Endodontics

Examination of a radiograph reveals evidence of internal resorption in the middle third of the root of a maxillary central incisor. The patient has no discomfort and the pulp responds vitally to testing. The dentist should recommend: A. reducing the occlusion. B. performing a pulpotomy. C. performing endodontic treatment. D. doing nothing at this time and re-evaluating in six months.

Correct Answer: C Incisors have the highest incidence of internal resorption. Although there have been many suggested causes, there is no definite etiology. A nonsurgical endodontic approach is the treatment of choice if the resorptive defect has not perforated the canal wall and the standard trial of endodontic requirements (sanitization, debridement and obturation) can be met. If the three basic endodontic tenets can be met but there is a perforation of the canal wall to the epithelial attachment, a calcium hydroxide technique should be used. An apicoectomy is the surgical removal of the root tip and does not provide access to the middle third of the root. Simply reducing the occlusion or adopting a wait and see attitude are not indicated when dealing with internal resorption. When there is extensive tooth destruction or uncontrolled bleeding, extraction may be necessary.

Radiographs reveal a maxillary incisor with internal resorption which has not perforated the root surface. If the patient has no symptoms and the examination reveals a healthy unblemished crown, the procedure of choice is to: A. extract the tooth. B. observe the tooth. C. initiate conservative endodontic therapy. D. initiate surgical endodontic therapy.

Correct Answer: C Internal resorption is RARE in permanent teeth. External resorption is often misdiagnosed as internal resorption. Conceptual treatment of internal resorption is easy; however, the size and location of the resorptive defect may be technically quite difficult to treat. The addition of MTA as an endodontic material has revitalized and improved the outcome of this treatment.

Elevated body temperature and generalized malaise may be associated with: 1. acute pulpitis. 2. acute alveolar abscess. 3. acute apical periodontitis. 4. chronic apical periodontitis (granuloma). A. 1 and 2 B. 1 and 3 C. 2 and 3 D. 2 and 4 E. 3 and 4

Correct Answer: C Periapical lesions of pulpal origin are inflammatory responses to irritants from within the root canal system. Confusingly, these lesions manifest a variety of signs and symptoms. Signs and symptoms may range from an asymptomatic response to slight sensitivity to chewing, feeling of tooth elongation, intense pain, swelling, high fever or malaise. Pulpitis, whether reversible or not, infers that the irritating factors are at this point still contained within the tooth and thus there is no periapical inflammatory response. Acute apical periodontitis and acute alveolar abscess both indicate inflammation in the apical region resulting from the egress of necrotic or bacterial toxins. Both can cause the systemic response of elevated body temperature and malaise. The response to an acute pulpitis, being contained within the tooth, will not include a fever or malaise. Chronic apical periodontitis or granuloma is a long-standing or smoldering condition of the periapical area, invariably a sequel to pulpal necrosis. The clinical features of chronic apical periodontitis are unremarkable and the patient experiences no significant pain, fever or malaise.

Which of the following statements regarding the Profile® rotary instrumentation is accurate? A. They are used at a range of 1500 to 2000 rpm. B. They are NiTi instruments manufactured in half size. C. They are offered in sizes that are ISO and ANSI standardized. D. They incorporate radial lands in the flute design.

Correct Answer: C Profile instruments are sized in the ISO and ANSI standard and are not offered in "half" sizes. Lightspeed® operates in the 1000 to 2000 rpm range whereas Profile® is used at 150 to 300 rpm. Lightspeed®, Profile® and Quantic all have radial lands in their flute design.

A patient presents with severe spontaneous pain of 36 hours duration from the maxillary right first molar. The tooth was restored three days ago with a large MOD restoration and a base. The tooth gives a positive response to the electric pulp tester and is not sensitive to heat. Based on this evidence, the most probable diagnosis would be: A. acute apical periodontitis. B. hyperocclusion C. irreversible pulpitis. D. reversible pulpitis.

Correct Answer: C Spontaneous pain is characteristic of irreversible pulpitis. Reversible pulpitis is asymptomatic unless provoked by an external stimulus. This also is true of hyperocclusion. Acute apical periodontitis could be considered if the tooth was exquisitely tender to percussion, but based on the findings presented, it would be ruled out.

The optimal healing for a horizontal root fracture consists of: A. connective tissue healing. B. granulation tissue healing. C. combination calcific and connective tissue healing. D. calcific healing.

Correct Answer: D Calcific healing is ideal and is dependent on expert and prompt intervention. Close proximation (with radiographic verification) of the segments, proper splinting (2-4 weeks) and treatment with a short time interval between injury and treatment are key. Although calcific healing is ideal, two other forms of healing are successful; 1. Healing with interproximal connective tissue; and 2. Healing with interproximal bone and connective tissue. Remarkably, the apical and coronal segments remain vital with prompt treatment.

A nine-year-old boy is seen two days after receiving a traumatic blow to the face. Examination reveals a fracture involving enamel and dentin. There is no response to electric pulp testing. The condition of the pulp is: A. nonvital. B. ischemic. C. hyperemic. D. currently indeterminable.

