Dentoalveolar questions OMSITE

Question 1

Osteogenesis occurs with which of the following grafting materials? A. Allogeneic bone grafts B. Xenographic bone grafts C. Alloplastic bone grafts D. Autogenous bone grafts

Answer 1

Answer: D Rationale: Osteogenesis refers to the growth of bone from viable cells transferred within the graft. Autogenous bone is the only graft material available with osteogenic properties. Allogeneic bone grafts (allografts) are treated in bone banks in a variety of methods, resulting in different mineralized, freeze-dried, solvent-dehydrated, or demineralized states. Allografts such as demineralized freeze-dried bone and solvent-dehydrated mineralized bone have been advocated for use in extraction sites because of their osteoconductive nature and the characteristic that they will resorb and be replaced within a relatively short period of time. Xenografts are graft materials harvested from a species other than human, typically bovine, and are processed to remove the antigenicity by a variety of chemical and preparation techniques. The absence of proteins results in minimal immune response in vivo. Alloplasts include forms of calcium phosphate materialsóeither dense or porous hydroxylapatite, hard tissue replacement, and bioactive glass. These materials have proved useful for retaining alveolar bulk but can be slow to resorb because of their chemical characteristics. Recent advances in adding materials or changing the chemical characteristics of these materials, however, recently have been shown to provide maintenance of form and also allow for bone formation. Reference: Misch, CE, Contemporary Implant Dentistry 2nd edition, page 455, Mosby 1999. Block, MS, Treatment of the single tooth extraction site. Oral and Maxillofacial Surgery Clinics of North America, Volume 16, Issue 1, February 2004, Pages 41-63

Question 2

The phase in alveolar distraction osteogenesis for implant site development, which occurs at the end of distraction until the device is removed is known as the: A. latency period. B. distraction period. C. consolidation period. D. activation period.

Answer 2

Answer: C Rationale: The consolidation period follows active distraction and continues until device removal. The length of the consolidation period is influenced by the age of the patient, distance and time of distraction, and the amount of surgical trauma at the time of surgery. In cases of increased surgical trauma, recommendations are for increasing the time of the latency period and the consolidation period. The latency period is the time between device placement/osteotomy and activation of the distractor. The distraction period is the classic term for the time frame during which the distraction device is activated and the gap between the osteotomy segments is expanded. The activation period could also describe the distraction period, but is not classic terminology. Reference: Batal H, Cottrell D. Alveolar distraction osteogenesis for implant site development. Oral Maxillofacial Surg Clin N Am 16 (2004) p.94. Peterson, LJ, Ellis, E, Hupp, JR, Tucker, MR. Contemporary Oral and Maxillofacial Surgery 4th Edition, Mosby, St. Louis, 2003, p. 582-584.

Question 3

Following completion of alveolar distraction, the stabilizing device is maintained for: A. 2 - 4 weeks. B. 5 - 7 weeks. C. 8 - 12 weeks. D. 13 - 17 weeks.

Answer 3

Answer: C Rationale: The ability of the distractor to stabilize the newly formed bone within the distraction gap is key to the formation of a healthy regenerate. Unstable devices are associated with increased endochondral bone formation and delayed bone formation within the distraction gap. Stable devices lead to direct osteogenesis without intervening cartilage formation. Reference: Batal H, Cottrell D. Alveolar distraction osteogenesis for implant site development. Oral Maxillofacial Surg Clin N Am 16 (2004) p.93 - 94. Saulacić, N, MartÌn, M, Camacho, and GarcÌa, A Complications in Alveolar Distraction Osteogenesis: A Clinical Investigation Journal of Oral and Maxillofacial Surgery, Volume 65, Issue 2, February 2007, Pages 267- 274

Question 4

When performing alveolar ridge development using orthodontic forced eruption, what is the recommended amount of tooth movement per month? A. 1.0 - 2.0 mm B. 2.1 - 3.0 mm C. 3.1 - 4.0 mm D. 4.1 - 5.0 mm

Answer 4

Answer: A Rationale: The orthodontist needs to know what the clinician plans to gain by the forces applied to the tooth or teeth in the treatment area. Forces for crown lengthening would be rapid. By contrast, forced eruption for implant site development would be slower, approximately 1 to 2 mm per month. Caution should be taken to avoid moving the root too rapidly. In addition, the length of root in bone may affect the rate of movement and amount of applied force necessary. In a situation of severe bone loss, the remaining root in bone may be minimal (providing less resistance) and may move faster. Reference: Hinds K. Alveolar ridge development with forced eruption and distraction of retained natural dentition. Oral Maxillofacial Surg Clin N Am 16 (2004) p.76 - 78. Mantzikos T, Shamus I. Forced eruption and implant site development: an osteophysiologic response. Am J Orthod Dentofacial Orthop 1999; 115(5):583ñ91.

Question 5

When performing a ridge splitting technique to expand the edentulous ridge for insertion of an interpositional bone graft prior to implant placement, what is the preferred preoperative minimum ridge width? A. 1 mm B. 2 mm C. 3 mm D. 4 mm

Answer 5

Answer: C Rationale: The ridge splitting technique is used to expand the edentulous ridge for implant placement or insertion of an interpositional bone graft. This technique is only suitable for enhancing ridge width. There must be adequate available bone height for implant placement, and no vertical bone defect should be present. Although skilled surgeons may be able to expand very thin ridges, a minimum width of 3.0 mm is preferred. Splitting ridges narrower than this is technique sensitive and can result in bone fractures and resorption. Reference: Misch C. Implant site development using ridge splitting techniques. Oral Maxillofacial Surg Clin N Am (2004) p.65. Fonseca, et al. Oral and Maxillofacial Surgery: Reconstructive and Implant Surgery: (Vol 7). Pages 219-221.

Question 6

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. Diversion of the inferior alveolar canal

Answer 6

Answer: A Rationale: IAN exposure is associated with increased incidence of IAN injury1. The radiographic finding linked with the most relative risk is darkening of the third molar tooth root 2. All other answers are associated with IAN exposure, but to a lesser amount. Reference: Valmaseda-Castellon E, Berini-Aytes L, Gay-Escoda C. Inferior alveolar nerve damage after lower third molar surgical extraction: a prospective study of 1117 surgical extractions. Oral Surg Oral Med Oral Pathol Oral Radiol Endod. 2001; 92:377-383. Sedaghatfar M, August MA, Dodson TB. Panoramic radiographic findings as predictors of inferior alveolar nerve exposure following third molar extraction. J Oral Maxillofac Surg. 2005; 63:3-7.

