2006 Flashcards

Question

``` Regarding blunt force trauma to the midface, which of the following anatomic structures can be considered a pillar of support that can resist compression and deformation? A. Anterior maxillary sinus wall B. Posterior maxillary sinus wall C. Zygomatico-maxillary junction D. Zygomatico-sphenoid junction ```

Answer 1

Answer: C Rationale: There are three vertical buttresses of the midface:zygomatico-maxillary, pterygo-maxillary, and naso-maxillary. These structures consist of thicker supporting regions of bone that transmit and/or resist forces to the base of the skull. The horizontal buttresses of the midface are the (1) pyriform aperture, (2) maxillary alveolus and palate, (3) orbital rims and (4) base of the skull. Reference: Fonseca, RJ, Oral and Maxillofacial Trauma Vol 1, Advances in Maxillofacial Trauma Surgery, Elsevier 2005. Manson P, et al. Plastic and Reconstructive Surgery. Structural Pillars of the Facial Skeleton:An Approach to the Management of Le Fort Fractures. July 1980, 66(1) pg. 57.

Answer 2

Answer: C Rationale: Repair of detached medial canthal tendons during a severe naso-orbital ethmoidal fracture repair involves reattachment of one or both tendons to the posterior lacrimal crest in a slightly posterior and superior direction to overcome the forces of migration, relapse, and telecanthus. Reference: Fonseca, RJ, Oral and Maxillofacial Trauma Vol 2, Diagnosis and Treatment of Midface Fractures, Elsevier 2005

Answer 3

Answer: B Rationale: Integrity of the temporo-facial trunk of the facial nerve can be assessed by performing a corneal reflex (tearing to touching the ipsilateral cornea.) The afferent and efferent limbs of the reflex involve the first division of the trigeminal nerve and facial nerve respectively. Strabismus is associated with defects in cranial nerves III, IV, and VI. Reference: Bates, B, A Guide to Physical Examination and History Taking, The Nervous System, JB Lippincott 2002

Answer 4

Answer: C Rationale: Displaced anterior table fractures should be opened with careful inspection of the sinus mucosa. A non-displaced posterior table fracture without CSF leak can be managed without obliteration of the frontal sinus. Occlusion of the nasofrontal ducts requires removal of all sinus mucosa from the frontal sinus, inversion of the mucosa into the ducts, and elimination of dead space. This eliminates the possibility of developing a hematoma or seroma. Fat has been historically used with most success; no filler, hydroxyapatite, glass wool, bone, cartilage, muscle, absorbable gelatin sponge and fabric, acrylic have also been used.

Answer 5

Answer: C Rationale: Infraorbital or rim incision results in the worst esthetics and offers no advantages. The subciliary incision has an ectropion rate of approximately 6 %, whereas the transconjunctival incision has an ectropion/entropion rate of approximately 1.2 %. Thus, the transconjunctival incision as the approach of choice to avoid ectropion. Reference: Miloro M, et al. Peterson's Principles of Oral and Maxillofacial Surgery, 2nd Edition. BC Decker Inc, 2004.

Answer 6

Answer: D Rationale: All of the above cited answers are potential complications to frontal sinus fractures. Meningitis is the most common EARLY complication. The remainders of the answers are delayed or late potential complications. Frontal sinus complications can occur many years after injury (often greater than 20 years after injury). The most serious complications: can include displacement of the frontal bone in the brain and floor of frontal sinus into the orbit. Infectious complications, such as meningitis or intracranial abscess occur via bacterial spread through posterior table fractures or the diploe veins of Behçet; or by osteomyelitis, or mucocoele formation. Mucoceles are the most common chronic complication with diagnosis made via CT scanning. Periodic review by CT should be done every 1, 2 and 5 years following surgery. Symptoms include headache and can include loss of smell (anosmia.). Reference: Fonseca, RJ, Oral and Maxillofacial Trauma, Third Edition, 2005, Vol 2, pp 731-32. Miloro M, et al. Peterson's Principles of Oral and Maxillofacial Surgery, 2nd Edition. Pg 503. BC Decker Inc, 204.

Answer 7

Answer: A Rationale: The reconstruction plate is designed to bear the entire load of the mandibular movement across the fracture site. The remaining methods mentioned do not adequately stabilize the fracture segments and increase the possibilities for non-union and infection. Reference: Miloro, M. et al, Peterson's Principles of Oral and Maxillofacial Surgery, 2nd Edition, page 375, BC Decker INC, 2004

Answer 8

Answer: D Rationale: Full thickness skin graft from the opposite upper lid is preferred due to similar skin thickness, color, texture and availability with minimal donor site morbidity. This avoids scar and ectropion. Reference: Sandler NA, Evaluation and management of traumatic eyelid injury, OMS Knowledge Update vol 3, AAOMS, 2001

Answer 9

Answer: D Rationale: Exposed cartilage will not accept a skin graft. Composite free auricular grafts and microvascular reanastomosis have poor success rates due to poor venous drainage. The bipedicled flap nicely and predictably reconstructs the posterior helical defect. If the avulsed segment is 1 cm or less it can be reattached and allowed to revascularize. Larger avulsive injuries, the “pocket principle” can be used where the detached ear is dermabraded and reattached to the stump and then buried under a skin flap in the posterior auricular region to provide vascular supply. 2-3 weeks later the revascularize ear is uncovered and allowed to reepithelialize. Reference: Dierks EJ, Deeb GR, Evaluation and management of ear injuries, OMS Knowledge Update vol 3, AAOMS, 2001

Answer 10

Answer: A & B Rationale: Sialoceoles that repeatedly reform, even after aspiration, and pressure dressings, and antisialogogues may indicate a parotid capsular or Stensen's duct injury that requires early reexploration and repair. Sialocoele formation within 48 hours can indicate an injury to the salivary ductal system and exploration of the injury is needed. The patient also needs to have antibiotic coverage with penicillin or a cephalosporin. Reference: Fonseca RJ and Walker RV, “Management of soft tissue injuries”, Oral and Maxillofacial Trauma, vol 1, pg. 642. WB Saunders, 1991

Answer 11

Answer: D Rationale: Exposed cortical cranial bone will not accept skin grafts. Rotational-advancement flaps with multiple galeal releasing incisions parallel to the long axis of the flap will provide adequate coverage in most instances. Reference: Fonseca RJ and Walker RV, Management of soft tissue injuries, Oral and Maxillofacial Trauma, vol 1, WB Saunders, 2001

Answer 12

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.

Answer 13

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.

Answer 14

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

Answer 15

Answer: D Rationale: The retina is an extension of the brain, and will have similar reaction in the presence of ischemia. Signs and symptoms of visual impairment, severe ocular pain should be evaluated for retrobulbar hematoma. Computed tomography evaluation can demonstrate signs of retrobulbar hematoma formation, but immediate treatment with a lateral canthotomy based on clinical symptoms and signs should be completed prior to a lengthy CT scan. Other signs of optic nerve compromise include (1) afferent papillary defect (2) visual field loss and (3) color vision defects. Reference: Girotto JA, Gamble WB, Robertson B, et al, Blindness After Reduction of Facial Fractures, Plast Reconstr Surg 102:1821, 1998. Miloro M, et al. Peterson's Principles of Oral and Maxillofacial Surgery, 2nd Edition. Pg 472. BC Decker Inc, 204.

Answer 16

Answer: C RATIONALE: The emergency procedure of choice for acute visual acuity loss associated with acute orbital compartment syndrome is dissection of the lateral canthus and disinsertion of at least the inferior crus of the lateral canthal tendon, which allows complete mobility of the lower lid. Visual loss without clear signs consistent with increased IOP is not an indication for this procedure. Other primary indications for lateral canthotomy and cantholysis include an IOP greater than 40 mm Hg and proptosis, which may be used as a criterion for unconscious patients whose visual acuity cannot be determined. Secondary criteria include afferent pupillary defect, ophthalmoplegia, cherry-red macula, optic nerve head pallor, and severe pain, but these are all considered less sensitive or very late signs. Contraindication for this procedure would be a suspected ruptured globe. REFERENCE: Fonseca, RJ, Walker, R, Oral and Maxillofacial Trauma Volume 1, WB Saunders, 1991

Answer 17

Answer: C Rationale: A grossly comminuted zygomatic complex fracture will not be stable with a closed technique. Comminuted segments of the infraorbital rim are a poor guide to placement of the zygoma. The zygomatic-frontal suture is a poor reference for placement of the zygoma. In high energy grossly comminute fractures, the sphenozygomatic suture with its broad contact can aid in the anatomic reduction of the fracture. Reference: Baley JS, Goldwasser MS, Management of Zygomatic complex fractures. In: Miloro M ed, Peterson's Principles of Oral and Maxillofacial Surgery Second edition BC Deker, London 2004 Chapter 23.2 pp 452

Answer 18