Correct Answer: D For decades controversy has surrounded the validity of thermal and electric pulp testing on traumatized teeth. Only generalized impressions may be gained from these tests subsequent to traumatic injury. In reality they are sensitivity tests to determine nerve function and do not indicate the presence or absence of blood circulation within the pulp. It is assumed that, subsequent to traumatic injury, the conduction capability of nerve endings and/or sensory receptors is sufficiently deranged to inhibit the nerve impulse from an electrical or thermal stimulus. Consequently, the traumatized tooth is vulnerable to false negative readings from these tests. Thermal and electrical pulp tests of teeth in the traumatized area should be done at the time of initial examination and carefully recorded to establish a baseline for comparison with subsequent tests in later months. The purpose of the tests is to establish a trend as to the physiologic status of the pulps of these teeth. Teeth that give a positive response at the initial examination cannot be assumed to be healthy because they may give a negative response at a later date. Teeth that yield a negative response cannot be assumed to have necrotic pulps, because they may give a positive response on subsequent testing. The transition from a negative to a positive response at a subsequent test may be considered a sign of a healthy pulp. The repetitious finding of positive responses may be taken as a sigh of healthy pulp. The transition from a positive to negative response may be taken as an indicator that the pulp is probably undergoing degeneration. The persistence of a negative response would suggest that the pulp has been irreparably damaged, but even this is not absolute.

Which of the following factors of internal anatomy is NOT important to attaining an optimal access opening for endodontic treatment? A. Position of the root canals B. Shape of the pulp chamber C. Intracoronal preparation D. Length of the roots

Correct Answer: D Ideal access is the key to quality endodontic results. Straight-line access to each canal is paramount to exceptional instrumentation. Therefore, development of the access opening must first address the shape of the pulp chamber which reveals the position of the root canals from the straight line access. Overpreparation of the access must be avoided to preserve coronal integrity for restoration. As the length of the roots is a vertical (depth) phenomenon, it is not integral to canal access.

The objectives of cleaning and shaping the root canal system are to: 1. obtain access to the canal. 2. remove tissue debris and bacteria. 3. prepare the canal for obturation. 4. determine working length. A. 1 and 2 B. 1 and 3 C. 1 and 4 D. 2 and 3 E. 2 and 4

Correct Answer: D Proper cleaning and shaping of the canal ensures not only that the pulp tissue, necrotic debris, microorganisms, and affected dentin must be removed from the treated tooth, but also that the canal walls must be prepared to receive a filling material that will seal the apical foramen.

The day following pulpal extirpation and extensive root canal instrumentation, the patient reports extreme discomfort. In addition to overinstrumentation, this may be related to: 1. caustic intracanal medication. 2. periapical inflammation. 3. incomplete removal of pulpal tissue. 4. forcing debris into the periapical tissue. A. 1 and 2 B. 2 and 3 C. 1, 3 and 4 D. All of the above

Correct Answer: D The most frequent cause of secondary apical periodontics is overinstrumentation, but the condition may also occur as a result of overmedication (too caustic or too much intracanal medicament) forcing debris into the periapical tissues. Incomplete removal of the pulpal tissue may also be a factor.

External root resorption may be attributed to which of the following? 1. Periapical inflammation 2. Excessive mechanical or occlusal forces 3. Impacted teeth 4. Tumors and cysts A. 1 and 2 B. 2 and 3 C. 1, 2 and 3 D. 2, 3 and 4 E. All of the above

Correct Answer: E Periapical inflammation is associated with apical external resorption, as is orthodontic movement or excessive mechanical or occlusal force. Pressure from an impacted tooth may cause external root resorption at the contact area of the two teeth. Clinically, the resorption ceases when the impacted tooth is removed. If the resorption is not severe, repair may be expected. Finally, tumors and cysts have been directly linked to external root resorption.

Postoperative instructions to a patient that has undergone tooth resection therapy include all the following except one. Which is the exception? A. Heat applied to the area intermittently for the first 24 hours. B. Pain medication taken as prescribed beginning as soon as possible after surgery. C. Cold applied to the area intermittently for the first 24 hours. D. The patient contacting the dentist if any unexpected swelling occurs.

Answer: A

Making an endodontic diagnosis can be difficult because there are several pain disorders that can refer pain to the teeth. Which of the following groups of non-odontogenic disorders is most likely to cause tooth pain? A. Neurovascular or headache pain B. Neuropathic pain C. Psychogenic pain D. Myofascial pain

Correct Answer: (D) Myofascial pain Neurovascular pain has qualities similar to pulpal pain. Neuropathic pain actually arises from abnormalities in the neural structures themselves. Psychogenic pain is known to be precipitated by severe psychological stress. Although any deep somatic tissue type pain in the head and neck has the propensity to evidence central excitatory effects therefore cause referral of pain to the teeth. Pains of muscular origin appear to be the most common.

Although diagnosis is a science, it is an imperfect science, and sometimes a detailed, definitive diagnosis is difficult or impossible. Importantly, significant pulpal or periapical pathosis is frequently without marked symptoms at present or in the past. A. Both statements are TRUE. B. Both statements are FALSE. C. The first statement is TRUE; the second is FALSE. D. The first statement is FALSE; the second is TRUE.