Question 7

What is the frequency with which the lingual nerve runs superior to the lingual crest of the mandible? A. < 5% B. 10% C. 30% D. 50%

Answer 7

Answer: B Rationale: In a clinical study utilizing magnetic resonance imaging of the mandibles of normal human subjects, the lingual nerve was found to be on average 2.8mm inferior to the lingual crest and 2.5mm medial to the lingual plate. In 10% of the group, the lingual nerve was above the lingual crest and 25% were in direct contact to the lingual plate. Reference: Behnia H et al, An anatomic study of the lingual nerve in the third molar region.J Oral Maxillofacial Surg, 2000. 58:649. Miloro M et al, Assessment of the lingual nerve in the third molar region using magnetic resonance imaging. J Oral Maxillofacial Surg, 1997. 55:134.

Question 8

What is the most frequent postoperative complication of third molar extraction? A. Localized alveolar osteitis B. Subperiosteal abscess C. Inferior alveolar nerve injury D. Lingual nerve injury

Answer 8

Answer: A Rationale: In a prospective study involving 63 surgeons, 3,760 patients, and 8,333 third molars; it was found that the incidence of localized alveolar osteitis was 12% in mandibular molars. Other complication rates were: infection 1%, IAN injury 1.1-1.7%, Lingual nerve injury 0.3%. Reference: Haug, R, et al. The American Association of Oral and Maxillofacial Surgeons Age-Related Third Molar Study. JOMS 63:1106-1114, 2005 Dentoalveolar Surgery in Peterson’s Principles of Oral and Maxillofacial Surgery, Miloro, M. et al., Editors, Second Edition, BC Decker Inc, 2004, pp. 151.

Question 9

While attempting to extract an 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

Answer: D Rationale: Upper third molars can be displaced distally into the infratemporal space if excessive distal elevation is used without placement of retraction distal to the tooth. In this particular case, the new finding of restricted opening gives a clue that the tooth is not in the maxillary sinus, but most probably impinging on the coronoid process, and thus is in the infratemporal fossa. Reference: Dentoalveolar Surgery in Peterson’s Principles of Oral and Maxillofacial Surgery, Miloro, M. et al., Editors, Second Edition, BC Decker Inc, 2004, pp. 152. Fonseca, et al. Oral and Maxillofacial Surgery: Anesthesia/Dentoalveolar Surgery/Office Management. (Vol 1). W.B. Saunders Company. Philadelphia. 2000. p426-427.

Question 10

The posterior extension of an incision designed for removal of an impacted mandibular third molar is extended laterally because: A. this design places the incision in keratinized tissue. B. this design avoids injury to the buccal artery. C. this design avoids injury to the lingual nerve. D. this design reduces postoperative trismus.

Answer 10

Answer: C Rationale: The incision design for removal of impacted third molar flares laterally to avoid possible injury to the lingual nerve. The mandibular ramus flares laterally and the lingual nerve extends above the lingual crest 10% of the time. Reference: Ness GM, Peterson LJ. Impacted Teeth, p. 144. In Miloro M ed. Oral and Maxillofacial Surgery, vol. 1, BC Becker, 2004. Miloro M, Halkias LE, Slone HW, Chakeres DW. Assessment of the lingual nerve in the third molar region using magnetic resonance imaging. J Oral Maxillofac Surg 1997;52:134-7.

Question 11

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 11

Answer: B Rationale: The surgical exposure of an impacted tooth should be carried out conservatively so that only enough bone and soft tissue is removed to place on orthodontic bracket. Damaging effects to the periodontium have been shown to be more frequent with exposure of the CEJ. Reference: Zeitler DL. Management of Impacted Teeth other than Third Molars, pp.133-134. In Miloro M ed. Oral and Maxillofacial Surgery, Vol. 1, BC Becker, 2004. Kohavi D, Becker A, Silverman Y. Surgical exposure, orthodontic movement, and final tooth position as factors in periodontal breakdown of treated palatally impacted canines. Am J Orthod 1984; 85:72-77.

Question 12

Bleeding encountered during exploration for this displaced, previously impacted, maxillary third molar would most likely emanate from the: (picture of maxillary third molar in infra temporal fossa) A. pterygoid venous plexus. B. sphenopalatine artery. C. descending palatine artery. D. masseteric artery.

Answer 12

Answer: A Rationale: This scan depicts a tooth displaced into the infratemporal fossa. Maxillary third molars that are superiorly positioned may have only a thin layer of bone separating them from the infratemporal space. Venous bleeding from the pterygoid plexus of veins often makes visualization of the tooth difficult. Reference: Bouloux GF et al. Complications of Third Molar Surgery. Oral and Maxillofacial Surg Clin N Am 19 (2007), p. 122. American Board of Oral and Maxillofacial Surgery 86 2008 Oral and Maxillofacial Surgery Self Assessment Tool (OMSSAT) Pogrel M. Complications of Third Molar Surgery. Oral and Maxillofacial Surg Clin N Am 1990; 2:441.

Question 13

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 13

Answer: B Rationale: Prophylactic antibiotic therapy for asymptomatic impacted third molars in healthy patients is not indicated. For the compromised patient or one who is actively infected, antibiotic administration should be timed so that incision is performed at the peak systemic concentration. Reference: Mehrabi M, Allen JM, Roser SM.. Therapeutic Agents in Perioperative Third Molar Surgical Procedures. Oral Maxillofacial Surg Clin N Am 19(2007), p. 71. Woods RK, Dellinger EP. Current guidelines for antibiotic prophylaxis of surgical wounds. Am Fam Physician 1998; 57 (11):2731-40.

