Dentoalveolar

Question 1

Which of the following factors would be most important in deciding to remove a 2 mm fractured root tip of a maxillary molar?
(A) Close proximity of the root tip to the floor of the maxillary sinus
(B) Patient’s age less than 50
(C) Operator skill and experience
(D) Presence of periapical pathology

Answer 1

D

Question 2

Which of the following conditions is most likely to be associated with an asymptomatic erupted mandibular third molar in a young adult?
(A) Resorption of the distal root of the adjacent tooth
(B) Dental caries
(C) Localized periodontitis
(D) Dentigerous cysts

Answer 2

C

Question 3

Which of the following is an indication to perform a sulcular incision instead of a scalloped mucogingival junction incision when performing periapical surgery on a maxillary incisor?
(A) Presence of a short root
(B) Preserving anterior gingival esthetics
(C) Avoidance of releasing incisions
(D) Eliminate the need for suturing

Answer 3

A

Question 4

Which of the following factors is associated with a favorable outcome when surgical uprighting second molars?
(A) Uprighting involving an arc of rotation of greater than 90 degrees
(B) Incomplete vertical growth of the mandible
(C) The need to correct the bucco-lingual position of the tooth
(D) Second molar root formation is 2/3 complete

Answer 4

D

Question 5

he best technique for performance of a partial odontectomy (coronectomy) is to remove tooth structure:
(A) to a level approximately 3 mm above the level of the inferior alveolar canal and healing by secondary intention.
(B) so that the remaining roots are at least 3 mm below the crestal bone followed by healing by secondary intention.
(C) so that the remaining roots are at least 3 mm below the crestal bone followed by watertight primary closure.
(D) to a level approximately 3 mm above the level of the inferior alveolar canal followed by watertight primary closure.

Answer 5

C

Question 6

The best time to provide intravenous preoperative antibiotic therapy prior to removal of impacted third molars associated with pericoronal infection is:
(A) immediately prior to surgery.
(B) 0.5–2 hours prior to surgery.
(C) 3–4 hours prior to surgery.
(D) 6 hours prior to surgery.

Answer 6

B

Question 7

The best approach for surgical exposure of an impacted tooth for orthodontic bracketing is:
(A) complete exposure of the CEJ.
(B) partial exposure of the crown and avoiding exposure of the CEJ.
(C) complete exposure of the CEJ and 1 mm of surrounding alveolar bone.
(D) exposure of the crown until the greatest diameter of the crown is revealed regardless of
the CEJ.

Answer 7

B

Question 8

Which radiographic finding is most highly associated with inferior alveolar nerve exposure during surgical removal of mandibular third molars?
(A) Darkening of the third molar tooth root
(B) Narrowing of the third molar tooth root
(C) Deflection of the third molar roots
(D) A bifid inferior alveolar canal

Answer 8

A

Question 9

While attempting to extract impacted tooth #16, the tooth is suddenly displaced and is no longer visible or palpable. The patient now has limited mandibular opening. What is the most likely position of tooth #16?
(A) In the maxillary sinus
(B) In the buccal space
(C) In the body of the zygoma
(D) In the infratemporal space

Answer 9

D

Question 10

Patients with a history of oral bisphosphonate usage presenting with asymptomatic exposed bone should:
(A) have the non-vital bone surgically removed.
(B) be observed.
(C) start long term intravenous antibiotics.
(D) undergo hyperbaric oxygen therapy immediately.

Answer 10

B

Question 11

Which of the following factors would be most important in deciding to remove a 2 mm fractured root tip of a maxillary molar?
(A) Close proximity of the root tip to the floor of the maxillary sinus
(B) Patient’s age less than 50
(C) Operator skill and experience
(D) Presence of periapical pathology

Answer 11

D

Question 12

Which of the following conditions is most likely to be associated with an asymptomatic erupted mandibular third molar in a young adult?
(A) Resorption of the distal root of the adjacent tooth
(B) Dental caries
(C) Localized periodontitis
(D) Dentigerous cysts

Answer 12

C

Question 13

Which of the following is an indication to perform a sulcular incision instead of a scalloped mucogingival junction incision when performing periapical surgery on a maxillary incisor?
(A) Presence of a short root
(B) Preserving anterior gingival esthetics
(C) Avoidance of releasing incisions
(D) Eliminate the need for suturing

Answer 13

A

Question 14

Which of the following factors is associated with a favorable outcome when surgical uprighting second molars?
(A) Uprighting involving an arc of rotation of greater than 90 degrees
(B) Incomplete vertical growth of the mandible
(C) The need to correct the bucco-lingual position of the tooth
(D) Second molar root formation is 2/3 complete

Answer 14

D

Question 15

The best technique for performance of a partial odontectomy (coronectomy) is to remove tooth structure:
(A) to a level approximately 3 mm above the level of the inferior alveolar canal and healing by secondary intention.
(B) so that the remaining roots are at least 3 mm below the crestal bone followed by healing by secondary intention.
(C) so that the remaining roots are at least 3 mm below the crestal bone followed by watertight primary closure.
(D) to a level approximately 3 mm above the level of the inferior alveolar canal followed by watertight primary closure.