Answer: A Rationale: The optic nerve and retinal tissue, unlike skeletal muscle, have been shown to be extremely sensitive to pressure and hypoxia. Irreversible ischemic damage often occurs within 60 minutes and certainly within 2 hours. Megadose steroids have been recommended during the first 8 hours following injury. The outcome in patients with traumatic optic neuropathy with no light perception on presentation is a poor prognostic factor. Likewise patient presenting with traumatic optic neuropathy after penetrating trauma have a worse prognosis than those with blunt facial trauma. Reference: Wang BH, Robertson BC, Girotto JA, Liem A, Miller NR, Iliff N, Manson P, Traumatic optic neuropathy: A review of 61 patients. Plastic Reconstructive Surg 2001; 107:1653-1664

Answer 19

Answer: C Rationale: The management of a patient with a traumatic hyphema is to use topical cycloplegics and carbonic anhydrase inhibitors to decrease intraocular pressure. Rebleeding can occur in 5- 30% of the patients with hyphema. Reference: Baley JS, Goldwasser MS, Management of Zygomatic complex fractures. In:Miloro M ed, Peterson's Principles of Oral and Maxillofacial Surgery Second edition BC Deker, London 2004 Chapter 23.2 pp 459

Answer 20

Answer: A Rationale: The diagnosis of an afferent pupillary defect in the presence of normal eye is when the pupil reacts to direct stimulation but shows a noticeably more brisk consensual response when the contralateral pupil is directly tested. It indicates an optic nerve injury. An afferent pupillary defect is also call a Marcus Gunn pupil. Pupillary symmetry is not affected by the afferent pupil defect. This implies an efferent lesion or an iris lesion or both. Reference: Gossman MD, Roberts DM, Barr CC, Ophthalmic aspects of orbital injury; A comprehensive diagnostic and management approach. Clin Plastic Surg 1992; 19:17-85

Answer 21

Answer: B Rationale: A CT scan of an orbit that has a trapdoor appearance with clinical and radiographic evidence of inferior rectus muscle incarceration is more like to occur in children than in adults and it warrants early intervention to prevent ischemic necrosis to the rectus muscle. Steroids are may be used in cases where there is no evidence of muscle entrapment and mild restricted motility. By its nature, a trapdoor defect seldom requires an implant to bridge a defect. Reference: Ochs MW, Orbital and ocular trauma. In: Miloro M ed, Peterson's Principles of Oral and Maxillofacial Surgery Second edition BC Deker, London 2004 Chapter 24 pp 479

Answer 22

Answer: B Rationale: While calcium phosphate bone cement is a near ideal alloplast in that it has unlimited availability, is biocompatible, has high mechanical strength, has a low risk for infection, is radiopaque and is incorporated into the bone, it does have drawbacks. It is expensive, and when placed directly over dura or sinus membranes, it breaks up and a chronic foreign body reaction ensues. This is particularly true for the pediatric population. Reference: D'Addario M, Haug RH, Talwar R: Biomaterials for Use in Frontal Sinus Obliteration. Journal of Long-Term Effects of Medical Implants. 14: 455-465, 2004.

Answer 23

Answer: A Rationale: β2 transferrin is one of two major variants of iron binding transferrin glycoproteins forum in several forms of various body fluids. β2 transferrin lacks a carbohydrate side chain which increases its positive charge, permitting isolation during electrophoresis. β2 transferrin is only found in cerebrospinal fluid, aqueous humor and perilymph. Thus, with the exception of contamination by a ruptured globe, it is an ideal substance to distinguish between cerebrospinal fluid, nasal secretions and serum. Reference: Brandt MT, Jenkins WS, Fattahi TT, Haug RH:Cerebrospinal Fluid:Implications in Oral and Maxillofacial Surgery. J Oral Maxillofac Surg. 60:1049-1056, 2002.

Answer 24

Answer: B Rationale: In the recumbent position, intracranial pressure, and thus cerebral spinal fluid pressure, is about 8 to 12 mm Hg or 110 to 150 mm H2O. Autoregulation maintains this pressure. Reference: Brandt MT, Jenkins WS, Fattahi TT, Haug RH:Cerebrospinal Fluid:Implications in Oral and Maxillofacial Surgery. J Oral Maxillofac Surg. 60:1049-1056, 2002.

Answer 25

Answer: D Rationale: While concomitant injury has been associated with hyphema and permanent visual loss, it is not the primary cause in traumatic hyphema. Retinal artery spasm is not associated with hyphema. Both increased intraocular pressure and traumatic mydriasis are concomitant problems. Corneal staining from myoglobin is the primary cause of permanent loss of vision. Reference: Brandt MT, Haug RH:Traumatic Hyphema: A Comprehensive Review. J Oral Maxillofac Surg. 59:1462-1470, 2001.

Answer 26

Answer: A Rationale: The respiratory apparatus and physiology in children differs from adults in many ways. Children have a high metabolic rate, thus a high oxygen demand and hypoxemia develops rapidly their upper airway has a smaller caliber, large soft tissues, larynx that is positioned cephalad, with a shorter trachea, and epiglottis that is short and narrow. This results in increased airway resistance, easy obstruction, difficult intubation, easy extubation. The child's ribs and sternum are compliant, and when respiratory efforts are diminished, their reserve decreases. The child relies more on diaphragatic breathing, therefore high intrathoracic pressure or abdominal distention diminishes ventilation. The child possesses low lung compliance and therefore ventilation is inefficient during respiratory distress. Reference: American College of Surgeons Committee on Trauma:ATLS Advanced Trauma Life Support Program for Doctors. 7th Edition, American College of Surgeons, Chicago, IL, 2004, pgs 243-262.

Answer 27

Answer: B Rationale: Children possess a higher cardiac output than adults. Under the physiologic stress of trauma, the child's stroke volume cannot increase, so that under stress proportionate increases in stroke volume cannot occur and increases in cardiac output are rate determined. Bradycardia could result in hypoxia and hypercapnia, and is ominous. The child's proportional blood volume is greater than an adult. However, the absolute blood volume and therefore tolerable absolute blood loss is less, so that minor injuries may result in blood loss which is physiologically significant. The child's blood pressure is maintained through physiologic compensation (vasoconstriction, tachycardia, myocardial contractility). This compensation may be misleading by masking volume reduction. The healthy child has an increased total systemic physiologic reserve, thus with trauma, symptoms of hypoxemia or hypovolemia may not occur until a potentially catastrophic hypovolemia has occurred. Reference: American College of Surgeons Committee on Trauma:ATLS Advanced Trauma Life Support Program for Doctors. 7th Edition, American College of Surgeons, Chicago, IL, 2004, pgs 243-262.

Answer 28

Answer: D Rationale: When considering maxillofacial injury and cervical spine injury, a cause and effect relationship exists between the mandible and cervical spine. There is also a relationship between neurocranial injury and mid- and upper-facial third facial injuries. Approximately one out of every fifty patients with a mandibular fracture will suffer a cervical spine fracture. The vast majority of these are subluxation injuries. When the mandible sustains a force applied to it, the reaction of the body is to move away from the force. This “twisting of the neck, when accentuated, results in a subluxation injury of the cervical spine. Reference: Haug RH, Wible RT, Likavec MJ, et al:Cervical spine fractures and maxillofacial trauma. J Oral Maxillofac Surg 49:725-729, 1991.

Answer 29

Answer: A Rationale: The human and animal population is very similar in their oral flora. Each has a predomination of Streptococcus species and numerous gram negative anaerobic organisms. Each has numerous species of viruses and some mycobacteria have been reported. It is however, Pasteurella multocida that is only found in the non-human population Reference: Haug RH, Assael L, “Infections in the Maxillofacial Trauma Patient”, Chapter 17 in Topazian RG, Goldberg MH, Hupp J (Eds.). Oral and Maxillofacial Infections. Philadelphia PA, W B Saunders, 2002, pp 359-380.

Answer 30

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.

Answer 31

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

Answer 32

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

Answer 33

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

Answer 34

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

Answer 35

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.

Answer 36

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 .

Answer 37

Answer: C Rationale: HBO creates an oxygen gradient in radiated tissue which does not normally exist. This steep oxygen gradient stimulates the normal wound healing mechanism that is missing in radiated tissue. The effects of HBO fall off when the tissue is sufficiently revascularized so that it no longer generates a sufficient oxygen gradient to continue the angiogenic process. Reference: Fonseca, Davis. Reconstructive Preprosthetic Oral & Maxillofacial Surgery (2nd Edition). Page 1107-08, W.B Saunders Company, 1995 Philadelphia.

Answer 38

Answer: C Rationale: Maxillary labial frenectomy should be done following the eruption of the lateral incisors and during active eruption of the maxillary canines. The combination of a correctly timed and executed maxillary frenectomy and the anterior eruption force of the maxillary canines should lead to the closure of the diastema. Reference: Kearns, G, Pediatric Dentoalveolar Surgery in Fonseca, RJ, Oral and Maxillofacial Surgery Vol 1, Anesthesia/Dentoalveolar Surgery/ Office Management, WB Saunders 2000. pp 360- 361.

Answer 39