Question 14

When compared to areas grafted with palatal autografts, areas grafted with acellular dermal matrix allografts demonstrate which of the following qualities? A. Less graft shrinkage and greater amounts of keratinized tissue B. More graft shrinkage and greater amounts of keratinized tissue C. Less graft shrinkage and lesser amounts of keratinized tissue D. More graft shrinkage and lesser amounts of keratinized tissue

Answer 14

Answer: D Rationale: Acellular dermal matrix grafts act as a biologically compatible framework into which fibroblasts and epithelial cells can migrate and adhere, thus repopulating and incorporating the cells into the material. These migrating tissues replace the dermal matrix, causing increased graft shrinkage and ultimately resulting in lesser amounts of keratinized tissue at the recipient site. Reference: Yan JJ. Tsai AY. Wong MY. Hou LT. Int J Periodontics Restorative Dent. 2006 June; 26(3):287-92 McGuire MK. Nunn ME. Evaluation of the safety and efficacy of periodontal applications of a living tissue-engineered human fibroblast-derived dermal substitute. I. Comparison to the gingival autograft: a randomized controlled pilot study. Journal of Periodontology. 76(6):867-80, 2005 Jun.

Question 15

Where keratinized gingival tissue exists, the best surgical option to thicken tissue around an implant to minimize facial metal show: A. laterally repositioned flap. B. semilunar flap. C. free gingival graft. D. subepithelial connective tissue graft.

Answer 15

Answer: D Rationale: There are several indications for the use of the subepithelial connective tissue graft and dental implant sites. Thickening gingiva to eliminate metal show from the underlying dental implant is one of these indications. The subepithelial connective tissue graft can thicken the gingiva one to 3 mm, depending on the thickness of the graft and contracture/shrinkage of the graft with healing. Reference: Block M S et al, Atlas of the Oral and Maxillofacial Surgery Clinics of North America. Soft Tissue Esthetic Procedures for Teeth Implants, Subepithelial Connective Tissue Grafting with Dental Implants. Pages 95-107, Volume Seven, Number Two, WB Saunders, 1999. Block M S et al, Atlas of the Oral and Maxillofacial Surgery Clinics of North America. Soft Tissue Esthetic Procedures for Teeth Implants, A Subepithelial Connective Tissue Graft Procedure for Optimum Root Coverage. Pages 11-28, Volume Seven, Number Two, WB Saunders, 1999.

Question 16

The biologic width refers to the distance between the: A. gingival margin and the crestal bone. B. base of the sulcus and the alveolar crest. C. gingival margin and the junctional epithelium. D. base of the sulcus and the cementoenamel junction.

Answer 16

Answer: B Rationale: The biologic width is defined as the distance from the base of the sulcus to the crest of the alveolar ridge. Accurate sulcus depth can be problematic to measure with implants since there is no direct connective tissue fiber insertion into the implant surface; so in theory a periodontal probe (especially of excessive pressure is used) can pass through the top of the implant epithelial attachment (the bottom of the sulcus) to the top of the alveolar ridge crest. Biologic width (usually at least 2mm) is maintained between any microgap in the fixture/abutment interface. Reference: Misch, CE, Dental Implant Prosthetics, pages 74-75, Mosby, Inc. 2005. Fonseca, R J et al, Oral and Maxillofacial Surgery Volume Seven, Soft Tissue Considerations, page 341, WB Saunders 2000.

Question 17

For a subantral osseous augmentation, non-resorbable HA is added to autogenous bone in order to: A. add bulk to the graft. B. improve initial implant stability. C. decrease infection rate. D. improve osteogenesis.

Answer 17

Answer: A Rationale: When mixed to a 1:1 ratio with an allograft or autograft, nonresorbable hydroxyapatite helps compensate for the nature loss of bone volume that is seen with the grafts alone. It is also stable in its volume independently and therefore acts as a latticework providing structural support. Reference: Babbush, CA, Dental Implants: The Art and Science, WB Saunders, 2001, pp 158-9 Block, MS: Treatment of the single tooth extraction site, Oral Maxillofacial Surg Clin N Am 16 (2004) 41ñ63

Question 18

Local contraindications to a four-millimeter diameter posterior single tooth implant include: A. an adjacent tooth that requires a crown. B. mesiodistal bone width <7mm.

Answer 18

Answer: B Rationale: Contraindications to implant placement in this situation include inadequate bone volume of <7mm in the mesiodistal direction. Also, more than one adjacent tooth of a moderate to advanced mobility is considered unacceptable. Both adjacent teeth requiring crowns is a relative indication for a fixed partial denture restoration (influenced by the long-term prognosis of the adjacent tooth or teeth.) Reference: Misch, CE, Dental Implant Prosthetics, Mosby, 2005, pp 354-5 Manual of Dental Implants: David P. Sarment, D.D. S., M.S., page 14 Fonseca, et al. Oral and Maxillofacial Surgery: Reconstructive and Implant Surgery: (Vol 7). Pages 211-242.

Question 19

Which of the following is a limitation of the palatal connective tissue graft technique? A. High incidence of poor healing B. Dependence on smooth palate donor site C. Graft availability is dependent on donor site thickness D. High incidence of neurovascular injury

Answer 19

Answer: C Rationale: Connective tissue grafting extremely useful in that is does not depend upon a smooth palate and heals very well. The incidence of neurovascular injury is also very low if harvested in the classic manner (anterior to the maxillary first molar.) Depending upon the thickness of a particular patient’s tissue, the amount of graft available may be minimal and therefore some patients may require secondary grafting several months later. Reference: Sclar A, Alpha Omegan, Volume 93, number3, Aug/Sept 2000, pg 38-46. Fonseca, et al. Oral and Maxillofacial Surgery: Reconstruction and Implant Surgery. (Vol 7). WB Saunders Company. Philadelphia. 2000, pp 335-8.