Answer 15

C

Question 16

The best time to provide intravenous preoperative antibiotic therapy prior to removal of impacted third molars associated with pericoronal infection is:
(A) immediately prior to surgery.
(B) 0.5–2 hours prior to surgery.
(C) 3–4 hours prior to surgery.
(D) 6 hours prior to surgery.

Answer 16

B

Question 17

The best approach for surgical exposure of an impacted tooth for orthodontic bracketing is:
(A) complete exposure of the CEJ.
(B) partial exposure of the crown and avoiding exposure of the CEJ.
(C) complete exposure of the CEJ and 1 mm of surrounding alveolar bone.
(D) exposure of the crown until the greatest diameter of the crown is revealed regardless of
the CEJ.

Answer 17

B

Question 18

Which radiographic finding is most highly associated with inferior alveolar nerve exposure during surgical removal of mandibular third molars?
(A) Darkening of the third molar tooth root
(B) Narrowing of the third molar tooth root
(C) Deflection of the third molar roots
(D) A bifid inferior alveolar canal

Answer 18

A

Question 19

Patients with a history of oral bisphosphonate usage presenting with asymptomatic exposed bone should:
(A) have the non-vital bone surgically removed.
(B) be observed.
(C) start long term intravenous antibiotics.
(D) undergo hyperbaric oxygen therapy immediately.

Answer 19

B

Question 20

When a primary tooth is traumatically intruded one should:
A. extract the tooth.
B. observe for 12 months and extract if it should not re-erupt.
C. splint the tooth 2-3 weeks.
D. observe for 4-8 weeks and extract if it should not re-erupt.

Answer 20

ANSWER: D
RATIONALE:
Immediate extraction does not give the tooth any chance for survival. If splinted in the intruded position, the tooth is condemned to a malposition. If splinted in the proper position, the expanded alveolus would not permit intimate root contact between the surrounding alveolus and periodontal ligament remnants on the root and therefore preclude survival. Observation for a year indicates that the tooth is ankylosed. Observation for 4-8 weeks and then extraction if no re-eruption is observed is the most appropriate answer.
REFERENCE:
Fonseca, RJ. Oral & Maxillofacial Surgery 2000. p.69

Question 21

When used in mandibular third molar extraction sockets, oxidized methylcellulose has been associated with transient changes in mandibular nerve function due to:
A. mechanical irritation of the nerve
B. irritation caused by metabolic breakdown products
C. acidic pH in the extracellular fluid surrounding the nerve
D. direct giant cell nerve injury

Answer 21

ANSWER: C
RATIONALE:
When metabolized, oxidized methylcellulose imparts a surrounding fluid pH of 2.8. Although direct mechanical trauma may always be a cause of neural dysfunction, the acid pH of the oxidized methylcellulose breakdown environment may be the most likely factor of neural dysfunction when used in the mandibular third molar extraction socket.
REFERENCE:
Conrad SM: Neurosensory disturbances as a result of chemical injury to the inferior alveolar nerve. OMS Clin N Amer 13:256, 2001
Loescher AR, Robinson PP: The effect of surgical medicaments on peripheral nerve function. Br J Oral Maxillofac Surg 36:330-2, 1998

Question 22

The most likely explanation for the greater extent of edentulous bone resorption seen in the mandible compared to the maxilla once teeth are lost is:
A. diminished blood flow through the inferior alveolar canal
B. greater muscle attachments to the mandible
C. increase mandibular osteoclastic activity
D. greater mandibular bone density

Answer 22

ANSWER: A
RATIONALE:
Though the pathogenesis of bone loss in the maxilla and mandible is obviously influenced by metabolic, traumatic, and infectious processes; the mandible is more susceptible due to its vascular supply. Bone density and osteoclastic activity are secondary issues and muscle attachments alone are not implicated in bone loss.
REFERENCE:
Fonseca, RJ, Oral and Maxillofacial Surgery Vol 7, Reconstruction and Implant Surgery, WB Saunders 2000

Question 23

When performing a z-plasty to remove a prominent labial frenum the secondary incisions are made at an angle approximately 60 degrees to allow the main limb to be rotated:
A. 33 degrees
B. 45 degrees
C. 60 degrees
D. 90 degrees