Correct Answer: A A clinician must be methodical, disciplined and knowledgeable in both the art and science of endodontics for proper diagnosis. To rely solely on one piece of evidence is folly. Such a monothematic approach often results in improper diagnosis. Wisdom must be consulted in diagnosis. Sometimes deferral of treatment is wise. The literature and the courts are littered with knee-jerk treatment resulting in unresolved symptoms of patients.

Gaining knowledge of anatomy from textbooks is the most important and most useful method of learning. Common and frequent variations must be memorized for each tooth. A. Both statements are TRUE. B. Both statements are FALSE. C. The first statement is TRUE; the second is FALSE. D. The first statement is FALSE; the second is TRUE.

Correct Answer: A As much as an intimate knowledge of dental anatomy is necessary for proper restorative execution, intimate and thorough knowledge of internal pulpal anatomy is needed to access, negotiate and obturate the root canal system. Radiographic evidence is an impression but is often limited by dimensional and resolution limitations. Three dimensional images of sufficient detail to fully elucidate the complete root canal system currently limit our treatment modalities. Fortunately, research and thermoplastic obturation aid in overcoming, to some degree, these difficulties.

A patient presents to your office complaining of sharp severe pain in a right maxillary central incisor. The patient states that the tooth has been sensitive since the insertion of a composite resin placed three month previously. For the past week, the tooth has been sensitive to heat; cold liquids tend to relieve the pain. Early last evening, the tooth began to throb constantly without provocation. Radiographic examination reveals no abnormal changes in bone density. What would be a possible clinical classification of the problem? A. Symptomatic irreversible pulpitis B. Symptomatic irreversible pulpitis C. Acute apical abscess D. Hyperplastic pulpitis

Correct Answer: A As the pulp degenerates it renders a state of non-healing partial necrosis. Intermittent or spontaneous pain occurs; heightened painful response to thermal stimuli (especially cold) occurs. Typically, radiographic detection is difficult or impossible due to no or subtle changes in appearance. Clinical signs and symptoms solidify the diagnosis & clarify the treatment course.

Prior to endodontic therapy, adequate isolation requires that caries, defective restorations, and restorations with leaky margins be removed. This preparation ensures an aseptic field of operation, allows for tooth restorability, and permits temporization between visits. A. Both statements are TRUE. B. Both statements are FALSE. C. The first statement is TRUE; the second is FALSE. D. The first statement is FALSE; the second is TRUE.

Correct Answer: A Asepsis of the root canal system is essential. Confirmation of tooth restorability prior to initiation of root canal therapy prevents embarrassing excuses to patients after the completion of the root canal therapy that a tooth is nonrestorable and must be extracted. Leaky restorations allow contamination of an otherwise aseptic endodontic field compromising success.

The distance between the floor of the cavity preparation and the pulp greatly influences the pulpal response. A remaining dentin thickness of 2 mm would protect the pulp from the effects of most restorative procedures, providing all other operative precautions were observed. A. Both statements are TRUE. B. Both statements are FALSE. C. The first statement is TRUE; the second is FALSE. D. The first statement is FALSE; the second is TRUE.

Correct Answer: A Dentin permeability increases exponentially with increasing cavity depth, as both diameter and density of dentinal tubules increase as the cavity deepens.

Most treatment failures related to deficiencies in obturation are long-term failures. A low volume of irritant or slow release or irritant into periapical tissues produces damage that is not apparent in the short term. A. Both statements are TRUE. B. Both statements are FALSE. C. The first statement is TRUE; the second is FALSE. D. The first statement is FALSE; the second is TRUE.

Correct Answer: A Each phase of endodontic therapy is dependent on the prior phase. Correct diagnosis leads to proper access which leads to proper instrumentation which leads to proper obturation which leads to proper restoration. Deficiencies in any step compromise the subsequent steps or outcome. The thorough and seasoned clinician recognizes this and pays attention to all details. Long term follow up is the true test of success.

Which of the following actions is most likely to cause breakage of an endodontic instrument? A. Reaming with a small diameter file B. Filing with a small diameter file C. Reaming with a large diameter file D. Filing with a large diameter file

Correct Answer: A Instrument separation may occur with a Gate Glidden drill, piezo drill, lentulo-spiral, thermomechanical gutta-percha compacter or the tips of hand instruments, files or reamers. Usually separated instruments are files or reamers. The most common causes are: improper use; limitations in physical properties; inadequate access; root canal anatomy; and manufacturing defects. Of these, improper use is very common. There are at least eight types of improper use.

Usually the first symptom that best describes a cracked tooth is: A. sharp pain on release of biting pressure. B. sensitivity to percussion. C. hypersensitivity to vitality tests. D. a periodontal defect.

Correct Answer: A Radiographically, vertical tooth fractures are rarely detectable in their early stages as the fractured segments most often do not separate. Radiographic evidence is not detectable until much later in the sequence of events. The most reliable and earliest aid in diagnosis is in the dental history. The patient often states, "the tooth only hurts when I bite a certain way," or "it only started hurting after I accidentally bit down on a cherry pit." Vertical root fracture may also be implicated by a recently placed post and core, cast intracoronal restoration or a recently placed restoration that keeps "falling out."