Question 20

Which of the following is considered the least beneficial transport medium in the management of avulsed permanent teeth? A. Milk B. Saliva C. Hankís solution D. Blood

Answer 20

Answer: D Rationale: Acceptable transport media for avulsed permanent teeth include Hank’s balanced salt solution, milk, saliva (vestibule), saline, and water (if none of the above is available). Blood is not an acceptable form of transport media according to the recommended guidelines of the American Association of Endodontists since it does not replenish PDL cellular metabolites. Hank’s solution is a balanced salt solution with a physiologic pH. Reference: Recommended Guidelines of the American Association of Endodontists Peterson’s Principles of Oral and Maxillofacial Surgery Vol 1; Management of Alveolar and Dental fractures, BC Decker 2004

Question 21

Which of the following is contraindicated true regarding replantation of avulsed teeth? A. Primary teeth can be replanted within 1-2 hours following avulsion B. Ankylosis following replantation of teeth is a rare complication C. Avulsed teeth should be followed for at least 5 years to determine outcome of teeth D. Rigid splinting is recommended in most cases following replantation of avulsed teeth

Answer 21

Answer: C Rationale: Primary teeth should not be replanted following avulsive injuries. Space maintenance is however recommended in these situations. Replantation of avulsed primary teeth may cause risk of pulp necrosis and interference with development of succedaneous teeth. Reference: Recommended Guidelines of the American Association of Endodontists Fonseca Oral and Maxillofacial Trauma Vol 1; Diagnosis and Management of Dentoalveolar Injuries p 427-478, Elsevier Saunders 2005

Question 22

How long should subluxed permanent teeth be treated with a flexible splint? A. 1-2 weeks B. 3-4 weeks C. 5-6 weeks D. 7-8 weeks

Answer 22

Answer: A Rationale: A flexible splint (acid-etched) should be used for 7 to 10 days on subluxed permanent teeth. A short period of time is preferred to a longer period of time in order to prevent future complications such as ankylosis. Subluxation is the defined as movement of the teeth in any direction while concussion is the physiologic/pathologic sequela of a subluxation that affects the pulpal tissue and surround PDL. Reference: Kaban LB, et. al. Pediatric Oral and Maxillofacial Surgery. Ch. 25 Facial Trauma II: Dentoalveolar Injuries and Mandibular Fractures, Baumann A, et. al. p.446. Daniels A, Backland L: Traumatic Dental Injuries: Current Treatment Concepts. JADA 129 (10):1401-14 1998OK

Question 23

Which of the following is true regarding avulsed teeth? A. Permanent teeth with apical foramina less than 1 mm diameter have a better prognosis than those with greater an 1 mm diameter B. Avulsed permanent teeth stored in Hankís solution have a more guarded prognosis than those stored in saline C. Replanted permanent teeth should be treated with a rigid splint D. Avulsed primary teeth are not replanted

Answer 23

Answer: D Rationale: Permanent teeth with open apices greater than 1 mm diameter have a much better prognosis than those with closed apices since there is increased potential for reestablishment of pulpal circulation. Hank’s solution is considered the ideal physiologic medium for avulsed teeth. It contains sodium chloride, calcium chloride, potassium chloride and magnesium sulfate. Avulsed primary teeth are never replanted since they have poor prognosis and may cause ankylosis of the permanent tooth. Reference: Fonseca. Oral and Maxillofacial Trauma. Diagnosis and management of dentoalveolar injuries, p 427-478, 2005. OMS Reference Guide, Trauma/Emergencies, p 149-182, 2007.

Question 24

Which type of injury to teeth carries the highest degree of pulpal necrosis? A. Extrusion B. Intrusion C. Lateral luxation D. Lingual luxation

Answer 24

Answer: B Rationale: Intrusive type injuries to teeth will cause greater compression and inflammatory injury of the periapical tissues and therefore greater compromise of the pulpal vasculature and blood flow causing an incidence of 65-90% pulpal necrosis. Extrusion can cause pulpal necrosis in 64% of the time; Luxations account for the lowest incident of pulpal necrosis. Reference: Fonseca. Oral and Maxillofacial Trauma. Diagnosis and management of dentoalveolar injuries, p 427-478, 2005. Peterson. Principles of Oral and Maxillofacial Surgery. Management of alveolar and dental fractures, p 383-400, 2006. Andreasen JO. Luxation of permanent teeth due to trauma: a clinical and radiographic follow-up study of 189 injured teeth. Scan J Dent Res 1970, 78: 273.

Question 25

Which of the following root fractures has the best prognosis? A. Horizontal fracture in the apical 1/3 of the root B. Horizontal fracture in the coronal 1/3 of the root C. Horizontal fracture in the middle portion of the root D. Vertical fracture of the root

Answer 25

Answer: A Rationale: Fractures in the apical 1/3 of roots have the best prognosis for survival since the apical portion of the root is completely embedded in alveolar bone and surrounding PDL.Serial follow up evaluations are indicated. In many instances, endodontic therapy may not be indicated. Vertical root fractures require extraction since the entire pulp chamber is injured in this type of fracture. Reference: Fonseca. Oral and Maxillofacial Trauma. Diagnosis and management of dentoalveolar injuries, p 427-478, 2005. Peterson. Principles of Oral and Maxillofacial Surgery. Management of alveolar and dental fractures, p 383-400, 2006.

Question 26

What is the recommended treatment for permanent teeth with vertical root fractures? A. Splinting the teeth for 2 weeks B. Splinting the teeth for 6 weeks C. No treatment is necessary D. Extraction

Answer 26

Answer: D Rationale: All primary and permanent teeth with vertical root fractures must be extracted. These teeth have poor prognosis. Reference: Fonseca. Oral and Maxillofacial Trauma. Diagnosis and management of dentoalveolar injuries, p 427-478, 2005. Peterson. Principles of Oral and Maxillofacial Surgery. Management of alveolar and dental fractures, p 383-400, 2006.

Question 27

During extraction of erupted premolars to facilitate orthodontics, which tooth is most likely to have a root fracture during extraction? A. Maxillary first premolar B. Maxillary second premolar C. Mandibular first premolar D. Maxillary second premolar

Answer 27

Answer: A Rationale: The maxillary first premolar root usually bifurcates into buccal and palatal roots which are often thin and slightly curved. This predisposes this premolar to root fractures with extraction. Maxillary second premolars and mandibular first and second premolars usually have single roots.

Question 28

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

Answer 28

Answer: D Rationale: In general, roots with periapical lesions should be removed whenever possible, even if they are near the maxillary sinus floor. The patient’s age less than 50 should not be a factor in the decision. All OMSs should possess adequate skill and experience to remove root tips.

Question 29

Which of the following conditions are 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. Loss of periodontal support D. Dentigerous cysts

Answer 29

Answer: C Rationale: The most common problems associated with retained third molars are loss of periodontal support on the adjacent second molar and pericoronitis. Numerous studies have documented the presence of periodontal pathogens and loss of periodontal support at the distal of the second molar and third molar. This condition has been shown to progress with age. Acute pericoronitis is also a relatively common finding and if third molars are not removed, the condition is likely to recur and / or occur with another third molar. 60% of patients with pericoronitis experienced symptoms associated with the contralateral third molar within the previous 12 months. Other types of pathology such as resorption of adjacent tooth roots or odontogenic cysts are less common.