Answer 23

ANSWER: D
RATIONALE:
A z-plasty is designed to rotate the frenum or scar 90 degrees. Secondary incisions made at other angles may not allow as great a rotation of the main limb (in this case, the main frenum incision) as those made at 60 degrees tothe main limb.
REFERENCE:
Fonseca, RJ, Oral and Maxillofacial Surgery Vol 7, Reconstruction and Implant Surgery, WB Saunders 2000

Question 24

Which of the following is not an indication for the extraction of impacted third molars?
A. To prevent incisal crowding
B. To prevent caries and root resorption of the 2nd molar
C. To prevent a unanticipated split during orthognathic surgery
D. To allow distalization of teeth for orthodontic treatment

Answer 24

ANSWER: A RATIONALE:
There are several indications for the extraction of impacted third molars, depending on the position and soft tissue envelope; Root resorption, caries, and demineralization of the 2nd
molar are indications for 3rd molar removal. The presence of impacted 3rd molars during a bilateral sagittal split osteotomy may increase the likelihood of an unfavorable split and therefore may be removed six months prior to planned osteotomy. If uprighting or distalization
of the 2nd molar is required, the 3rd molar should be removed to prevent caries and root
resorption. No evidence exists that shows removal of impacted 3rd molars will prevent incisor crowding.
REFERENCE:
Fonseca, RJ, Oral and Maxillofacial Surgery Vol 7, Reconstruction and Implant Surgery, WB Saunders 2000

Question 25

The best technique for managemnt of an unerupted labially positioned maxillary canine lying high in the alveolus in a normally developing 14 year-old female is: A. an apically repositioned flap with bracketing and orthodontic tooth advancement B. exposure via a full thickness mucosal incision at the level of the impaction C. a full thickness flap, orthodontic bracketing, flap replacement and orthodontic tooth advancement under flap D. full thickness apically repositioned flap to allow passive eruption

Answer 25

ANSWER: C RATIONALE: A full thickness flap allows for maintenance of the attached gingiva. A mucosal incision at the level of the impaction would prevent the attached gingiva from moving with the tooth and an apically repositioned flap may not reliably expose the canine crown. In addition, an apically repositioned flap may not allow adequate exposure to remove bone and bond an orthodontic appliance. REFERENCE: Fonseca, RJ, Oral and Maxillofacial Surgery Vol 7, Reconstruction and Implant Surgery, WB Saunders 2000

Question 26

A vertical releasing incision for surgical exposure is planned during dentoalveolar surgery. Which of the following statements best describes the design of the anterior margin? A. It should end at the mesiobuccal line angle of the tooth B. It should cross the prominence of the canine tooth C. The extension should divide the interproximal papilla D. The incision should directly cross the facial aspect of the tooth

Answer 26

ANSWER: A RATIONALE: Releasing incisions aid in providing visualization and surgical exposure. A vertical releasing incision should cross the free gingival margin at the line angle of the tooth and should not be directly on the facial aspect of the tooth nor directly in the papilla. The incision is not a straight vertical incision but rather oblique, to allow the base of the flap to be broader than the free gingival margin. It should not cross bony prominences, such as the canine eminence. This would increase the likelihood of tension in the suture line, thus, possible wound dehiscence. Incisions that cross the free margin of the facial aspect of the tooth do not heal well because of tension and can result in a periodontal defect of the attached gingiva. Incisions that cross the gingival papillae damage the papillae and may result in localized periodontal problems. REFERENCE: Peterson, Ellis, Hupp, Tucker, Contemporary Oral and Maxillofacial Surgery, 4th Edition, Mosby 2003: 158-9

Question 27

As compared to submucous vestibuloplasty, secondary epithelialization vestibuloplasty should be performed when the patient: A. does not have existing dentures B. has an associated epulis fissuratum C. has phenytoin hyperplasia D. is young, with a better healing potential

Answer 27

ANSWER: B RATIONALE: Vestibuloplasty by submucous resection or secondary epithelialization may be indicated when a maxillary denture is unstable due to high muscle attachments with good underlying bone height and contour. both submucous vestibuloplasty and secondary epitheliazation require the same extent of supraperiosteal soft tissue dissection. However, submucous vestibuloplasty avoid the often painful healing associated with healing by secondary epithelialization. In some instances, horizontal epithelial incision is necessary, such as to remove an epulis fissuratum or when superior repositioning of the incision is necessary (when a shallow vestibular depth would cause inward vermillion rolling with a submucous vestibuloplasty technique.) Phenytoin hyperplasia, age, and existing dentures do not aid in the choice of vestibuloplasty technique. REFERENCE: Fonseca RJ, Davis WH. Reconstructive Preprosthetic Oral and Maxillofacial Surgery. 2nd Edition, Philadelphia, PA: WB Saunders; 1995; 789

