Dentoalveolar Surgery Flashcards
- 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: 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
- 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: 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
- 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: 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
- 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: 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
- 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: 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
- 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: 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
- 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: 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
- 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: 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
- 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: 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
- 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: 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.
- 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: 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.
- Which of the following cardiac conditions is not indicated for antibiotic prophylaxis when removing a carious first molar?
A. Prosthetic cardiac valves
B. Hypertrophic cardiomyopathy
C. Mitral valve prolapse without regurgitation
D. A history of bacterial endocarditis
ANSWER: C
RATIONALE:
The American Heart Association recommends antibiotic premedication for patients with a variety of cardiac conditions known to have moderate to high risk of endocarditis. Among others, these include prosthetic cardiac valves, a history of bacterial endocarditis, and hypertrophic cardiomyopathy. While mitral valve prolapse with regurgitation should also be premedicated, MVP without regurgitation does not require pre-treatment with antibiotics.
REFERENCE:
Savage, M.G., “Antibiotic Prophylaxis and Dentoalveolar Surgery”, Oral and Maxillofacial Surgery Clinics of North America, Vol. 14, No. 2, 2002, pp 231-240.
- All 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: 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.
- 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: 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 413-429