Endodontic cases requiring localized periodontal surgery are distinguished by caries or fracture below the free gingival margin but above the crestal bone. Various gingivectomy techniques are contraindicated due to inadequate zone of attached gingiva. A. Both statements are TRUE. B. Both statements are FALSE. C. The first statement is TRUE; the second is FALSE. D. The first statement is FALSE; the second is TRUE.

Correct Answer: A Rubber dam clamp placement on sound dentin should be aimed at and likewise the margins of the final restoration (i.e. crown). Occasionally the crestal bone and overlying gingiva maybe so compromised that simple corrective procedures may not suffice. (**The review critique in the AGD book is written just as you see it here—it's really poorly written—so sorry. Also, the upcoming Profile answer/explanation is not well written, either.—Jen)

Postoperative instructions to a patient that has undergone tooth resection therapy include all of the following except one. Which is the exception? (Ed. #17) A. Heat applied to the area intermittently for the first 24 hours. B. Pain medication taken as prescribed beginning as soon as possible after surgery. C. Cold applied to the area intermittently for the first 24 hours. D. The patient contacting the dentist if any unexpected swelling occurs.

Correct Answer: A There is no instance where heat is administered intermittently after any surgical procedure due to the increase in blood supply and associated bleeding.

Apexification is most often used for the endodontic management of a non-vital permanent tooth having a wide-open blunderbuss apex. The primary purpose of apexification is to stimulate the formation of calcified tissue at the root apex. A. Both statements are TRUE. B. Both statements are FALSE. C. The first statement is TRUE; the second is FALSE. D. The first statement is FALSE; the second is TRUE.

Correct Answer: A Until recently, the most widely accepted technique has been cleaning and filling the canal with a temporary paste to stimulate the formation of calcified tissue at the apex. The temporary paste is later removed after radiographic evidence of apical closure has been obtained and a permanent filling of gutta percha is placed in the canal.

Agents used within the pulp chamber to bleach endodontically-treated teeth include: 1. Superoxol (30% hydrogen peroxide). 2. sodium hypochlorite. 3. sodium perborate. 4. hydrochloric acid. A. 1 and 2 B. 1 and 3 C. 2 and 3 D. 2 and 4 E. 3 and 4

Correct Answer: B The agent that has been most commonly used within the pulp chamber to bleach endodontically treated teeth is a 30% solution of hydrogen peroxide (Superoxol). Superoxol is "steamed" into the dentinal tubules. This procedure may be replaced, or followed by sealing a paste of Superoxol and powdered sodium perborate into the pulp chamber for 3 to 7 days. Superoxol is a powerful oxidizing agent, which acts directly on the tooth stains. Since sodium perborate in a liquid vehicle also releases oxygen, it has been used in combination with the 30% hydrogen peroxide to bleach endodontically treated teeth. Sodium hypochlorite is commonly used in surface disinfection and endodontic procedures. Sodium hypochlorite and hydrochloric acid are not used to bleach endodontically treated teeth.

A tooth with an irreversible pulpitis has been opened, extirpated and irrigated, but the remaining tissue continues to bleed. All of the following procedures would be used to treat this condition except one. Which is the exception? A. Let the bleeding continue unimpeded until it subsides. B. Leave the coronal access open to avoid pressure buildup. C. Remove as much of the pulp tissue as feasible for emergency treatment. D. Place a medicated pellet and close the coronal opening with a temporary filling.

Correct Answer: B The important point here is to remove all of the pulpal tissue. Teeth with irreversible pulpitis should not be left open because bacterial contamination of the canal will occur.

First aid for the avulsed tooth consists of which five steps in chronological order? A. Seek dental care immediately, rinse tooth in warm running water, do not scrub tooth, replace tooth in socket gently, hold tooth in position. B. Rinse tooth in cold running water, do not scrub tooth, replace tooth in socket gently, hold tooth in position, seek dental care immediately. C. Rinse tooth in cold running water, replace tooth in socket gently, apply ice to tooth, hold in position, seek dental care immediately. D. Seek milk or other calcium rich medium, replace in socket gently, hold tooth in position, notify parents, seek emergency care at local hospital.

Correct Answer: B The keys to successful reimplantation are time and control of contaminants. For the laymen to be successful, actions mush be easily accomplished in minimal time. While dentally, calcium cold media may be preferable, it may not be readily available. Emergency departments at local hospitals are ill equipped for dental emergencies particularly when time is of the essence. The skilled dental practitioner may argue the details, but for the layman "in the heat of battle," these stages are easily doable.

Dental dams are considered standard of care for endodontic therapy. The dental dam is available in many thicknesses. The thickness of the dental dam recommended for endodontic therapy is: A. light B. medium C. heavy D. extra heavy

Correct Answer: B To perform endodontics without a dental dam is legally indefensible. All dental schools teach the use and placement of dental dams. Light weight dental dams tear too easily during application. Heavy weight dental dams are too bulky. Thus, a medium weight dental dam is preferred for most endodontic procedures.