Question 28

Which of the following is considered an advantage of mineral trioxide aggregate (MTA) over amalgam in periradicular surgery: A. more positive seal B. promotes electrochemical reaction C. no danger of contamination by moisture D. less expensive than amalgam

Answer 28

ANSWER: A RATIONALE: When compared to amalgam, MTA as a root end filling material has demonstrated more positive seal, desirable hydrophilic behavior, no electrochemical reaction, no corrosive properties, and no tattooing. Moisture control continues to be a concern in all retrograde materials and the cost of MTA is greater than that of conventional amalgam. REFERENCE: Fink, JB, “ Predicting the success and failure of surgical endodontic treatment” OMS Clinics, May 2002, p.162

Question 29

When treatment planning implants in children, it is recommended to place the implants after growth cessation. This is best evaluated by: A. serial cephalometric radiographs taken at 6 months B. chronologic age C. skeletal body height D. hand-wrist films evaluating epipheseal fusion

Answer 29

ANSWER: A RATIONALE: Chronological age and skeletal body height are poor indicators of growth completion. Skeletal age is better but, growth of facial bones lags slightly behind growth of long bones. Serial cephalometric radiographs provide the most accurate determination of facial growth completion. If no growth can be seen in 1 year it can be assumed that growth has ceased. Hand wrist films are a good indicator when compared to standardized films. REFERENCE: Kearns G, Implants in Children, OMS Knowledge Update Vol 3, p.67-81

Question 30

Which of the following is the most reliable radiologic predictor of possible inferior alveolar nerve injury during third molar surgery? A. Diversion of the inferior alveolar canal B. Deflection of third molar roots C. Narrowing of third molar roots D. Bifurcation of the root apex

Answer 30

ANSWER: A RATIONALE: While a variety of radiologic signs have been suggested to be associated with an increase in the risk of injury to the alveolar nerve during third molar removal, only three have been positively associated with an increased incidence of neurosensory deficit. They include diversion of the inferior alveolar canal, darkening of the root and interruption of the white line. None of the other choices listed have been associated with an increased risk. REFERENCE: Rood and Shehab, British Journal of Oral and Maxillofacial Surgery, 1990, Vol. 28, pp 20-25.

Question 31

``` Which of the following suture material is the slowest to be resorbed? A. Polyglactin 9/10 (Vicryl) B. Polyglycolic acid (Dexon) C. Surgical gut – chromic D. Polydioxanone (PDS II) ```

Answer 31

ANSWER: D RATIONALE: Vicryl and Dexon are both resorbed within 60 and 90 days by esterhydrolysis. While the rate of resorption of chromic gut is patient dependent, it is uniformly resorbed more rapidly(via enzymatic proteolysis) than the other materials listed. PDS II is only minimally absorbed until the90th day with continued resorption by ester hydrolysis not complete until 18-30 months. REFERENCE: Jenkins, Brandt, and Dembo, “Suture Principles in Dentoalveolar Surgery”, Oral and Maxillofacial Surgery Clinics of North America, Advanced Topics in Dentoalveolar Surgery, May 2002, pp 213-229.

Question 32

ll of the following reasons support removal of at least 3 mm of root during endodontic root surgery (apicoectomy) except: A. removal of lateral canals B. allows favorable placement of the soft tissue incision C. allows access for removal of associated pathologic tissue D. ease of placement of a retrofill restoration

Answer 32

ANSWER: B RATIONALE: The resection of 3 mm or more of the apex allows a larger surface for the retrograde preparation. Because the greatest number of lateral canals is located near the apex, resection of 3 mm or more also removes many of these difficult to seal canals, increasing the chance for success. Removal of apical root structure allows access to excise periapical pathology. The location and design of the soft tissue incision is determined by other factors. REFERENCE: Fink, J.B., “Predicting the Success and Failure of Surgical Endodontic Treatment”, Oral and Maxillofacial Surgery Clinics of North America, Vol. 14, No. 2, 2002, pp153-165.

Question 33

``` What diameter restorative table would require the most apical placement when inserting an implant to support a single maxillary central incisor restoration? A. 3.25 mm B. 4.1 mm C. 4.3 mm D. 5.0 mm ```

Answer 33

ANSWER: A RATIONALE: Narrow diameter restorative tables require more interocclusal space to allow the emergence profile necessary to develop proper physiologic contours in the final restoration. Therefore, the narrower the diameter of the restorative table, the deeper the implant would have to be placed. REFERENCE: Rotter, B.E., “Emergence Profile Considerations for Implant Surgery”, Oral and Maxillofacial Surgery Clinics of North America, Vol. 8, No. 3, August, 1996, pp 413