Question 30

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 30

Answer: A Rationale: Typically, in the anterior region where esthetics is a concern, a scalloped submarginal incision is preferred. However, contraindications to this approach are periodontal breakdown, a large periapical lesion, and a short root. In these cases, a full thickness sulcular incision with one or two releasing incisions is preferred. A sulcular incision may also used to avoid placing an incision over an underlying bony defect.

Question 31

Which of the following factors are associated with a favorable outcome when 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 31

Answer: D Rationale: Incomplete root formation is a favorable factor when repositioning a tooth. All the other factors listed would increase the difficulty of uprighting the second molar. The procedure is best performed after 2/3 of root development is completed. At this stage the risk of root fracture is minimal. Performing this procedure when less than 2/3 of root development has been completed could result in the second molar floating in its new position. Although the procedure has been performed when root development is complete, the incidence of subsequent pulpal necrosis or calcification is increased.

Question 32

The CT scans below are of a patient who presented to the emergency department with a history of instantaneous painless swelling during surgical extraction of an erupted maxillary molar by a general dentist. What is the most appropriate management? (air emphysema) A. Observation B. Transcutaneous puncture aspiration C. Arteriogram & selective embolization D. Surgical exploration

Answer 32

Answer: A Rationale: The CT scan depicts air emphysema. Although hemorrhage should be included in the differential diagnosis, the scan clearly depicts air and not blood. Most cases of surgical emphysema following dental treatment (72%) involved the use of high-speed air-turbine drills and air syringes. Surgical emphysema is characterized by soft tissue swelling of sudden onset, usually developing within seconds or minutes. Palpation of the affected tissues shows crepitus or crackling, an important diagnostic feature. Discomfort is a variable finding. Some patients complain of severe pain, but usually the discomfort is mild and resolves within a few days. Most cases of subcutaneous emphysema will begin to resolve after 2 to 3 days of supportive treatment, and residual swelling is usually minimal after 7 to 10 days of observation. Treatment is usually conservative, and consists of antibiotic coverage to prevent infection. Oral bacteria may possibly be carried with the aerosol into the soft tissue and represent a potential nidus of infection. Additionally, a course of systemic corticosteroids may promote faster resolution. Surgical decompression of the extensive emphysema should not be routinely used, because it is likely to be ineffective and may even worsen or spread the emphysema.

Question 33

The most frequent location for an impacted supernumerary tooth is: A. maxillary central incisor region. B. maxillary canine region. C. maxillary third molar region. D. mandibular premolar region.

Answer 33

Answer: A Rationale: The most frequent site for supernumerary teeth is the maxillary central region, followed by the maxillary lateral incisor region and the maxillary canine region.

Question 34

Which tooth orientation is generally the most difficult mandibular third molar impaction to remove? A. Mesioangular B. Distoangular C. Horizontal D. Vertical

Answer 34

Answer: B Rationale: The distoangular impaction is the most difficult mandibular third molar to remove owing to the path of delivery into the ascending ramus. This situation often necessitates a considerable amount of ostectomy and multiple sectioning of the tooth.

Question 35

Coronectomy is an alternative technique for the management of an impacted mandibular third molar when: A. there is periapical infection. B. the tooth is mobile. C. the root is intimately associated with the inferior alveolar nerve. D. the tooth is horizontally impacted along the course of the inferior alveolar nerve.

Answer 35

Answer: C Rationale: Coronectomy is a viable technique in those cases where removal of an impacted third molar might put the inferior alveolar nerve at considerable risk of damage. Infection, tooth mobility, and horizontally impacted teeth adjacent to the nerve are contraindications for this technique.

Question 36

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 3mm 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 36

Answer: C Rationale: The problem of inferior alveolar nerve involvement during the removal of lower third molars is a clinical and, more recently, medicolegal issue. Because the results of damage to the inferior alveolar nerve are unpredictable in that many cases do recover but some do not, it is preferable to carry out a technique that may reduce the possibility of this involvement. The technique of coronectomy, partial odontectomy, or deliberate root retention, is one such technique. The best technique for partial odontectomy involves sectioning of the tooth at a 45 degree angle (as measured bucco-lingually) followed by further reduction to reduce the remaining fragments 3 mm below the crestal bone level. The distance of 3 mm has been validated by animal studies to allow bone formation over the retained root fragments. Primary closure is indicated to reduce the risk of postoperative infection. The technique of coronectomy seems to be a safe and straightforward technique with few complications or potential complications. In Pogrel’s series, there has only been one case of mild, transient (5 days) lingual paresthesia, presumably caused by the lingual retraction, but no other cases of lingual nerve involvement were reported. Other studies, however, have suggested a higher rate of transient lingual paresthesias from the use of the lingual retractor but not permanent cases of lingual nerve involvement. There does not seem to be any need to treat the exposed pulp of the tooth, and root treatment actually seems to be contraindicated. Animal studies have shown that vital roots remain vital with minimal degenerative changes.

Question 37

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 37

Answer: B Rationale: Prophylactic antibiotic therapy for asymptomatic impacted third molars in healthy patients is not indicated. For the compromised patient or one who is actively infected, antibiotic administration should be timed so that incision is performed at the peak systemic concentration.

Question 38

Bleeding encountered during exploration for this displaced, previously impacted (infra temporal space), maxillary third molar would most likely emanate from the: A. pterygoid venous plexus. B. sphenopalatine artery. C. descending palatine artery. D. masseteric artery.

Answer 38

Answer: A Rationale: This scan depicts a tooth displaced into the infratemporal fossa. Maxillary third molars that are superiorly positioned may have only a thin layer of bone separating them from the infratemporal space. Venous bleeding from the pterygoid plexus of veins often makes visualization of the tooth difficult.

Question 39

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 39

Answer: B Rationale: The surgical exposure of an impacted tooth should be carried out conservatively so that only enough bone and soft tissue is removed to place on orthodontic bracket. Damaging effects to the periodontium have been shown to be more frequent with exposure of the CEJ.