The most common cause of root canal failure is related to the: (Ed. #17) A. incomplete obturation of the canal system. B. incomplete instrumentation of the canal system. C. inability to locate accessory canals. D. use of volatile intracanal medicaments.

Correct Answer: B Treatment failures are most often due to insufficient cleaning and obturation of the pulpal spaces. Even in well treated teeth, canal irregularities, the dentinal tubules, deltas or isthmus areas may trap microorganisms and create a failure.

Apexification technique is the treatment of choice for a permanent tooth with a wide open apex when: A. there is a large carious lesion. B. the tooth is pulpless or periapical disease is evident. C. there is a fracture of the clinical crown exposing the pulp for less than 24 hours. D. there is a mechanical exposure.

Correct Answer: B When a tooth with an incompletely formed apex becomes pulpless or periapical disease has developed, apexification is the preferred treatment. Although highly successful, apexification should be the treatment of last resort in the tooth with an incompletely formed root. Attention should be focused on the maintenance of pulpal vitality within these teeth so that as much root length and dentin formation as possible can occur within the root. Indirect pulp therapy, vital pulp capping and pulpotomy techniques have proved to be successful. These treatments should be the treatment of choice if the possibility of success exists with them.

A patient complaining of maxillary pain that is more intense when lying down and is relieved when in an upright position is probably suffering from: A. an abscess. B. maxillary sinusitis. C. a cyst. D. trigeminal neuralgia.

Correct Answer: B When pain is perceived in a patient in maxillary teeth near the sinus area and pulpal/periradicular pathosis is absent, sinus/nasal mucosal disease should be suspected. Throbbing or increased pain sensation can occur when the head is placed lower than the heart. Dental local anesthetic blocks will not abate sinus/nasal mucosal pain.

The splinting time for an avulsed tooth without a major bony fracture should be: (Ed. #17) A. 4-6 days. B. 1-2 weeks. C. 3-5 weeks. D. 6-8 weeks.

Correct Answer: B A splint should be removed in 7-10 days unless a major bone fracture occurs.

An 18-year-old male patient presents within 30 minutes following a blow to the mouth during a football scrimmage. Intraoral examination reveals that both maxillary central incisors are slightly mobile. A periapical radiograph reveals horizontal root fracture on both teeth located in the middle one-third of the root. There are no communications between the fracture and gingival sulcus. What should you do? A. Do nothing, as this will heal on its own. B. Institute root canal therapy to prevent root resorption later. C. Rigidly splint the teeth to immobilize them. D. Rigidly splint the teeth for two to four months followed by root canal therapy.

Correct Answer: C Degree of dislocation and mobility of coronal fragments are extremely important. The greater the fragments are separated, the poorer the prognosis. A successful outcome correlates closely to quick treatment, close proximity of root segments and rigid splinting for two to four months.

Which is the most frequent cause of endodontic failure? A. Instrumentation failure B. Immunocompromised patients C. Incomplete obturation D. Fractured roots

Correct Answer: C In endodontic therapy, incomplete obturation may allow new microorganisms to re-enter and re-infect the canal space. This can lead to a new round of chronic or even acute periapical periodontitis.

Virtually all flap designs for apical surgery are combinations of vertical and horizontal incisions. Variations in the number and position of vertical relaxing incisions account for different designs (ie., triangular, rectangular, trapezoidal, semilunar). A. Both statements are TRUE. B. Both statements are FALSE. C. The first statement is TRUE; the second is FALSE. D. The first statement is FALSE; the second is TRUE.

Correct Answer: (A) Both statements are TRUE. Combinations of vertical and horizontal incisions are used to achieve various flap designs. The number of vertical releasing incisions therefore governs the major variation in design.

The primary nociceptors of the pulp that respond to inflammation are the slow conducting high threshold C-fibers. All of the following are associated with C-fibers except one. Which is the exception? A. C-fibers do not respond to normal or non-pathologic dentinal stimulation. B. C-fibers typically do not conduct pain associated with tissue damage. C. C-fibers respond in a threshold manner that can be termed "all or nothing." D. Pulpal pain is mediated by C-fibers and is dull, aching or throbbing in nature.

Correct Answer: (B) C-fibers typically do not conduct pain associated with tissue damage. C-fibers typically conduct pain that is associated with tissue damage.

All of the following may be indicative of an acute periapical abscess except one. Which is the exception? A. Absence of intact lamina dura B. Pain on percussion or tooth contact C. Normal thermal testing D. Presence of facial cellulitis

Correct Answer: (C) Normal thermal testing This condition is defined as an inflammatory reaction to pulp infection and necrosis characterized by rapid onset, spontaneous pain, tenderness of the tooth to pressure, pus formation, and swelling of associated tissues

All of the following are elements in promoting root resorption except one. Which is the exception? A. Macrophage B. Osteoclasts C. Osteoprotegerin (OPG) D. Interleukin-1

Correct Answer: (C) Osteoprotegerin (OPG) Osteoprotegerin act as an inhibitor for resorptive cells. Osteoclasts are stimulated by macrophage and interleukin-1.