Question 34

``` All the following are associated with a significant increase in complications after the removal of asymptomatic impacted third molars except: A. age of the patient B. use of prophylactic antibiotics C. experience of the surgeon D. position of the tooth ```

Answer 34

ANSWER: B RATIONALE: Studies document an increase in the incidence and severity of complications associated with increasing patient age, degree and position of the impaction, and the experience of the operating surgeon. While recent studies suggest that in certain sub groups, prophylactic antibiotics may improve quality of life related measures during recovery, there is no evidence they decrease the rate of infection. REFERENCE: Chiapasco, deCicco, and Marrone, “Side Effects and Complications Associated with Third Molar Surgery”, Oral Surgery, Oral Medicine, Oral Pathology, Vol. 76, No. 5, October, 1993, pp 412- 420. Sisk, Hammer, Sheldon, Joy, “Complications Following the Removal of Impacted Third Molars”, Oral and Maxillofacial Surgery Clinics of North America, Vol. 44, pp 855-859, 1986. Sekhar, Narayanan, and Baig, “Role of Antimicrobials in Third Molar Surgery: A Prospective, Double-Blind Randomized, Placebo Controlled Clinical Study”, British Journal of Oral and Maxillofacial Surgery, Vol. 39, pp 134-137, 2001. Zeitler, D., “Prophylactic Antibiotics for Third Molar Surgery: A Dissenting Opinion”, Journal of Oral and Maxillofacial Surgery, Vol. 53, No. 60, pp 61-64, 1995,

Question 35

Which statement is not an indication for a labial vestibuloplasty, with floor-of-mouth lowering and split thickness skin graft? A. High muscle attachment of floor-of-mouth such that the denture is displaced when speaking B. Inadequate vestibular depth, with high buccinator attachment C. Lack of sufficient keratinized tissue covering the denture bearing areas of the mandibular ridge D. Atrophic mandible with less than 10 mm of mandibular bone height

Answer 35

ANSWER: D RATIONALE: The generally recognized minimum mandibular bone height for satisfactory denture bearing after a labiobuccal vestibuloplasty, lowering of the floor of the mouth and periosteal coverage by application of a split thickness skin graft is 15 mm. Proper contour of the alveolar ridge and keratinized tissue surface over this ridge is desirable. The split thickness skin graft adheres to denuded periosteum and provides a firm, resilient covering similar to keratinized gingiva. REFERENCE: Peterson, LJ Contemporary Oral and Maxillofacial Surgery, 3rd Edition, Mosby, 1998

Question 36

Which statement is not true regarding pericoronitis of a mandibular 3rd molar? A. The condition results from debris and bacterial contamination around the crown of a partially impacted tooth B. The infection is caused by normal oral flora C. Infection arises if host defenses become compromised and cannot maintain the delicate balance with the bacterial flora D. Antibiotics are indicated to decrease bacterial load

Answer 36

ANSWER: D RATIONALE: Antibiotics are a key aspect in localizing an infection and limiting its spread to adjacent tissue organs, areas, and spaces. Pericoronal infections that are localized to the immediate enveloping tissues and give no evidence of spread to adjacent tissue planes may require local debridement and definitive treatment consisting of removal of the erupting tooth and/or pericoronal tissues. REFERENCE: Peterson, LJ Contemporary Oral and Maxillofacial Surgery, 3rd Edition, Mosby, 1998

Question 37

Which of the following statements describing alveolar osteitis is incorrect? A. Generally develops 3-5 days after surgery B. Is an inflammation of bone, not necessarily an infection C. Is characterized by lysis of the socket blood clot D. Requires vigorous bone scraping to stimulate new blood clot formation

Answer 37

ANSWER: D RATIONALE: Alveolar osteitis is essentially an inflammation of the bony socket from a recently extracted tooth. Treatment consists of gentle debridement of the socket and placement of a suitable obdundant until the area becomes asymptomatic. Usually no local anesthesia is required. REFERENCE: Peterson, LJ Contemporary Oral and Maxillofacial Surgery, 3rd Edition, Mosby, 1998

Question 38

Management of oral-antral communications may require all of the following for closure except: A. tissue flap mobilization with water-tight closure B. stripping of all the sinus mucosa C. antibiotics and decongestants D. Metallic foil, membrane, or bone grafts

Answer 38

ANSWER: B RATIONALE: An established oral-antral communication may require several surgical aspects to close the defect successfully. Cardinal principles include (1) no active infection of the maxillary sinus and (2) adequate drainage of secretions into the nasal cavity. Stripping of all of the sinus mucosa is usually not indicated and can result in regeneration of a non-respiratory epithelium which may be detrimental to long term sinus health. Only the diseased mucosa requires removal. REFERENCE: Peterson, LJ Contemporary Oral and Maxillofacial Surgery, 3rd Edition, Mosby, 1998

Question 39

When performing a floor-of-the-mouth lowering procedure, it is necessary to: A. perform a subperiosteal dissection B. cover the denuded region with a soft tissue graft C. avoid altering muscle attachments in patients diagnosed with retrolingual sleep apnea D. detach all muscle attachments at the genial tubercle

Answer 39

ANSWER: C RATIONALE: Patients with suspected or diagnosed obstructive sleep apnea should not have muscle attachments altered in floor-of -mouth lowering procedures because this may worsen or create obstruction. Supraperiosteal dissections are performed and the incision margin is sutured to the periosteum at the depth of the vestibule. It is not necessary to place a soft tissue graft over the denuded periosteum as this may be allowed to secondarily epithelialize. The genioglossus muscle attachments at the genial tubercle may be partially removed to increase the lingual sulcus, but approximately 1⁄2 of the genioglossus attatchment should remain intact to ensure proper tongue function. REFERENCE: Fonseca RJ Oral and Maxillofacial Surgery Vol. 7 p. 49WB Saunders2000

Question 40

When performing maxillary sinus lifting and possible simultaneous implant placement which of the following is the primary determinate of an acceptable recipient site for implant placement? A. 2 mm of vertical bone height on panorex radiograph B. 3 mm of vertical bone height on panorex radiograph C. primary implant stability at the time of placement D. elevation of the sinus membrane without perforation

Answer 40

ANSWER: C RATIONALE: Vertical bone height may be a consideration in the treatment planning phase of simultaneous sinus lifting and implant placement. In general 4 mm of vertical bone height will provide a situation that may allow for simultaneous placement however, the true determinate is primary implant stability. REFERENCE: OMS Knowledge Update Volume 1 Part 1 IMP p. 47-53

Question 41