Answer: D Rationale: Site preservation usually begins at the time of tooth removal. In aesthetic areas, the referenced author uses the Bio-Col alveolar ridge preservation technique to preserve hard and soft tissue alveolar ridge anatomy in preparation for immediate or delayed implant placement. This technique can be used to reduce or avoid osseous ridge resorption by minimizing trauma during tooth removal. The prepared extraction sockets or the voids surrounding the immediately placed implant are then grafted with Bio-Oss (Osteohealth, Shirley, NY), a natural, porous bone-grafting material. Subsequently, the grafted socket is isolated with an absorbable collagen material (Collaplug; Zimmer Dental, Carlsbad, CA) that has been coated with an impervious tissue cement (Isodent; Ellmann International, Hewlett, NY); this allows for guided bone regeneration without the need for flap elevation and primary closure, thus preserving the surrounding soft-tissue volume. Finally, the scalloped soft tissue architecture is preserved with the use of interim provisional restorations, anatomic healing abutments, or custom tooth-form healing abutments designed to support the marginal tissues and interdental papillae. This is of critical aesthetic importance for implant patients who present with thin scalloped periodontal biotypes who are predisposed to loss of alveolar ridge volume secondary to remodeling, resorption of bone following tooth removal, and soft tissue recession following subsequent surgical or restorative interventions. Reference: Sclar AG, Strategies for management of single-tooth extraction sites in aesthetic implant therapy. J Oral N:Maxillofac Surg. 2004 Sep;62(9 Suppl 2) 90-105. Sclar AG, Preserving alveolar ridge anatomy following tooth removal in conjunction with immediate implant placement. The Bio-Col technique. Atlas Oral Maxillofac Surg Clin North Am. 1999 Sep;7(2): 39-59.

Answer 40

Answer: C Rationale: Bisphosphonates are widely used in the management of metastatic disease to the bone and in the treatment of osteoporosis. Recently, there is emerging evidence that these drugs are etiologically related to osteonecrosis of the jaws. Answer A is incorrect because primary closure is not possible or required. Although radiotherapy is known to be a cause of osteonecrosis, the stem of the question explicitly indicates radiation to the chest; therefore, option B is incorrect. Option D is also incorrect since even if traumatic extraction of a tooth occurred, healing should have been complete after six weeks, even without appropriate home care. Reference: Ruggiero, S.L., Mehrotra, B., Rosenberg, T.J., and Engroff, S.L.:Osteonecrosis of the Jaws Associated with the use of Bisphosphonates:A Review of 63 cases. J. Oral Maxillofac Surg 62:527-534, 2004.

Answer 41

Answer: D Rationale: The correct answer to this question requires specific knowledge of the morphology of fungi. Aspergillus forms fruiting bodies and septate filaments branching at acute angles. Candida grows as yeast forms, tandem arrays of elongated forms without hyphae (pseudohyphae), and true hyphae with septate. Actinomyces is a gram-positive filamentous or rod-shaped bacteria. Mucormycosis form nonseptate, irregularly wide fungal hyphae with frequent right-angle branching. In addition mucormycosis frequently occur in diabetics and may spread from nasal sinuses to the orbit and brain-giving rise to rhinocerebral mucormycosis. Reference: Regezi:Oral Pathology:Clinical Pahtologic Correlations, 4th., 2003 Elsevier, pp 37-38. Strauss, R.A.:Fungal Infections of the Head and Neck, In:Oral & Maxillofacial Surgery Clinics of North America. Vol. 3, Number 2, W. B. Saunders 1991, pp 295-309.

Answer 42

Answer: B Rationale: Acute oroantral communication is a common occurrence during extraction of the posterior maxillary teeth. In most instances these perforations are small and the blood clot that fills the extraction site usually seals such small perforations. If there is an infection in the antrum, the defect is large (>5 mm in diameter), the gingival tissue are not approximated, the wound is dehisced, or the patient does not follow the postoperative instructions, an oro-antral fistula occurs. Although option A seems reasonable for a small fistula, due to the size of the defect, local suturing without flap development will most likely not result in primary closure, and then result in an oro-antral communication. Option B offers the best chance of primary closure of the large communication and prevents development of de novo sinusitis. A free graft cannot survive over a hole without its own blood supply and thus option C is incorrect. Option D is also incorrect because it treats chronic sinusitis. There is no indication in the stem of the question that sinusitis occurred. Closure of the communication is not addressed. Reference: Laskin, D.M.:Management of Oro-antral fistula and other sinus-related complications. In:Oral Maxillofac Surg Clinic North America Vol. Number 1, Feb. 1999, W.B. Saunders, Philadelphia, pp 155-179.

Answer 43

Answer: B Rationale: The mylohyoid muscle forms the floor of the mouth attaching to the mylohyoid ridge. The latter curves superiorly as it approaches the third molar. Roots of first molars are usually superior to level of mylohyoid muscle attachment to the mandible. The root tips of third molars are usually inferior to the muscle attachment. Also, the lingual plate is thin in this site. Therefore, option B is correct. Options A and D are both incorrect since extensive procedures that may not gain visualization of the displaced root, are required. Option C is incorrect because anatomically the root is likely to be superior to mylohyoid. If a third molar root was displaced, it may be inferior to the mylohyoid. In this latter situation the submandibular approach may be necessary. Reference: Gregg, J.M.:Surgical Anatomy. In Oral and Maxillofacial Surgery, Vol. 1, edit:D.M. Laskin. The C.V. Mosby Company, St. Louis, 1980, pp 3-49. Pogrel, M.A.:Complications of Third Molar Surgery. In Oral and Maxillofacial Surgery Clinics of North America Vol 2, Number 3, 1990, W.B. Saunders Company. Pp. 441-451.

Answer 44

Answer: B Rationale: The palatal root of the maxillary first molar is usually the most closely related to the floor of the maxillary sinus. Reference: Alling CC (Ed). Dentoalveolar Surgery. Oral and Maxillofacial Surgery Clinics of North America. Vol 5. WB Saunders. Philadelphia, 1993

Answer 45

Answer: C Rationale: The most appropriate first step in this situation is to attempt visualization and retrieval of the displaced root tip through the extraction socket. If that is unsuccessful subsequent measures should include further radiographic documentation of the root tip position and discussing the operative findings with the patient. Initial localization with periapical or panorex x-rays would be appropriate. If conservative surgical approaches are unsuccessful, then a Caldwell- Luc may be appropriate. In general, root tips between 1mm and 3mm and are without infection or pathology can be managed expectantly. A root that is 2mm or greater and exhibits infection or pathology should be removed.

Answer 46

Answer: A Rationale: Intrusive forces are more likely to cause direct compressive injury to the pulpal vascular supply than forces in any other direction. The risk of pulpal necrosis after intrusion of teeth with a closed apex is 95% and 65% if the apex is open. Reference: Andreassen JO, Andreassen FM:Essentials of Traumatic Injuries to the Teeth 2nd Edition; Munksgaard, Copenhagen, 2000, pp 77-112.

Answer 47

Answer: C Rationale: MTA, IRM, and SuperEBA all have success rates greater than that of a retrograde amalgam. Following retrograde preparation with an ultrasonic microtip or use of intraoperative magnification, the success rates of these three materials range from 85-97%. The success rate of traditional retrograde amalgam filling is reported to be much lower, around 68%. Reference: von Arx T. Failed root canals: the case for apicoectomy (periradicular surgery). Journal of Oral & Maxillofacial Surgery. 63(6):832-7, 2005 Jun.

Answer 48

Answer: B Rationale: Cracked tooth syndrome frequently occurs in teeth that have had 1 or more restorations in the marginal ridge area. The tooth frequently exhibits pain on release of bite force, rather than on percussion. Restoration with onlays, composite resin, or splinting with an orthodontic band is frequently successful. Extraction is necessary only if the tooth root fractures vertically. Reference: Homewood CI. Cracked tooth syndrome--incidence, clinical findings and treatment. Australian Dental Journal. 43(4):=217-22, 1998 Aug.

Answer 49

Answer: A Rationale: These are axial CT scans of air emphysema. The use of a high-speed dental handpiece for the procedure and the instantaneous swelling are characteristic of this phenomenon. The air was introduced by the handpiece into the cheek, and has progressed along fascial planes into the carotid sheath and then the mediastinum. The treatment of tissue emphysema varies with the severity of the condition. 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. In most cases the patient can be discharged with an explanation of the nature of the tissue emphysema and its course. Reference: Peterson LJ. Emphysema and dental drill (comment). J Am Dent Assoc 1990; 120:423 Pynn BR, Amato D, Walker DA. Subcutaneous emphysema following dental treatment:report of two cases and review of the literature. J Can Dent Assoc 1192; 58:496-499 Schuman NJ, Edwards BC, Walker W. Subcutaneous emphysema during operative dentistry:report of a case with a thirty-month follow up. J Oral Med 1983; 38:168-169 Woehrlen AE. Subcutaneous emphysema. Anesth Prog 1985; 32:161-163 Salib RJ, Valentine P. Surgical emphysema following dental treatment. The Journal of Laryngoscopy and Otology 1999; 113:756-758