Question 40

The posterior extension of an incision designed for removal of an impacted mandibular third molar is extended laterally because: A. this design places the incision in keratinized tissue. B. this design avoids injury to the buccal artery. C. this design avoids injury to the lingual nerve. D. this design reduces postoperative trismus.

Answer 40

Answer: C Rationale: The incision design for removal of impacted third molar flares laterally to avoid possible injury to the lingual nerve. The mandibular ramus flares laterally and the lingual nerve extends above the lingual crest 10% of the time.

Question 41

While attempting to extract an 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 41

Answer: D Rationale: Upper third molars can be displaced distally into the infratemporal space if excessive distal elevation is used without placement of retraction distal to the tooth. In this particular case, the new finding of restricted opening gives a clue that the tooth is not in the maxillary sinus, but most probably impinging on the coronoid process, and thus is in the infratemporal fossa.

Question 42

What is the most frequent postoperative complication of third molar extraction? A. Localized alveolar osteitis B. Subperiosteal abscess C. Inferior alveolar nerve injury D. Lingual nerve injury

Answer 42

Answer: A Rationale: In a prospective study involving 63 surgeons, 3,760 patients, and 8,333 third molars; it was found that the incidence of localized alveolar osteitis was 12% in mandibular molars. Other complication rates were: infection 1%, IAN injury 1.1-1.7%, Lingual nerve injury 0.3%.

Question 43

What is the frequency with which the lingual nerve runs superior to the lingual crest of the mandible? A. < 5% B. 10% C. 30% D. 50%

Answer 43

Answer: B Rationale: In a clinical study utilizing magnetic resonance imaging of the mandibles of normal human subjects, the lingual nerve was found to be on average 2.8mm inferior to the lingual crest and 2.5mm medial to the lingual plate. In 10% of the group, the lingual nerve was above the lingual crest and 25% were in direct contact to the lingual plate.

Question 44

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. Diversion of the inferior alveolar canal

Answer 44

Answer: A Rationale: IAN exposure is associated with increased incidence of IAN injury1. The radiographic finding linked with the most relative risk is darkening of the third molar tooth root 2. All other answers are associated with IAN exposure, but to a lesser amount.

Question 45

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 45

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.

Question 46

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 46

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.

Question 47

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 47

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.

Question 48

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 48

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.

Question 49

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 49

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.

Question 50

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 50

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.

Question 51

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 51

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.

Question 52

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 52

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.

Question 53

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 53

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.

Question 54

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 54

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.

Question 55

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 55

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.

Question 56

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 56

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.

Question 57

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 57

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.

Question 58

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 58

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.

Question 59

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 59

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.

Question 60

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 60

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.

Question 61

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 61

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.

Question 62

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 62

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.

Question 63

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 63

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.

Question 64

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 64

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.

Question 65

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 65

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.

Question 66

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 66

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.

Question 67

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 67

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.

Question 68

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 68

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.

Question 69

Appropriate placement of an endosseous dental implant is determined by: A. Placing the implant where available bone exists. B. Where the patient expects the implant to be placed. C. A surgical guide fabricated for the placement of the implant. D. Placing the implant where adequate soft tissue exists to submerge the implant.

Answer 69

ANSWER: C RATIONALE: Implant placement should be guided by the prosthetic requirements, and may be best accomplished by using a surgical guide. Contemporary tissue grafting and regenerative techniques allow fixture placement in prosthetically appropriate positions.

Question 70

Regarding platelet rich plasma is use in bone grafting procedures, which statement is most accurate? A. It involves bank blood, concentrate added to a bone graft. B. Autologous whole blood containing leukocytes and fibrinogen which promote clotting within the graft C. Primary use is in the donor site to prevent an osseous defect. D. Efficacy stems from concentration of growth factors by sequestering and concentrating autologous platelets.

Answer 70

ANSWER: D RATIONALE: Platelet-rich plasma is an autologous source of platelet-derived growth factor and transforming growth factor beta that is obtained by sequestering and concentrating platelets by centrifugation. This technique produces a concentration of human platelets containing growth promoting substances (including platelet-derived growth factor and transforming growth factor beta) within them. These growth factors increase the maturation rate 1.5 to 2 times compared to grafts without platelet-rich plasma.

Question 71

What is the minimum radiographically safe minimal distance that an implant may be placed from the superior lamina of the inferior alveolar canal when utilizing a panoramic radiograph? A. 0.5 mm B. 1.0 mm C. 2.0 mm D. 5.0 mm

Answer 71

ANSWER: C RATIONALE: When using a panoramic radiograph, variations in vertical magnification within the radiographic image make a safety margin of 2.0mm between the end of the implant and the inferior alveolar canal desirable. Because of its greater precision, computed tomography enables the clinician to select an implant that will be 1.0mm above the canal. Implant burs vary depending on the manufacturer and the surgeon must understand that the specified length (for example, a 10mm marking) may not reflect an additional millimeter included for drilling efficiency.

Question 72

The recommended solution for irrigation during implant site preparation is: A. chilled normal saline B. chilled sterile water C. body temperature Dextrose 5% in sterile water D. body temperature sterile water

Answer 72

ANSWER: A RATIONALE: Chilled solution is recommended for better cooling. Water, and other hypotonic solutions have been shown to cause rapid death of bone cells.

Question 73

Peri-implantitis can be categorized as: A. an early failure B. a late failure C. a complication of overheating of the bone D. a complication of rough –surface implants

Answer 73

ANSWER: B RATIONALE: Peri-implantitis is defined as radiographically detectable peri-implant bone loss occurring after initial successful osseointegration combined with soft tissue inflammation lesion that demonstrates suppuration and probing depths of 6mms or more. The process begins at the coronal aspect of the implant, whereas the more apical portion remains clinically stable (osseointegrated).

Question 74

Using the buccal object rule, if the x-ray cone is moved away from the area in question, and the crown of an impacted tooth (when compared to adjacent erupted tooth roots) appears to move in the same direction as the cone, the crown is considered to have which position compared to the erupted tooth roots? A. buccal B. gingival C. palatal/lingual D. distal

Answer 74

ANSWER: C RATIONALE: The SLOB rule states: “Same Lingual Opposite Buccal.” In this situation, the cone was moved away and the crown of the impacted tooth moved in the same direction (same), so the object is palatal or lingual to the adjacent erupted tooth roots.

