic matter and one-third organic matrix. The inorganic matrix is composed principally of the minerals calcium and phosphate, along with hydroxyl, carbonate, citrate, and trace amounts of other ions, such as sodium, magnesium^ and fluoride. The mineral salts are in the form of hydroxyapatite crystals and constitute approximately two thirds of the bone structure. The organic matrix consists mainly of collagen type I (90%), with small amounts of noncollagenous proteins such as osteocalcin, osteonectin, bone morphogenetic protein, phosphoproteins, and proteoglycans.

When sharpening, a wire edge is produced: • only when using a coarse artificial stone • when using a mounted ruby stone only • when no oil is used for lubrication of the stone • when the last stroke of t he stone is drawn away from the cutting edge 锐化时，线边缘产生： •仅当使用粗人造石时 •仅使用安装的红宝石时 •当石头不用润滑油时 •当石头的最后一个笔画从尖端处拉开时

• when the last stroke of t he stone is drawn away f r om the cutting edge Avoid formation of a "wire edge," which is produced when the direction of the sharpening stroke is away from, rather than into or toward, the cutting edge. When back-and-forth or up-and-down sharpening strokes are used, formation of a wire edge can be avoided by finishing with a down stroke toward the cutting edge. '^'J^^iU)MipgllllWflllWW™r~^^ The cutting edge of an instrument is formed by the angular junction of two surfaces of its blade. The cutting edges of a curette, for example, are formed where the face of the blade meets the lat-eral surfaces. When the instrument is sharp, this junction is a fine line running the length of the cut-ting edge. As the instrument is used, metal is worn away at the cutting edge, and the junction of the face and lateral surface becomes rounded or dulled. Thus, the cutting edge becomes a rounded sur-face rather than an acute angle. Sharpening stones can be categorized by their method of use: • Mounted rotary stones: these stones are mounted on a metal mandrel and used in a motor-driven handpiece. They may be cylindrical, conical, or disc-shaped. These stones are generally not recommended for routine use because they (1) are difficult to control precisely, (2) tend to wear down the instrument quickly, and (3) can generate considerable frictional heat, which may affect the temper of the instrument. • Unmounted stones: come in a variety of sizes and shapes. Unmounted stones may be used in two ways: the instrument may be stabilized and held stationary while the stone is drawn across it, or the stone may be stabilized and held stationary while the instrument is drawn across it. 1. The optimal internal angle between the face of the Wade and the lateral surface of Notes a universal curette and a Gracey curette is 70° to 80°. fSg$*i>*** 2. An instrument whose cutting edge is 90° or more will slip over calculus deposits and requires heavy lateral pressure to remove calculus deposits. 3. The best grasp to use when holding an instrument to be sharpened is the palm grasp.