Answer 50

Answer: A RA TIONALE: If the alveolus is fractured, dissect the alveolus off the root, replace the periosteum and alveolus which will act as a vascularized graft. If soft tissue is inadvertently dissected from the alveolus, the segment of bone will likely undergo necrosis. If the maxillary tuberosity is fractured, and the tooth cannot be dissected from the alveolus, replace and splint for 6 – 8 weeks. Later surgically extract the tooth. If the tuberosity is completely avulsed without soft tissue pedicle, then smooth the remaining bony edges and close, checking for oral antral communication. Reference: Peterson, LJ; Prevention and Management of Complications in Peterson, Ellis, Hupp, Tucker. Contemporary Oral & Maxillofacial Surgery 4th edition. pp 228-230., Mosby, 2003 USA. Peterson LJ:Contemporary Oral and Maxillofacial Surgery, 3rd edition Ed. Pg. 261 – 262. Mosby, Missouri

Answer 51

Answer: B Rational: Minimal manipulation of the segment will provide the greatest chance of maintaining the periosteal attachment, and thus the blood supply to the segment. If soft tissue is inadvertently dissected from the alveolus, the segment of bone will likely undergo necrosis. Removal of the segment is generally not advised, dissection in this region would increase the risk of injury to the lingual nerve. REFERENCE: Berman SA. Basic principles of dentoalveolar surgery. In:=Petersen LJ, Indresano AT, Marciani RD, Roser SM. Principles if Oral and Maxillofacial Surgery. Philadelphia, PA; JB Liincott CO; 1992, pp. 95-96. Peterson, LJ; Prevention and Management of Complications in Peterson, Ellis, Hupp, Tucker. Contemporary Oral & Maxillofacial Surgery 4th edition. pp 228-230., Mosby, 2003 USA. Peterson LJ:Contemporary Oral and Maxillofacial Surgery, 3rd edition Ed. Pg. 261 – 262. Mosby, Missouri

Answer 52

Answer: B Rationale: An appreciation of biologic width is important in best determining implant positioning to allow for an aesthetic result. Numerous studies document the dimensions of biological width for both natural teeth and implants. Biologic width is comprised of the zone of supracrestal connective tissue that measures approximately 1 mm and epithelial structures, including the junctional and sulcular epithelium that measure about 2 mm in height. Reference: Burglund H, T. and Lindhe, J. “Dimensions of the Peri-Implant Mucosa; Biological Width Revisited”. Journal of Clinical Periodontology, 1996. Vol. 23, pages 971-973. Herman, J. S, Buser, D., Shenk, R.K., Higginbottom, F.L., and Cochran, D. L. “Biological Width Around Titanium Implants:A Physiologically Formed and Stable Dimension Over Time”. Clinical Implants Res., 2000. Vol. 11, pages 1-11.

Answer 53

Answer: A Rationale: While success rates for mini-implants are high, studies like that of Chang and Tseng demonstrate that implants placed through non-keratinized mucosa have a higher rate of failure. Another factor that may have an adverse affect on success is placement in the posterior mandible. Implant type (mini-screw of mini-plate) does not effect failure rates of rigid orthodontic anchorage. Reference: Chang, S and Tseng, I, International Journal of Oral and Maxillofacial Implants, 2004, Vol. 19, pages 100-106,

Answer 54

Answer: A Rationale: The ability to obtain primary implant stability is associated with the height of the residual alveolar ridge, and is the primary factor related to success when implants are placed in conjunction with osteotome mediated sinus floor elevation. Implant design graft material and method of sinus in-fracture have minimal influence on survival; however, factors such as osteoporosis, type of final prosthesis, and operator experience may also impact the success of this technique. Reference: Toffler, M., “Osteotome Mediated Sinus Floor Elevation: Clinical Report.” International Journal of Oral and Maxillofacial Implants, Vol. 19, No. 2, 2004, pp. 266–273.

Answer 55

Answer: A Rationale: A thick biotype provides greater stability for the peri-implant soft tissues with more predictable healing response following surgery and around restorations. Thin biotypes predispose not only to unpredictable healing but also may allow titanium “show through”. When implant restorative tables are placed more than 5 mm below the contact point of an adjacent tooth, loss of the papilla is common, having an adverse effect on the final aesthetic result. Finally, genetic testing utilizing a swab has identified that positive intraleuken-1 (IL-1) genotype patients have an increased risk of developing periodontitis with enhanced risk of peri-implant complications. Reference: Buser, Martin and Belser, “Optimizing Aesthetics for Implant Restorations in the Anterior Maxilla: Anatomic and Surgical Considerations”, International Journal of Oral and Maxillofacial Implants. Vol. 19, pages 43-61. Tonel, Magner, and Fletcher. “The Effective Distance from the Contact Point to the Crestal Bone on the Presence or Absence of Interproximal Dental Papilla”, Journal of Periodontology, 1992. Vol. 63, pages 995-96 .

Answer 56

Answer: C Rationale: Completion of skeletal height does not correspond to completion of facial growth. A hand- wrist radiograph is inappropriate for assessing facial growth, because it is not specific enough for each patient. The best method of evaluating the completion of facial growth is by superimposing sequential cephalometric radiographs. Most boys do not complete their facial growth until the late teenage years. A 14- or 15-year-old boy may not have gone through his adolescent growth spurt. It is advisable to wait until an adolescent male has completed growth in height. At that point, a cephalometric radiograph should be taken. Another radiograph should be taken at least 6 months to a year later. If these radiographs are superimposed, and there are no changes in vertical facial height (nasion to menton), this indicates that most of the facial growth has been completed. Achievement of Tanner stage V indicates maturity in development of secondary sexual characteristics, but not skeletal maturity. Reference: Kokich V:Orthodontic-restorative management of the adolescent patient. In Orthodontics and Dentofacial Orthopedics, eds McNamara JA Jr. Ann Arbor, MI:=Needham Press; 2001. 425-452. Kokich V:Maxillary lateral incisor implants:=planning with the aid of orthodontics. J Oral Maxillofac Surg. 2004 Sep;62(9 Suppl 2):=48-56. Marshall, W, Tanner, J. Variations in the pattern of pubertal changes in girls. Arch Dis Child 1969; 44:=291 Marshall, W, Tanner, JM. Variations in the pattern of pubertal changes in boys. Arch Dis Child 1970; 45:=13. Law, SJ; Use of Orthopedic appliances in Growth Modification in Fonseca, RJ, Oral and Maxillofacial Surgery Vol 6, Cleft/ Craniofacial/ Cosmetic Surgery, WB Saunders 2000. pp 15-17. Bishara, Facial and dental changes in adolescents and their clinical implications. The Angle orthodontist, 200 Vol 70:=6,p 471

Answer 57

Answer: B Rationale: Contraindications for the use of an implant restoration are in developing patients (particularly in the maxilla, where vertical growth continues after permanent teeth are fully erupted), uncontrolled periodontal disease, aesthetic areas with thin, highly scalloped gingiva, adjacent periapical pathology, and non motivated patients. Relative contraindications where adjacent root flaring precludes placement (correction needed with orthodontics), smokers (increased failure rate especially in type IV bone), connective tissue diseases, and diabetes and autoimmune diseases. Reference: Salinas TJ, Block MS, Sadan A. Fixed partial denture or single-tooth implant restoration? Statistical considerations for sequencing and treatment. J Oral Maxillofac Surg. 2004 Sep;62(9 Suppl 2):2-16. Lindquist LW, Carlsson GE, Jemt T. Association between marginal bone loss around osseointegrated mandibular implants and smoking habits:A 10 year follow- up study J Dent Res 1997;76:1667. De Bruyn H, Collaert B. The effect of smoking on early implant failure Clin Oral Implants Res 1994;5:=260 Isidor F, Brondum K, Hansen HJ. Outcome of treatment with implant-retained dental prostheses in patients with Sjögren syndrome Int J 1999;14:736. Balshi TJ, Wolfinger GJ. Dental implants in the diabetic patient:A retrospective study Implant Dent 1999;8:355 Rajnay ZW, Hochstetter RL. Immediate placement of an endosseous root-form implant in an HIV-positive patient:Report of a case J Periodontol 1998;69:=1167

Answer 58

Answer: A Rationale: The presence or absence of a peri-implant papilla mainly depends on the distance between the alveolar crest and the contact point. In single-tooth gaps, the bone height at adjacent teeth determines the status of the papilla. A clinical study by Dennis Tarnow , et al, demonstrated that a distance of 6mm or more from the alveolar crest to the contact point reduces the probability of intact papillae. Reference: Tarnow DP, Magner AW, Fletcher P. The effect of the distance from the contact point to the crest of bone on the presence or absence of the interproximal dental papilla. J Periodontology 1992;63:995-996

Answer 59

Answer: D Rationale: In soft maxillary bone, preparation of the implant osteotomy site can be completed using a series of osteotomes rather than burs. Because the maxillary bone is soft, an osteotome can be used to split or widen a narrow ridge to receive an implant. In addition, the osteotome condenses and laterally compresses the soft bone at the osteotomy site, placing a denser, compressed bone immediately adjacent to the implant.. Reference: Fonseca, RJ, Oral and Maxillofacial Surgery Vol 7, Reconstructive and Implant Surgery, WB Saunders, 2000, pp 111-114