``` When performing a vestibuloplasty with split thickness skin graft what is the ideal thickness of the donor skin graft? A. 0.012 to 0.015 inches B. 0.012 to 0.015 mm C. 0.030 to 0.035 inches D. 0.030 to 0.35 mm ```

Answer 41

ANSWER: A RATIONALE: When harvesting a split thickness skin graft the ideal thickness should be 0.012 to 0.015 inches. This allows the graft to contain both epidermis and the superficial dermis. Allowing early revascularization. REFERENCE: Fonseca, RJ, Davis WH, Reconstructive Preprosthetic Oral and Maxillofacial Surgery, WB Saunders, Philadelphia, 1995, p.752

Question 42

``` A patient radiographically exhibits mesioangular mandibular third molar impaction and a lack of bone along the distal surface of the adjacent second molar. Up to which age would you expect predictable bony regeneration along the distal second molar surface after third molar removal without the use of adjunctive tissue regeneration techniques? ? A. Up to 14 years B. 18 years C. 25 years D. 30 years ```

Answer 42

ANSWER: C RATIONALE: The likelihood of persistence of a pre-existing preoperative periodontal defect posterior to the second molar in the postoperative period increase with the age of the patient. Kugelberg found that patients younger than 25 years had a zero to minimal increase in the depth of the periodontal attachments. In patients that are 25 years of age or less one can predict bony regeneration of such defects. REFERENCE: OMS Knowledge Update Vol 1, Part 2, DAV Kugelberg, CF. Periodontal healing two and four years after impacted lower third molar surgery. Int J Oral Maxillofac Surg. 1990; 19:341-345

Question 43

Closure of a well established, oral-antral fistula greater than 5 mm in diameter may be most predictably accomplished by: A. Long term antibiotic and decongestant therapy B. Periodic observation for at least six months C. Rotation of a palatal island flap D. Bone graft augmentation to the fistula.

Answer 43

ANSWER: C RATIONALE: Communication between the maxillary sinus and oral cavity is an uncommon complication and occurs mostly on the sites of the maxillary first molar, followed by the second molar, third molar, and second premolar. Although smaller defects of less than 5 mm in diameter may close spontaneously, larger communications generally require surgical closure. Palatal flaps are based on the greater palatine artery and can be mobilized and rotated to close oral-antral fistulae. The most practical palatal flap design is a rotational flap that has a wedge removed near its base to facilitate rotation. When mobilized, the palatal tissue serves as an excellent source of tissue to close an oral-antral fistula, especially in an edentulous areas because there is no vestibular distortion. REFERENCE: Principles of Oral & Maxillofacila Surgery, Larry Peterson, AT Indresano, R Marciani, S Roser; 1997, Vol 2, pages 1002-1004. Lee JJ, Kok SH, Chang HH, Yang PJ, Hahn LJ, Kuo YS. Repair of oroantral communications in the third molar regio by random palatal flap. International Journal of Oral and Maxillofacial Surgery. 31 (6): 677-80, 2002 Dec. Kraut RA, Smith RV. Team approach for closure of oroantral and oronasal fistulae. Atlas of the Oral and Maxillofacial Surgery Clinics of North America 8 (1): 55-75, 2000 Mar.

Question 44

Bacteria commonly recovered from cases of pericoronitis include: A. Fusobacterium, Streptococcus milleri, Peptostreptococcus. B. Streptococcus pyogenes, Prevotella capillosis, Kingella kingal C. Staphylococcus Xylosis, Prevotella bivia. D. Streptococcus Pyogenes, Staphylococcus aureus, Bacteroides fragilis.

Answer 44

ANSWER: A RATIONALE: Most samples recover 10-15 different isolates. The predominant facultative anaerobic bacteria include Streptococcus milleri. Predominate obligatory anaerobes include spirochetes and fusobacterium. Pathogens well known for causing supprative infections such as Staphylococcus aureus and Streptococcus pyogenes were only rarely found. REFERENCE: Peltroche-Llacsahuanga, et al “Investigation of Infectious Organisms Causing Pericoronitis of the Mandibular Third Molar” JOMS 58:611-616 2000

Question 45