Question 75

Which of the following fuided tissue membrane material is non-resorbable? A. polylactic acid B. glycolide and trimethylene carbamate copolymer C. expanded polytetrafluoroethylene D. freeze-dried xenographic lamellar bone

Answer 75

ANSWER: C RATIONALE: Exanded polytetraflurothylene is the most studied and widely used non-resorbable material used for guided tissue regeneration. The other listed materials are resorbed and avoid the necessity of a procedure to harvest a non-resorbable material.

Question 76

Which syndrome is not associated with multiple impacted teeth? A. Cleidocranial dysplasia B. Down syndrome C. Gardner syndrome D. Peutz-Jaeger syndrome

Answer 76

ANSWER: D RATIONALE: Peutz-Jaeger syndrome exhibits autosomal dominant inheritence, peroral ephilides, and nonmalignant intestinal polyposis. There are no supernumerary or impacted teeth associated with this syndrome. Cleidocranial dyspalsia is inherited autosomal dominant and the patients usually have short stature, long necks with drooping shoulders due to absent or hypoplastic clavicles. These patients may exhibit maxillary hypoplaisa with possible submucous clefting and supernumerary teeth. Down syndrome (also known as trisomy 21) is usually caused by mititoc chromosomal nondisjunction, resulting in an extra chromosome. Variable mental retardation, congenital heart disease, T cell and B cell dysfunction, increased incidence of acute lymphocytic leukemia, predilection for Alzheimer disease, fissured tongue, macroglossia, oral cefting, and multiple impacted teeth are all features of Down syndrome. Gardner syndrome is also autosomal dominant with premalignant intestinal polyposis, multiple osteomas, fibromas of the skin, epidermal trichilemmal cysts, and supernumerary impacted teeth.

Question 77

Surgical uprighting of a mesioangular impacted mandibular second molar will usually also require: A. removal of buccal bone B. bonding of a bracket C. removal of the adjacent impacted third molar D. intentional root fracture

Answer 77

ANSWER: C RATIONALE: Removal of buccal bone is not advised as the second molar may not be stable when uprighted. A bracket is usually unnecessary. Intentional root fracture will doom the procedure. Removal of the impacted third molar is often necessary to create space, since the uprighting cause distalization of the second molar crown.

Question 78

The lingual nerve lies above the mandibular 3rd molar alveolar crest which percentage of the time? A. 14 B. 32 C. 68 D. 86

Answer 78

ANSWER: A RATIONALE: The lingual nerve has been found to be superior to the lingual alveolar crest in the third molar region 14.07% of the time.

Question 79

Upon extraction of a tooth, the healing process begins. The major source of angioblastic and fibroblastic proliferation in the post extraction socket is derived from the: A. open marrow space surrounding the socket. B. cortical walls of the socket. C. remnants of the periodontal ligament. D. surrounding gingival tissue.

Answer 79

ANSWER: C RATIONALE: The cortical bone between the coagulum and the cancellous bone would act a barrier to the healing of the dental alveolus except for the presence of the periodontal ligament. The periodontal ligament is a major source for angioblastic and fibroblastic proliferation into the blood coagulum.

Question 80

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 80

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.

Question 81

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 81

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.

Question 82

Bone 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 82

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.

Question 83

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 83

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.

Question 84

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

Answer 84

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.

Question 85

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

Answer 85

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.

Question 86

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 86

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.

Question 87

Success after replantation of an avulsed tooth that was preserved in a clean and moist container by the patient is most dependent on: A. sterilization before replantation. B. replantation within 30 minutes after avulsion. C. curettage of the tooth root and socket. D. rigidity of fixation splinting.

Answer 87

Answer: B Rationale: Optimal success of treatment is to replant and stabilize avulsed teeth within 2 hours. The PDL cells become irreversibly necrotic after this time frame. Treatment with a nonrigid splint will allow movement of the tooth, allowing the PDL to heal. Reference: Abubaker AO, Giglio JA, Mourino AP, Diagnosis and management of dentoalveolar injuries. In:Fonseca RJ:Oral and Maxillofacial Surgery, Vol 1. W.B. Saunders Co, Philadelphia, 2000. Miloro M, et al. Peterson’s Principles of Oral and Maxillofacial Surgery, 2nd Edition. Pg 394-5. BC Decker Inc, 2004.

Question 88

Failure after replantation of an avulsed tooth occurs mostly due to: A. internal resorption, external resorption, pulpal necrosis. B. external resorption, ankylosis, periodontal disease. C. internal resorption, tooth migration, ankylosis. D. external resorption, pulpal necrosis, periodontal disease.

Answer 88

Answer: A Rationale: The most common tooth avulsed is the maxillary central incisor. Treatment is geared towards early re-establishment of the PDL cell physiology, via solutions with physiologic pH and osmolarity. Re-implant and stabilize the tooth within two hours of avulsion. Reference: Abubaker AO, Giglio JA, Mourino AP, Diagnosis and management of dentoalveolar injuries. In:Fonseca RJ:Oral and Maxillofacial Surgery, Vol 1. W.B. Saunders Co, Philadelphia, 2000. Miloro M, et al. Peterson’s Principles of Oral and Maxillofacial Surgery, 2nd Edition. Pg 393-395. BC Decker Inc, 2004.

Question 89

Generally speaking, soft tissue injuries associated with dentoalveolar trauma are treated: A. before management of all hard tissue injuries. B. after management of all hard tissues injuries. C. before management of bony injuries, but after management of dental injuries. D. should never be closed primarily but should be allowed to heal by secondary intention.

Answer 89

Answer: B Rationale: Soft tissue wounds associated with dentoalveolar trauma are always treated after management of the hard tissue. This prevents wasting time of suturing wounds that are likely to be removed or compromised during the intraoral manipulation to treat the hard tissue or dental injuries. Reference: Peterson LJ, Contemporary Oral and Maxillofacial Surgery, 2nd edition, Ed. Pg. 583. JB Lippincott Co., Philadelphia 1992

Question 90

Treatment for inflammatory fibrous hyperplasia where areas of gross tissue redundancy are present, is best treated by excision with: A. electrosurgical technique. B. laser technique. C. primary closure. D. secondary epithelialization.