Answer 60

Answer: C Rationale: In sites with adjacent implants, bone resorption of 1 to 2 mm at the proximal aspects of the implant leads to a flattening of the inter-implant bone and consequently a short inter-implant papilla. A distance of at least 3 mm has been recommended between 2 adjacent implants to minimize this bone resorption. Reference: Tarnow DP, et al. The effect of inter-implant distance on the height of inter-implant bone crest. J Periodontology 2000; 71:=546-549

Answer 61

Answer: B Reference: Hämmerle CHF, et al, Consensus Statements and Recommended Clinical Procedures Regarding the Placement of Implants in Extraction Sockets, Int. J of Oral & Maxillofacial Implants, Vol 19 Supp, pp 26-28

Answer 62

Answer: D Rationale: Soft tissue peri-implantitis occurs most commonly in association with implant supported overdentures, with a reported frequency of 11% to 32%. Rates of soft tissue peri-implantitis associated with implant supported fixed prostheses range from 7% to 20%. Reference: Ardekian, L; Dodson, TB, Complications associated with the placement of dental implants:Oral and Maxillofacial Surg Clin NAm15 (2003) 243-249

Answer 63

Answer: C Rationale: Studies that use insertion torque values are in general agreement that the values should be at least 30 to 35 Ncm." Reference: Ganeles, J, Wismeijer, D:Early and Immediately Restored and Loaded Dental Implants for Single-Tooth and Partial-Arch Applications. The International Journal of Oral and Maxillofacial Implants, Volume 19 Supplement, 2004, page 99.

Answer 64

Answer: A Rationale: The cortical screws for the TMI system are available in lengths of 5,8,11, & 14 mm. Protocol is for the cortical screws to extend beyond the bone for a length of 2mm, but not pierce the periosteum. This allows for tenting of the periosteum and thought to lead to subsequent bone growth. A 3mm mandible is the minimum mandibular height to allow 2mm of “tenting” with the 5mm cortical screw. REFERENCE: Powers MP, Bosker H, Pelt AJW, Dunbar N, “ The Transmandibular implant reconstruction system: From progressive bone loss to controlled bone height. JOMS 1994; 52:904-910. Powers MP, Bosker, H The Transmandibular Reconstruction System in Reconstructive and Preprosthetic Surgery, Fonseca and Davis Editors, Second Edition. WB Saunders Co., 1995. pp 565-668.

Answer 65

Answer: C Rationale: Both techniques allow for maintenance of the attached gingiva. In the closed eruption technique, a crestal incision is made, and a full-thickness flap is reflected. Bone is carefully removed around the crown and a bracket attached. The flap is closed and the tooth is allowed to erupt down through the crestal incision site as traction is placed on the ligature. The referenced study, comparing the two techniques, shows that although the periodontal attachment level was the same in the two techniques, the labially impacted maxillary anterior teeth uncovered w/ apical flap techniques had more unaesthetic scarring, increased clinical crown length, and greater risk of intrusive relapse. The results of treatment with the closed technique were aesthetically superior and there was less relapse. Reference: Beck, RJ, Powers, MP; Soft Tissue Considerations in Fonseca, RJ, Oral and Maxillofacial Surgery Vol 7, Reconstruction and Implant Surgery, WB Saunders 2000. p353. Vermette ME: Uncovering labially impacted teeth: Apically positioned flap and closed reduction techniques. Angle Orthodontics 1995; 65: 23-32

Answer 66

Answer: C Rationale: At the time of third molar extraction, different techniques can be implemented in an attempt to improve the periodontal attachment levels distal to the second molar. A study divided patients undergoing third molar extraction into three different perioperative treatment groups (Guided tissue regeneration (GTR), Demineralized bone powder (DMP), and no special treatment). There were 12 patients in each group. There were no statistical differences between any of the treatment groups in probing depth or attachment level around the second molar. Neither GTR nor DMP techniques showed any advantage over simple healing following third molar extraction Reference: Dodson TB, Management of mandibular third molar extraction sites to prevent periodontal defects. JOMS. 2004 Oct; 62(10): 1213-24.

Answer 67

Answer: D Rationale: The cited study reported the histopathologic diagnoses of a large series of pericoronal lesions in adults submitted to an oral and maxillofacial pathology biopsy service. Of the 2646 lesions submitted, 33% showed demonstrable pathology. The most common pathology was dentigerous cyst (28.4%), followed by OKC (3%), odontoma (0.7%), and ameloblastoma (0.5%). Reference: Curran A, Pathologically significant pericoronal lesions in adults: Histopathologic evaluation. JOMS. 2002 Jun; 60(6): 613-7

Answer 68

Answer: C Rationale: 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. Reference: Dessner, S; Surgical uprighting of second molars: rationale and technique: Oral and Maxillofacial Surg Clin N Am 14 (2002) 201-212. Costello, BJ, Malik, AKB, Powers, MP, Fonseca, RJ; Complicated Exodontia in Fonseca, RJ, Oral and Maxillofacial Surgery Vol 1, Anesthesia/Dentoalveolar Surgery/ Office Management, WB Saunders 2000. p240.

Answer 69

Answer: A 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 require local debridement and definitive treatment consisting of removal of the erupting tooth and/or pericoronal tissues. Antibiotics are not mandatory, and tooth extraction need not to be delayed to complete a course of antibiotics. Reference: Ness, GM, Peterson, LJ; Impacted Teeth in Peterson's Principles of Oral and Maxillofacial Surgery, Miloro, M. et al., Editors, Second Edition, BC Decker Inc, 2004, pp140-142.

Answer 70

Answer: C Rationale: Alveolar osteitis is essentially an inflammation of the bony socket from a recently extracted tooth. Treatment consists of debridement of the socket and placement of a suitable obtundent until the area becomes asymptomatic. Usually no local anesthesia is required. Reference: Ness, GM, Peterson, LJ; Impacted Teeth in Peterson's Principles of Oral and Maxillofacial Surgery, Miloro, M. et al., Editors, Second Edition, BC Decker Inc, 2004, p. 151.

Answer 71

Answer: C Rationale: While somewhat controversial, crowding of mandibular incisor teeth appears to be associated with deficient arch length rather than the mere presence of impacted teeth. After 3rd molar removal the bone height distal to the 2nd molar usually remains at the pre-operative level. Removal of 3rd molars at mandibular advancement osteotomy reduces the thickness and quality of lingual bone at the proximal aspect of the distal segment where fixation screws are usually applied. During a LeFort osteotomy, removal of deeply impacted maxillary 3rd molars from the maxillary sinus side may be done safely without compromising the soft tissue vascular pedicle of the maxilla. Reference: Ness, GM, Peterson, LJ; Impacted Teeth in Peterson's Principles of Oral and Maxillofacial Surgery, Miloro, M. et al., Editors, Second Edition, BC Decker Inc, 2004, pp. 140-153.

Answer 72

Answer: C Rationale: The mandibular 3rd molar, visible radiographically as a tooth germ usually by age 9 within the anterior border of the ramus, progresses with mandibular growth to the body due to resorption of the anterior border of the ramus. The tooth's anterior facing occlusal surface changes orientation to vertical, usually by age 20, during its root development. The failure to progress to final vertical orientation may be attributed to one or more factors including: Over or under development of the mesial and/or distal roots Insufficient arch length to accommodate the normal position of the tooth within the arch Reference: Ness, GM, Peterson, LJ; Impacted Teeth in Peterson's Principles of Oral and Maxillofacial Surgery, Miloro, M. et al., Editors, Second Edition, BC Decker Inc, 2004, pp. 139-140

Answer 73

Answer: B Rationale: The usage of prophylactic antibiotics involves the issue of risk versus benefits. Without further extenuating conditions, the increase of antibiotic-related complications, e.g. allergy, resistant bacteria, gastrointestinal side effects, and secondary infections, is not outweighed by the benefits in an otherwise uncomplicated 3rd molar surgery. Perioperative steroids do have a major clinical impact on swelling in the early postoperative period but, for maximum control, additional steroids must be given for 1 or 2 days following surgery. The administration of perioperative steroids may increase the incidence of alveolar osteitis after third molar surgery, the data are lacking as to the precise degree of increase. Reference: Ness, GM, Peterson, LJ; Impacted Teeth in Peterson's Principles of Oral and Maxillofacial Surgery, Miloro, M. et al., Editors, Second Edition, BC Decker Inc, 2004, pp 147-149.

Answer 74

Answer: D Rationale: This is an axial scan of a pterygomandibular space abscess. The scan reveals a radiolucent, contrast-enhancing collection between the ascending ramus of the mandible and distended medial pterygoid muscle. The lateral pharyngeal space and airway are distorted by mass effect and edema. The borders of the pterygomandibular space are the ascending ramus of the mandible laterally, the medial pterygoid muscle medially, the pterygomasseteric sling inferiorly, and the lateral pterygoid muscle superiorly. The parotid gland and capsule form the posterior border. The pterygomandibular raphe is the anterior border. REFERENCE: Flynn , TR In Topazian , RG, Goldberg, MH, Hupp, JR, editors: Oral and Maxillofacial Infections, ed 4, Philadelphia, 2002, W B Saunders Co., pp 188-213.