``` The bacteria surrounding a failing implant differs from the microbiology associated with the healthy implant. Which of the following best describes the bacterial population around a failing implant? A. Aerobic gram-positive cocci. B. Anaerobic gram-positive cocci. C. Aerobic gram-negative rods. D. Anaerobic gram-negative rods. ```

Answer 45

ANSWER: D RATIONALE: Large numbers of gram-negative anaerobic rods (A. actinomycetemcomitans, P. gingivalis, P. intermedia) tend to be found around the failing implant. The endotoxins produced by gram- negative bacteria have the capability to adhere to the implant surface and cause inflammation, which results in bone loss. Momsell in 2000 identified bacteria as the primary etiologic agent in peri-implantitis. Healthy implants were found to be colonized with gram positive cocci. REFERENCE: Triplett, R.G. et al “Management of Peri-implantitis” Oral and Maxillofacial Surgery Clinics of North America 15 (2003) 129-138

Question 46

one augmentation at the site of osseointegrated implants protected by an expanded polytetraflouroethylene (e-PTFE) membrane does not require: A. immobility of the membrane. B. trimming of the membrane away from adjacent teeth. C. close adaptation of the membrane to the exposed implant. D. extension of the membrane at least 3 mm beyond the defect margins.

Answer 46

ANSWER: C RATIONALE: Initial stabilization of the membrane is important for wound healing. Normally, material stability can be achieved by placing the edge of the membrane subperiosteally. In order for any defect to be treated successfully, it is essential to create and maintain a space under the material into which cells with osteogenic capacity can migrate, so creation of a space between the membrane and the implant is desirable to allow osteogenesis between the implant and membrane. To cover the defect adequately, the membrane should extend at least 3 mms beyond the margin of the defect. This extension should prevent soft tissue in-growth as well as stabilizing the thrombus beneath the membrane. REFERENCE: Dahlin C, Sennerby L. Bone Augmentation os Osseointegrated Implants Induced by a Membrane Technique. OMFS Clinics of N. Am. Vol. 3, No. 4, Nov. 1991, p. 941

Question 47

Which of the following statements about the risk of bleeding in a patient who is to under go an extraction is false? A. Cancer chemotherapeutics may cause thrombocytopenia. B. Alcohol abuse may cause changes in prothrombin time and partial thromboplastin time. C. Broad-spectrum antibiotic therapy may affect factors II, VII, IX, and X as well as prothrombin time. D. Partial thromboplastin time is the most appropriate test for acquired coagulopathies.

Answer 47

ANSWER: D RATIONALE: The best screening test for aquired coagulopathies is the prothrombin time (PT) or the International Normalized Ratio (INR). To have a reasonably good chance of achieving hemostasis by local measures, the patient's PT should be within 1.5 times the control time and the INR below 2.0. Myelosuppression, as manifested by leukopenia, thrombocytopenia, and anemia, are common sequelae of cancer chemotherapy. Within 2 weeks of the beginning chemotherapy, the white blood cell count falls to an extremely low level. Thrombocytopenia can be marked, and spontaneous oral cavity bleeding may occur. Recovery from myelosuppression is usually complete 3 weeks from cessation of chemotherapy. Alcohol abuse may cause liver cirrhosis and thus decrease production of the liver dependent coagulation factors, thus obtaining a PT and PTT may be prudent in this patient population. Broad spectrum antibiotics may cause a change in the intestinal flora, which may decrease vitamin K production. Vitamin K is necessary for the liver to produce adequate quantities of coagulation factors II, VII, IX, and X. If the patient has a history of prolonged broad spectrum antibiotic therapy, the surgeon should be suspicious of decreased hemostasis. REFERENCE: Peterson et al. Contemporary Oral and Maxillofacial Surgery. Pp. 278-82, 1988.