Which of the following materials most consistently prevents micro-leakage of the coronal aspect of obturated root canals? A. Cavit B. SuperEBA C. Resin-modified glass ionomer D. IRM

Correct Answer: (C) Resin-modified glass ionomer Leakage studies indicate that the coronal seal can be enhanced by the application of supplemental restorative materials over the canal orifice as soon as feasible. One study demonstrated that placement of Cavit or SuperEBA cement-decreased bacterial leakage by 85% and 65% respectfully when compared with unsealed controls, which all leaked by 45 days. A resin modified glass ionomer cement was placed approximately 1 mm thick over the floor of the pulp chamber and polymerized with a curing light. This technique showed no leakage after 60 days.

Which of the following aids are most helpful in diagnosing irreversible pulpitis? A. A good medical history B. Electric vitality tests C. Thermal stimulation D. Examining for mobility

Correct Answer: (C) Thermal stimulation Cold testing is the primary pulp testing used by clinicians. Frozen carbon dioxide has been found to be useful in eliciting a positive response if vital tissue is present within the tooth. This is superior to electric testing. Mobility does not indicate pulpal vitality. Heat testing is most useful when the chief complaint is intense pain upon contact with any hot liquid or food. Medical history has no bearing on pulpal vitality.

A patient presents with severe spontaneous pain of 36 hour duration from the maxillary right first molar. The tooth was restored three days ago with a large, deep MOD amalgam. The tooth gives a positive response to the electric pulp tester, is not sensitive to heat, and is not overly tender to percussion. Based on this evidence, the most probable diagnosis would be: A. acute apical periodontitis. B. hyper occlusion. C. irreversible pulpitis. D. reversible pulpitis.

Correct Answer: (C) irreversible pulpitis. A symptomatic irreversible pulpitis is often an emergency condition that requires immediate treatment. These teeth exhibit intermittent or spontaneous pain, whereby exposure to extreme temperature, especially cold, will elicit intense and prolonged episodes of pain, even after the source of the stimulus is removed.

Regarding replantation of an avulsed tooth, which clinical presentation has the poorest prognosis? A. Partially to completely closed apex with less than one hour extraoral dry time B. Open apex and less than one hour extraoral dry time C. Partially to completely closed apex and more than one hour extraoral dry time D. Open apex and more than one hour extraoral dry time

Correct Answer: (D) Open apex and more than one hour extraoral dry time Preparation of the root depends on the maturity of the tooth (open vs closed apex) and on the average time of the tooth before it was placed in a storage medium. A dry time of 60 minutes is considered the point where survival of root periodontal ligaments cells is unlikely. A closed apex has a greater chance of treatment success than the open apex.

If a patient presents with severe dental pain triggered by cold, which of the following is LEAST likely to be associated with the offending tooth? A. Pain upon percussion. B. Periapical radiolucency C. Radiographic evidence of possible pulp exposure D. Response to electric pulp testing.

Correct Answer: B A necrotic tooth does not cause radiographic changes at the apex until the periapical pathosis has destroyed bony trabeculae at their junction with the cortical plate. Thus a great deal of bone destruction may occur before any radiographic signs are evident. The state of pulpal health or pulpal necrosis cannot be determined radiographically, but any of the following findings should arouse suspicion of degenerative pulp changes; deep carious lesions, deep and extensive restorations, pulp caps, pulpotomies, pulp stones, extensive canal calcification, root fractures, thickened periodontal ligament, and periodontal disease that is radiographically evident. Radiographs alone are of little assistance in diagnosing symptomatic irreversible pulpitis. The percussion test may reveal whether there is any inflammation around the periodontal ligament. The clinician should remember that the percussion test does not give any indication of the health or integrity of the pulp tissue, it indicates only whether there is inflammation around the periodontal ligament. The electric pulp tester is designed to stimulate a response by electric excitation of the neural elements within the pulp. Not only does it help the clinician in determining pulp vitality, but with thermal and periodontal test it can also aid in differentiating among radiographic signs for pulpal, periodontal, or nonodontogenic causes. The electric pulp test is one of the last tests to be performed. This test merely corroborates what other diagnostic tests have indicated.

27. The incidence of a third root, usually distolingual in mandibular second molars, is approximately: A. 1.0%. B. 2.2%. C. 8.3%. D. 17.3%.

Correct Answer: B Although rarely occurring, additional roots in any tooth must be taken into account when performing endodontic therapy. A missed canal within an additional root must be located and treated. Failure to search out and treat additional roots on teeth lends to embarrassing and potentially litigious confrontations with patients. Their endodontic failure may be 100% failure to that patient.

Treatment of choice of chronic periapical pathosis includes: A. pulpotomy. B. nonsurgical root canal treatment. C. incision and drainage. D. drainage through the tooth. E. surgical root canal treatment.

Correct Answer: B Chronic periapical pathosis is most often due to incompletely instrumented or poorly obturated root canal spaces. Often an additional canal is the culprit. It is often more successful and more conservative to revisit the original non-surgical mode of root canal therapy via retreatment.