Answer 75

Answer: B Rationale: The donor third molar roots should be no less than half and preferably about two thirds developed. Reference: Silva, RG, Pogrel, MA; Tooth Reimplantation and Transplantation in Fonseca, RJ, Oral and Maxillofacial Surgery Vol 1, Anesthesia/Dentoalveolar Surgery/ Office Management, WB Saunders 2000. pp 299-301. Kaban, LB, Dentoalveolar Surgery in Kaban Pediatric Oral and Maxillofacial Surgery, WB Saunders, 1990, p109.

Answer 76

Answer: D Rationale: The tooth clearly is not in the maxillary sinus. Additionally is not in the pterygomaxillary fissure between the pterygoid plate and posterior maxilla. The level of the scan is below the superficial temporal space, the inferior boundary of which is the zygomatic arch. The tooth resides in the infratemporal space. The infratemporal space is the portion of the deep temporal space that lies inferior to the infratemporal crest of the sphenoid bone. The inferior border is the superior surface of the lateral pterygoid muscle. The anterior border of the deep temporal space is composed of the posterior wall of the maxillary sinus, the pterygomaxillary fissure, and the posterior surface of the orbit, including the inferior orbital fissure. Reference: Flynn, TR In Topazian, RG, Goldberg, MH, Hupp, JR, editors: Oral and Maxillofacial Infections, ed 4, Philadelphia, 2002, W B Saunders Co., pp 200-203.

Answer 77

Answer: B Rationale: Mitral valve prolapse is a common condition affecting 2%-5% of the population. It likely is inherited as an autosomal dominant trait, and is more common in women. The murmur associated with mitral valve prolapse occurs late in systole and is not affected by respiration. MVP is associated with ventricular premature beats, paroxysmal atrial tachycardia, atrial fibrillation, Von Willebrand's syndrome, polycystic kidney disease, atrial secundum defects and Marfan's syndrome. Reference: LeBlond R, DeGowin R, Brown D:DeGowin's Diagnostic Examination 8th ed., McGraw-Hill, New York, 2004, pp.428-429. Sdrales L, Miller R:Anesthesia Review., Churchill Livingstone, Philadelphia, 2001, pp.268-269.

Answer 78

Answer: C Rationale: Sustained elevated blood pressure can lead to left ventricular failure, pulmonary edema, myocardial ischemia, and cardiac dysrhythmias. Antihypertensive agents must be chosen carefully when a patient with a history of ischemic heart disease is being treated. Labetalol is a selective Alpha, and nonselective Beta-blocker. Reflex tachycardia is not seen after administration and cardiac output is not changed. Pulmonary artery and wedge pressures decrease. Esmolol is a rapid acting cardioselective beta blocker which does not increase cardiac output or cardiac oxygen consumption. Oral clonidine is a centrally acting alpha agonist with a wide margin of safety. Hydralazine is a parenteral antihypertensive that acts as a direct vasodilator., and may result in unopposed beta stimulation with significant reflex increases in cardiac output. Hydralazine is contraindicated when a patient has a history of ischemic heart disease. Reference: Crawford M:Current Diagnosis & Treatment in Cardiology., Lange Medical Books/McGraw- Hill, New York, 2003, pp.176-178. Ogle O, ed:Oral and Maxillofacial Surgery Clinics of North America., W.B. Saunders, Philadelphia, 1998, Vol 10, No.3, pp.349-361.

Answer 79

Answer: D Rationale: Chronic alcoholism and malnutrition is frequently associated with hypomagnesemia which can provoke a polymorphic ventricular tachycardia, torsades de pointe, with a prolonged QT interval. The immediate treatment is to administer magnesium. Epinephrine may increase myocardial irritability and worsen the tachycarida. Amiodarone prolongs the QT interval which can cause a worsening of the torsades. Lidocaine may be given but is not as efficacious as magnesium for this type of arrhythmia. If available, overdrive pacing is an acceptable alternative to magnesium. Reference: Cummins:Case 3. ACLS Provider Manual:75-95, 2001

Answer 80

Answer: C Rationale: Dysfunction is found in most organ systems in the severely malnourished patient, but the most dangerous are fluid/electrolyte disorders. Amongst the answers given, a determination of electrolyte status would be the most appropriate in this situation. Other pertinent pre-op tests would include an electrocardiogram and complete blood count. Metabolic alkalosis, hypocalemia, and hypokalemia may manifest with prolongation of the QT interval. Sudden death in these individuals is often precipitated by ventricular arrhythmias. AST, GGT, ALT and alkaline phosphatase are blood screening tests for hepatic function. Although anorexia may affect the hepatobiliary system, cardiac function associated with anorexia would have the greatest potential impact in safely managing this patient. A 24 hour urine measuring the levels of metanephrines would be an appropriate study in the differential diagnostic work up for an adrenal neoplasm (such as a pheochromocytoma). This study will not yield any data that would assist in the diagnosis or management of anorexia nervosa. Although Prothrombin time (PT) and Partial Thromboplastin Time may be prolonged secondary to liver disease, these are not usually associated with anorexia. Fibrin degradation products are associated with disseminated intravascular coagulopathy (DIC), not with anorexia. Reference: The Merck Manual, 17th Ed., Merck and Co., 1999, pp.1595-6. 2002 Ferri's Clinical Advisor, Fred Ferri, Mosby 2002 Edition, pp. 66-7.

Answer 81

Answer: D Rationale: Patients with stress-induced symptoms of ischemia usually provide the best assessment of risk for adverse events from CAD. Ischemic tendencies would be evidenced by the presence of ST depression or inverted T waves. The addition of cardiac imaging increases the sensitivity of the stress test, especially when resting ECG abnormalities exist or conditions are present that may cause abnormal stress-induced ECG changes not secondary to ischemia. Excessively tall QRS complexes may indicate ventricular hypertrophy. Prolonged P-R intervals indicate conduction delay at a location between the atria and the ventricles (such as at the A-V node.) Biphasic P waves are indicative of atrial hypertrophy. Reference: OMS Knowledge Update; Vol. I, Part II, 1995, p PEV21. Peterson LJ, Indresano AT, Marciani RD, Roser SM, Principles of Oral and Maxillofacial Surgery; 1992, Chapter 2, p 20.

Answer 82

Answer: C Rationale: Aortic stenosis is the most common congenital cardiac abnormality. Patients typically present with angina, syncope and congestive heart failure. The classic murmur of aortic stenosis is a harsh systolic ejection murmur. The only effective treatment is valve replacement. Aortic regurgitation is associated with a high pitched diastolic decrescendo murmur. Mitral stenosis auscultation yields a diastolic rumble, loud S1, and an opening snap. Mitral regurgitation creates a holosystolic murmur with radiation to the axilla. Reference: Crawford M:Current Diagnosis & Treatment in Cardiology., Lange Medical Books/McGraw- Hill, New York, 2003, pp.108-117. Andreoli T:Cecil Essentials of Medicine., W.B. Saunders, Philadelphia, 2004, pp.78-80.

Answer 83

Answer: C Rationale: Insufficiency of the tricuspid valve initially produces a volume overload to the right atrium and ventricle, which dilate as a compensatory mechanism. This gives rise to elevated central venous pressures which cause right sided “congestive failure.” If the tricuspid regurgitation is massive, under-filling of the left heart can result.(this last sentence need a little work) Reference: Luce J, Pierson D (Eds.):Critical Care Medicine, 1988,WB Saunders, p. 47.

Answer 84

Answer: C Rationale: IHSS is usually an inherited autosomal dominant characteristic, and can be associated with long term hypertension. Depending on the area of hypertrophy, the systolic left ventricular outflow can be significantly obstructed during systole. Fatal dysrhythmias and sudden death may result even in healthy teenagers with undiagnosed hypertrophy. Reference: Peterson's Principles of Oral and Maxillofacial Surgery, Second Edition, Vol I pg 69

Answer 85

Answer: D Rationale: One liter of 5% dextrose in water yields 50 g of dextrose; with available calories:4 kcal/gm, or 200 kcal. O.9% (normal) saline has an osmolality of 308; while lactated Ringer's solution is 273. Obligate renal potassium losses are about 40 mEq/day, and requires replacement (either from oral intake or by a parenteral supplement.) Ringer's lactate has no magnesium hence no possibility of hypermagnesemia. Reference: Washington University Manual of Medical Therapeutics (30th ed.), pp43-45

Answer 86

Answer: B Rationale: During normal embryonic cardiogenesis, strands of electroconductive tissue form connections between the atria and ventricles outside of the normal conduction pathway. These strands normally become non-functional shortly after birth. In WPW, persisant connections via extranodal pathways bypass part of all of the normal conduction system and function in a re-entry capacity. In WPW the accessory pathway is called the Kent Bundle and connects the atria directly to the ventricles and is a cause of atrial fibrillation. This can result in a ventricular rate of 250-300 beats/min. Treatment of WPW, especially if atrial fibrillation is present, with IV verapamil may decrease the accessory pathway refractory period, increasing the ventricular rate and potentiating ventricular fibrillation. Radiofrequency ablation has become one of the procedures of choice in ablating the accessory conductive pathways in WPW syndrome. Reference: ACLS Quick Review Study Guide, Second Ed. Barbara Aehlert, RN pg 180 Mosby.

Answer 87