Question 48

The minimum distance that should be maintained between endosseous dental implants is how many millimeters? A. 1 B. 3 C. 5 D. 7

Answer 48

ANSWER: B RATIONALE: To maximize the chance for success, there must be adequate bone width to allow1 mm of bone on the lingual aspect and 0.5mm on the facial aspect of the implant. There should also be adequate space between the implants. The minimal distance between implants varies slightly among implant systems, but is generally accepted as 3mms. This minimal space is necessary to ensure bone viability between implants and to allow adequate oral hygiene once the restorative dentistry is complete. REFERENCE: Contemporary Oral and Maxillofacial Surgery. Peterson, Ellis, Hupp and Tucker. P. 390

Question 49

Which of the following complications most commonly occurs after tooth autotransplantation? A. Failure to develop periodontal anchorage B. Acute periapical abscess C. Alveolar bone resorption D. Root resorption

Answer 49

ANSWER: D RATIONALE: In the cited reference, 114 out of 416 cases of tooth autotransplantation failed. Seventy of these cases failed, and were lacking a tooth at initial follow-up. Of the remaining teeth, 58 failed secondary to internal and external root resorption, 8 failed to achieve adequate bony stability, and the final 4 developed periapical abscesses. REFERENCE: Pogrel MA: Evaluation of over 400 autogenous tooth transplants. J oral maxiollofac Surg 45:205, 1987.

Question 50

``` The most commonly impacted supernumerary tooth is the: A. mandibular premolar. B. maxillary fourth molar. C. maxillary canine. D. mesiodens. ```

Answer 50

ANSWER: D RATIONALE: The most common impacted supernumerary tooth is the mesiodens. In descending order this is followed by the supernumerary maxillary incisor, fourth molar, and mandibular premolar. REFERENCE: Kaban LB: Pediatric oral and maxiollofacial surgery, chapter 7, p. 105; Saunders1990.

Question 51

``` Following one year of function, a healthy endosseous implant is expected to incur subsequent bone loss of how many millimeters per year? A. 0.1 B. 0.4 C. 0.8 D. 1.0 ```

Answer 51

ANSWER: A RATIONALE: As described in the reference, in the first year of implant function, a loss of 0.8mm to 1.0 mm of bone can be expected without any subsequent clinical complications. REFERENCE: Misch C., Contemporary Implant Dentistry, 2nd Edition, p.24, Mosby 1999.

Question 52

``` Which of the following has the greatest modulus of elasticity? A. Bone B. Titanium C. Hydroxyapatite D. Gold Alloy ```

Answer 52

ANSWER: A RATIONALE: The modulus of elasticity is the ability of a material to flex or bend under stress. In the mandible the muscles of mastication cause bone to flex on opening and closing. An implant system should have the ability to flex also when the mandible is functioning. Hydroxyapatite is brittle and has a low modulus of elasticity. Titanium flexes but is still relatively rigid. The gold alloy used in the transmandibular implant (TMI) is the most flexible of these three choices but none have as great an ability to bend under applied stress as does the mandible. REFERENCE: Fonseca, RJ and Davis, WH. Reconstructive Preprosthetic Oral and Maxillofacial Surgery 2nd edition, WB Saunders 1995

Question 53

A 60 year old women presents one week after a transmandibular implant to the lower jaw. A postoperative panoramic radiograph reveals a non-displaced fracture between the right lateral and medial post. The appropriate treatment would be to: A. Remove the transmandibular implant B. Place distal transmandibular extension plates to stabilize the fracture C. Remove the baseplate D. Recommend a soft diet and weekly observation

Answer 53

ANSWER: D RATIONALE: The transmandibular implant provides a rigid box frame in the anterior aspect of the mandible. Any nondisplaced fracture that occurs within the box frame will be stabilized by the implant. In this case the fracture occurred between the lateral and medial post, which is within the box frame. There would be no reason to remove the implant and this option would require additional stabilization. Removing the base plate would disrupt the box frame and could cause the fracture to displace. If the fracture occurred proximal to the lateral post then a distal extension plate would be indicated. The correct choice would be to observe the patient weekly and place them on a soft diet. REFERENCE: Fonseca, RJ and Davis, WH. Reconstructive Preprosthetic Oral and Maxillofacial Surgery 2nd edition, WB Saunders 1995