A patient presents with sharp, shooting pain in a tooth that has a deep amalgam restoration. The pain occurs spontaneously every hour or two, lasting about five minutes. The tooth responds to vitality tests, is sensitive to cold, and shows no radiographic periapical changes. These symptoms are suggestive of: A. pulpal necrosis. B. irreversible pulpitis. C. reversible pulpitis. D. hyperplastic pulpitis.

Correct Answer: B Irreversible pulpitis may be symptomatic or asymptomatic. With the former, pain may be spontaneous and prolonged even after the source of the pain is removed, especially with cold stimuli. There are minimal to no radiographic changes and deep restorations are often found.

What is the initial treatment of choice when a patient calls with moderate to severe pain two hours following the obturation of a root canal? A. Remove the root canal filling material B. Prescribe analgesics C. Apply moist heat and use warm water rinses. D. Use an ice pack and cold water rinses.

Correct Answer: B Most post operative pain is a result of inflammation. The vast majority of patients will respond favorably with proper endodontic treatment and OTC nonsteroidal anti-inflammatory agents. It is rare that a patient does not respond favorably within 24-48 hours after appropriate endodontic therapy.

In cases of vital extirpation, endodontically treated teeth are much more comfortable to the patient if the root canal is filled: A. to the radiographic apex. B. to the anatomic apex. C. 1-2 mm short of the anatomic apex. D. 1-2 mm beyond the radiographic apex.

Correct Answer: B One visit obturation of vital pulps is acceptable in many instances because of the absence of bacterial contamination. The length of obturation is in theory generally agreed to be to the anatomical apex. The location of the anatomic apex and its clinical determination has been a source of much controversy and research. Further, the role of accessory canals in obturation is controversial.

A patient presents with an endodontically treated mandibular central incisor that is continuously tender to percussion. Which of the following is the most likely cause? A. Too large of a lingual opening B. An untreated canal C. Traumatic occlusion D. Exposed cementum

Correct Answer: B Over 40% of mandibular incisors have two canals. Commonly untreated, the untreated canal leads to post-treatment symptoms. A second canal to the lingual is often missed. Therefore, access should err to the lingual. This is a safe extension of the access opening as perforation in this direction is difficult.

A patient presents with radiographic evidence of root resorption. The location of the resorptive area is coincident with the pulp canal in the mid-root area. How can you distinguish whether this is internal or external resorption? 1. The margins of an internal resorptive defect are smooth and well defined. 2. If it is internal resorption only, radiographs exposed at differing horizontal angulations will show movement of the resorption in relation to the pulp. 3. External resorptive defects have smooth and well-defined borders. 4. External resorptive defects are usually asymmetrical. A. 1 and 2 B. 1 and 4 C. 2 and 3 D. 3 and 4

Correct Answer: B Radiographic comparison of internal and external resorption is a study in contrasts. Visually internal resorption is rounded and symmetric, will not shift off center when the angle of the radiographic beam changes, appears as an expansion to the canal or pulp chamber and the pulp chamber or canal appears as a ghost within the defect. External resorption is irregular, moth eaten or irregular in shape, the defect position in the tooth will move radiographically when the X-ray beam angle is changed, it appears to eat away the root structure; and there is acute delineation between the root structure and resorbing front.

The most common pathway for microbes and microbial products to reach the pulp is: A. apical extension of periodontal disease. B. directly through carious lesion. C. pulpal inflammation and anachoresis. D. from adjoining necrotic pulps and periapical lesions.

Correct Answer: B Research shows that caries is the most common cause of pulpal disease. Dentin sclerosis is the most common response to dentin caries which isolates and kills odontoblastic processes. In the process, a diffusion of soluble irritants and inflammatory stimuli invade the pulp causing inflammation.

A 20-year-old patient presents two weeks after sustaining a traumatic blow to a maxillary central incisor. The tooth is asymptomatic and gives a normal vital response to heat, cold and electric pulp testing. A radiograph shows a horizontal fracture on the apical third of the root with segments in close apposition. The tooth exhibits Class II mobility. The initial treatment is to: A. relieve occlusion and evaluate in one month. B. initiate endodontic therapy with calcium hydroxide in the coronal portion. C. relieve the occlusion and stabilize the tooth. D. perform root canal therapy and remove the root fragment.

Correct Answer: C The clinical decisions regarding treatment of the tooth with a fractured root become logical efforts to enhance the healing capacity of that root. In the mechanism of root repair and separation of the broken segments in the alveolar socket, hemorrhage from broken capillaries in the pulp and periodontal ligament flows into the fracture site and clots. This clot is gradually organized by fibroblasts into fibrous connective tissue. The fractured surfaces and dentin and cementum are gradually remodeled by surface resorption and apposition of calcific tissue. Depending on the amount of separation of the fragments, three alternative forms of repair may occur: 1. Calcific healing is possible when the fragments are in close apposition and there is little mobility of the parts. It is possible to get a calcific callus both externally on the root surface and internally on the root canal wall. 2. If the fragments are separated further, mobility is impeded and a fibrous attachment similar to a periodontal ligament may develop between the segments. 3. Finally, with severe dislocation of the segments, necrosis may occur, stimulating inflammation and granulation tissue formation in the fracture lines. Studies have shown that the majority of teeth with horizontal root fractures will maintain vitality of pulp tissues. Consequently, the ultimate goal of the clinician should be to attempt to gain reunion of the fragments by calcified callus formation. Preservation of the vitality of the pulp will certainly enhance the process. Therefore, the fracture should be reduced as soon as possible, the broken tooth firmly stabilized and the occlusion reduced. Endodontic therapy or treatment with calcium hydroxide are not the preferred initial treatment modalities.