``` Answer: C Rationale: Unstable angina is a pre-infarctive condition, in which the developing thrombus is platelet rich and where antiplatelet drugs are indicated. ST depression with lack of Q waves and positive cardiac troponin indicate an early or intermittent infarction (termed a non-Q-wave myocardial infarction.) The thrombus at this stage is a mixture of a fibrin clot and platelets; and treatment at this time with a thrombolytic may liberate clot-bound thrombin, enlarging or embolizing the clot and may paradoxically worsen coronary occlusion. Q wave MIs indicate total thrombotic occlusion and are an indication for prompt coronary angioplasty. Heparin is commonly used with both fibrin specific thrombolytics and with angioplasty procedures. Reference: ACLS Provider Manual (2001), pp123-127 ```

Answer 88

Answer: C Rationale: Mitral stenosis is associated with diminished pulse pressure as there may be impaired left ventricular filling. A triad of symptoms associated with MS includes left atrial hypertrophy, pulmonary hypertension and right ventricular hypertrophy due to stenosis of the mitral valve. This condition requires the cardiac structures upstream from the mitral valve to overcome increased resistance across a stenotic mitral valve resulting in hypertrophic changes in those areas. Note: pulmonary hypertension is the result of smooth muscle hypertrophy involving the pulmonary arteriolar bed. Reference: McCabe, Roser: Evaluation and management of the cardiac patient for surgery. Oral Max Surg Clin of N Amer 10:3, 1998. Ramadan, et al: Preoperative evaluation of cardiac risk. Adv Surg 28: 1995

Answer 89

Answer: A Rationale: All patients with bicuspid aortic valves --- even those with no significant stenosis or regurgitation --- should be given antibiotic prophylaxis for bacterial endocarditis for surgeries involving the aerodigestive tract. As much as 2% of the population has congenitally bicuspid aortic valves. A bicuspid aortic valve may present as an incidental finding on physical examination or echocardiography done for other reasons. On physical examination, the cardinal sign of a bicuspid aortic valve is an early systolic ejection click. If no significant hemodynamic abnormality is present, either no murmur or a soft ejection murmur may be heard; a very mild murmur of aortic regurgitation (AR) is not uncommon, even with hemodynamically insignificant bicuspid aortic valves. Aortic stenosis (AS) or AR from any other cause will produce similar findings. Both the presence of a bicuspid aortic valve and its hemodynamic significance can be determined by echocardiography. Serial studies are useful in following the progression of the lesion.. Patients with AR from a bicuspid valve who are asymptomatic and have normal systolic function are followed with echocardiograms and physical examinations at regular intervals. If they begin to show decreasing systolic function, symptoms of heart failure, or progressive dilation of the left ventricle, surgical replacement of the aortic valve is indicated. Reference: Harrison's Principles of Internal Medicine 14th ed, p. 1320