Answer 90

Answer: D Rationale: When areas of gross tissue redundancy are found, excision frequently results in total elimination of vestibule. In such cases excision of the epulides, with peripheral mucosal repositioning and secondary epithelialization, is preferred. Reference: Ochs, MW, Tucker, MR; Preprosthetic Surgery in Peterson, Ellis, Hupp, Tucker. Contemporary Oral & Maxillofacial Surgery 4th edition. Page 274, Mosby, 2003 USA.

Question 91

Which of the following is true regarding submucosal vestibuloplasty? A. A postoperative stent is essential B. A superiosteal dissection is performed C. Split-thickness skin grafts are required D. Commonly used in the mandible

Answer 91

Answer: A Rationale: Distortion/inversion of the upper lip when a mirror is placed to the depth of the maxillary anterior vestibule indicates a lack of vestibular depth (which is why the lip distorts). The Submucous vestibuloplasty is contraindicated in this instance. An open type vestibuloplasty with secondary skin graft or laser vestibuloplasty is a better choice. Reference: Spagnoli, DB, Gollehon, SG, Misiek, DJ; Preprosthetic and Reconstructive Surgery in Peterson’s Principles of Oral and Maxillofacial Surgery, Miloro, M. et al., Editors, Second Edition, BC Decker Inc, 2004, pp. 174-175

Question 92

For alveolar distraction to be successful to increase alveolar ridge height and width it is imperative that the: A. transport segment not be stabilized by screws to prevent resorption. B. periosteum be maintained on the crestal alveolus of the transport segment. C. transport segment be increased in size due to resorption during the process. D. process be completed as quickly as possible.

Answer 92

Answer: B Rationale: Distraction of the alveolus is successful only if the periosteal blood supply is maintained to the transport segment. The segment must be secured to the device to keep it stable during the process by rigid fixation. Minimal resorption of the transport segment occurs due to the intact periosteal blood supply. The process must be governed by the latency, activation, and consolidation phases and not hurried Reference: Spagnoli, DB, Gollehon, SG, Misiek, DJ; Preprosthetic and Reconstructive Surgery in Peterson’s Principles of Oral and Maxillofacial Surgery, Miloro, M. et al., Editors, Second Edition, BC Decker Inc, 2004, pp183-4

Question 93

One of the mos tcritical complications involved in genial tubercle reduction is: A. over-reduction of the tubercle. B. under-reduction of the tubercle. C. partial detachment of the genioglossus muscle. D. hematoma of the floor of the mouth.

Answer 93

Answer: D Rationale: Reduction of the genial tubercle is performed to create an appropriate base for a denture when significant mandibular resorption has occurred. Under reduction will not provide the desired alveolar surface, over reduction may result in complete muscle detachment and difficulty swallowing for several months until reattachment occurs. The genioglossus muscle is partially detached or may require complete detachment to adequately reduce the tubercle, it will re attach independently. Floor of the mouth hematoma may cause airway embarrassment and an emergent situation. Reference: Spagnoli, DB, Gollehon, SG, Misiek, DJ; Preprosthetic and Reconstructive Surgery in Peterson’s Principles of Oral and Maxillofacial Surgery, Miloro, M. et al., Editors, Second Edition, BC Decker Inc, 2004, pp169-170. Davis et al. Soft Tissue Procedures in Reconstructive and Preprosthetic Surgery, Fonseca and Davis Editors, Second Edition. WB Saunders Co., 1995. pp748, 759-760

Question 94

Which of the following statements is true regarding alveolar distraction? A. The consolidation period is the time after the osteotomy and prior to distraction B. Activation occurs 3mm/day in 3 divided, equal segments per day C. The consolidation phase should be three times the length of the active distraction period D. The latency period should be shortened for distraction of irradiated bone

Answer 94

Answer: C Rationale: After the osteotomy is performed and the distraction device placed, a latency period must be observed. The latency period can be from 4-7 days depending on age of patient, blood supply, irradiation to the area, scar tissue, etc. Secondary to impaired blood supply, the latency period should be longer in irradiated bone. The latency period is followed by the active distraction period which varies depending on the transport distance. The rate and rhythm of distraction is how far and how often. A rate of 1mm/day at a rhythm of .25mm four times a day is ideal. The consolidation period begins when active distraction stops and is generally three times the active distraction period. Reference: Spagnoli, DB, Gollehon, SG, Misiek, DJ; Preprosthetic and Reconstructive Surgery in Peterson’s Principles of Oral and Maxillofacial Surgery, Miloro, M. et al., Editors, Second Edition, BC Decker Inc, 2004, pp184-5

Question 95

When performing a maxillary labial frenectomy where the base of the frenum is wide, the most effective surgical technique is: A. Z-plasty technique. B. simple excision (“diamond” excision). C. localized vestibuloplasty with secondary epithelialization. D. kazanjian technique (lip switch).

Answer 95

Answer: C Rationale: Localized vestibuloplasty with secondary epithelialization has been described as the most beneficial for broad frenum attachments. The Z-plasty technique is useful when the mucosal and fibrous band is narrow. The diamond excision can result in scarring and relapse. The lip-switch is used for mandibular vestibuloplasty. Reference: Fonseca, Davis. Reconstructive Preprosthetic Oral & Maxillofacial Surgery (1st Edition). Page 65, W.B Saunders Company, 1986 Philadelphia Ochs, MW, Tucker, MR; Preprosthetic Surgery in Peterson, Ellis, Hupp, Tucker. Contemporary Oral & Maxillofacial Surgery 4th edition. pp 275-278, Mosby, 2003 USA.

Question 96

Which of the following is more characteristic of a thin split-thickness skin graft(STSG) when compared to a thick STSG? A. Increased probability of graft survival B. Decreased secondary contracture of the graft C. More likely to result in recipient site hair growth D. Slower donor site re-epithelialization

Answer 96

Answer: A Rationale: The thin STSG is more likely to survive on its recipient site because it can survive well during the phase of plasmatic absorption and therefore wait longer for vascularization. The thicker the graft, the less its tendency to undergo secondary contraction; full-thickness skin grafts show little or no evidence of contracture. The thicker the graft, the more likely a hair follicle will be transplanted. The thinner a graft, the more accessory skin structures remain at the donor site for epithelial growth. Reference: Fonseca, Davis. Reconstructive Preprosthetic Oral & Maxillofacial Surgery (1st Edition). Page 35, W.B Saunders Company, 1986 Philadelphia