A patient receiving 10mg of corticosteroids daily for the past seven months requires an apicoectomy. Antibiotic therapy should be instituted because: A. it will promote rapid healing. B. corticosteroid therapy will be discontinued and the patient requires protective therapy. C. the normal defensive responses of the body are depressed in a patient receiving corticosteroids. D. None of the above. Antibiotic therapy is not required for a patient receiving short-term corticosteroids.

Correct Answer: C The condition of a patient who is receiving corticosteroid therapy may be well controlled. However, this patient is susceptible to adrenal crisis when stressed as well as to the added risk of infection. Cortisone decreases the capacity of the organelles to release their enzymes. In normal situations these enzymes could be effective against invading microorganisms. Cortisone interferes with the intercellular destruction of microorganisms by neutrophils and also impairs the action of monocytes, decreasing macrophage activity. Wound healing is impaired during cortisone therapy affecting the fibroblasts and, therefore, the quantity and quality of collagen. The inhibitory actions of the glucocorticoids suppress immunologic and inflammatory responses and wound healing. Antibody inhibition is due to the functional inhibition of both B- and T-lymphocytes. When it becomes necessary to discontinue therapy of a high dose of steroids, it must be done in a gradual manner. Prior to stressful dental procedures, however, a temporary increase in dosage is often indicated.

A patient presents complaining of chronic low-grade pain in the mandibular left first molar. Adjusting the occlusion gives relief, but the pain returns in a week. The tooth has been endodontically treated and has a NARROW, 9 mm periodontal pocket on the mesial surface of the mesial root. The most probably diagnosis would be: A. incomplete apical seal of the root canal. B. bruxism. C. vertical fracture. D. periodontal abscess. E. external resorption.

Correct Answer: C The key factor here is the clinical finding of a narrow, 9 mm periodontal pocket. Percussion sensitivity correlates with the involvement of the PDL. A periodontal abscess would be associated with a more generalized loss of bone and external resorption should be seen radiographically. Bruxism should be evident by faceting on the occlusal surface and the pain more generalized. A lack of apical seal should be suggested radiographically and would be less significant compared to the vertical defect.

A 14-year-old male presents to your dental office. Dental imaging reveals a horizontal root fracture of both the maxillary central incisors in the middle third of the roots. The apices are closed. There is no evidence of displacement or mobility. Your treatment should be: A. perform immediate root canal therapy then observe. B. extirpate the pulps and fill the root canal spaces with calcium hydroxide paste. C. no treatment is indicated. Reevaluate on recall. D. treatment plan dental implants as the teeth are hopeless.

Correct Answer: C The key to this scenario is the fact that there is no mobility or displacement of the fractured fragments. The scenario is self-splinting. Pulpal vitality at this stage of the injury is suspect and no treatment is warranted. Unimpeded or interrupted healing by the body should be allowed to occur.

A patient presents with an onlay on tooth #20. The tooth is asymptomatic but the pulp is necrotic and a periapical radiograph reveals a well-defined unilocular radiolucency at the root apex. The most likely diagnosis would be: A. chronic pulpitis. B. acute apical periodontitis. C. chronic apical periodontitis. D. acute apical abscess.

Correct Answer: C The presence of a well-defined unilocular radiolucency places the lesion in the chronic category of apical periodontitis versus pain that one might see in an acute lesion.

Which of the following statements concerning the diagnosis of endodontic problems is true? (Ed. #17) A. Negative EPT readings are invalid. B. An acute periradicular abscess appears as a widening of the periodontal ligament. C. Ice testing indicates the degree of inflammation within the pulp. D. Condensing osteitis usually necessitates endodontic treatment.

Correct Answer: C Thermal testing with ice or refrigerant is the most accurate determinant of pulpal vitality.

For which clinical problems might hemisection or root amputation be useful? 1. Periodontally involved furcations 2. Mandibular molars with severe decay involving both roots 3. Teeth with deep decay localized on a single root 4. A molar is which one root is endodontically non-negotiable 5. A molar with fused roots. A. 1 and 3 B. 3 and 4 C. 1, 3 and 4 D. 2, 4 and 5 E. All of the above

Correct Answer: C When traditional endodontics and periodontics treatment prove insufficient to stabilize an affected tooth, hemisection or root amputation may be required if there is bone loss in the bifurcation or trifurcation area. A localized periodontal defect, inability to perform adequate root canal therapy, extensive caries on one or more of the roots, or an iatrogenic problem are other reasons to explore these treatment options. It is not possible to amputate one of two fused roots, nor is it practical to hemisect a tooth with sever decay affecting both roots.