Answer 90

Answer: A Rationale: Sarcoidosis is a multisystem granulomatous disease. Respiratory manifestations include laryngeal granulomas or nodules as well as intrathoracic nodes that may compress or distort the airway. Involvement of the recurrent laryngeal nerve can cause unilateral vocal cord paralysis. Obstruction of the lower airways can result in atelectasis, but local obstruction is not the same as obstructive lung diseases. Sarcoidosis is a restrictive lung disease, with the majority of pulmonary damage occurring in the parenchyma. Patients may be prescribed steroids and perioperative care must ensure appropriate steroid coverage. Pulmonary fibrosis seen in advanced stages of the disease and may result in a pneumothorax. Patients generally take rapid shallow breaths to compensate for the physiologic changes. Hypoxemia is common at rest in severe disease. Reference: Kinney MAO, Harrison BA, Ruyter MLD: Sarcoidosis in Complications in Anesthesia Eds Altee JL. WB Saunders 1999

Answer 91

Answer: B Rationale: Asthma diagnosis rests upon the measurement of peak expiratory flow rates (spirometry) before and after administration of an inhaled beta adrenergic agonist; the reversibility of lowered expiratory flows being diagnostic for this disorder. Alterations in plane chest radiographs, arterial blood gases, and in auscultation of the chest by stethoscope may occur with asthma, but changes in these are not specific for the diagnosis of asthma. Reference: Little JW, Falace DA et al: Dental Management of the Medically Compromised Patient 6th ed. . St. Louis, Mosby, 2002 p. 132. Harrison's Principles of Internal Medicine 14th ed. New York, McGraw-Hill, 1997 p. 1423

Answer 92

Answer: B Rationale: Patients who have had a laryngospasm may be susceptible to secondary pulmonary edema. This can be the result of negative alveolar pressure of an expanding diaphragm against a closed glottis, or due to barotrauma from positive pressure ventilation. Pulmonary trauma arising from laryngospasm may become clinically evident hours after the spasm. In this case, signs arising immediately after the treated laryngospasm may indicate imminent pulmonary failure which may require endotracheal intubation and airway support using positive end expiratory pressure, and possibly diuretics. While this patient may have had an aspiration, the management of this complication would not be alkalinization of the airways. It is unlikely that the acute onset of dyspnea in this case was due to pleural effusion or pneumonia Reference: Brandom BW. Pulmonary Edema After Airway Obstruction. International Anesthesiology Clinics 35(3):75-84, 1997. Halow KD, Ford EG. Pulmonary Edema following Post-operative Laryngospasm:A Case Report and Review of the Literature. American Surgeon 59(7):=443- 447, 1993.

Answer 93

Answer: D Rationale: Chronic obstructive lung disease encompasses chronic obstructive bronchitis and emphysema. With both disorders, FEV/ FVC is decreased; but residual volume, functional residual capacity and tidal volume are generally increased. Chronic obstructive bronchitis is referred to as “blue bloater”. The disease is characterized by obstruction of small airways secondary to mucus and inflammation. Patients with chronic bronchitis have significant decreases in PaO2 (< 65 mmHg is typical.) Compensatory consequences include erythrocytosis. PaCO2 is also chronically elevated. This results in pulmonary hypertension and cor pulmonale. Physiologic changes found with emphysema include destruction of lung parenchyma, enlargement of airway spaces, loss of lung elasticity and closure of small airways. Rapid, shallow respirations generally result in a PaCO2 which is normal to slightly decreased and a PaO2 > 65 mmHg. This disease is categorized as “pink puffer” and is generally not associated with cor pulmonale. Reference: Stoelting RK & Dierdorff SF: Handbook for Anesthesia and Co-Existing Disease. 2nd edition Churchill Livingston 2002

Answer 94

Answer: D Rationale: The diagnosis of pulmonary thromboembolism can be difficult, and the results of clinical, laboratory, and radiologic exams can be equivocal. Testing is generally based upon risk stratification (according to clinical presentation, medical history, surgical procedures, and other risk factors both for developing PE and for risks of this disorder.) The most common suspected site of origin for pulmonary thrombi are from deep leg veins; so in the case of suspected but unconfirmed PE, repeat serial leg vein ultrasound is indicated. ELISA tests vary in sensitivity the d-dimer breakdown products from thrombi; with the results generally not immediately available. Venous contrast helical CT is being advocated as a screening tool for PE, but this modality has not proven to be highly sensitive or specific for (small) subsegmental PE's, which are notoriously difficult to diagnose. Decreased in left ventricular output are an ominous sign in PE, caused by decreased left atrial filling. Fluid bolus therapy in these patients, who already are in right heart failure, is contraindicated. Reference: Kearon C: Diagnosis of pulmonary embolism. J. Can. Med Assoc, 168:2, Jan 2003 Goldhaber S: Pulmonary thromboembolism. In: Fauci et al (eds;) Harrison's Principles of Internal Medicine 14th ed. p. 1468

Answer 95

Answer: B Rationale: Leukotrienes are potent biochemical mediators that are released from mast cells, eosinophils, and basophils. Leukotrienes work to contract airway smooth muscle, increase vascular permeability and mucus secretions, and attract and activate inflammatory cells in the airways of patients with asthma. They are produced by the oxidation of arachidonic acid through the enzyme lipoxygenase. The action of leukotrienes can be blocked through either of two specific mechanisms: 1) inhibition of leukotriene production and, 2) antagonism of leukotriene binding to cellular receptors. The FDA has approved three products thus far. Zafirlukast and montelukast are both selective and competitive leukotriene receptor antagonists of leukotriene D and E. These are components of slow-reacting substance of anaphylaxis. Zileuton, a specific inhibitor of 5-lipooxygenase, inhibits leukotriene formation, especially LTB1, LTC1, LTD1, LTE1. As a leukotriene antagonist, SingulairR (montelukast) has no effect on lipoxygenase or arachidonic acid function. Arachidonic acid is produced by membrane phospholipids through the enzyme phospholipase A2 which is blocked by corticosteroids. Cyclooxygenase inhibitors (i.e. NSAIDs, COX inhibitors) block the production of prostaglandins. Beta-2 stimulation results in bronchodilation and is the main mechanism of medications such as albuterol and not the leukotriene inhibitors. Reference: Kastrup EK, et al. (eds) Respiratory drugs. In Drug Facts and Comparisons, 1998. St. Louis, Facts and Comparisons. Pp 1133-1140. Aharony D. Pharmacology of leukotriene receptor antagonists. Am J Respir Crit Care Med 1998;157:S214-9.

Answer 96

Answer: A Rationale: The diffusion capacity of the lungs for any gas is dependent upon the diffusion coefficient (for the gas in question), the surface area and thickness of the alveolar-capillary membrane, and the partial pressure gradient across the barrier. Changes in any of these variables will affect the diffusing capacity. The alveolar –capillary membrane is made up of various layers. These layers traveling from the alveolus toward the capillary are: surfactant layer, alveolar epithelium, interstitial space, pulmonary capillary endothelium, plasma, and red blood cell. On average, this barrier is about 0.5 μm in thickness. Alveolar edema or exudates such as in acute respiratory distress syndrome increases the thickness of the blood-gas barrier in the lung, which increases the time necessary for equilibration of CO2 and O2 across the blood- gas barrier. Diaphragmatic paralysis will inhibit air exchange but not the ability to equilibrate gaseous exchange across the alveolar/capillary surface. A pleural effusion and chylothorax are is present in the pleural space and therefore will not directly affect the diffusion of gases in the alveoli of the lung. Reference: Vander AJ, Sherman JH, Luciano DS: Respiration In Human Physiology: The Mechanisms of Body Function, , 4th edition, 1985. Pocock, G. & Richards, C.D. – Human Physiology: the Basis of Medicine, Oxford Core Texts, 1st Edition, 1999

Answer 97

Answer: D Rationale: Nasopharyngoscopy , especially supine and using Mueller's Maneuver (holding the nose and mouth closed against forced inspiration) is the most useful to diagnose the level of airway obstruction in the sleep apnea patient. A Fujita Type II airway obstruction occurs at both the retropalatal (oropharyngeal) and retrolingual (hypopharyngeal) areas; while a Type I is retropalatal and Type III is retrolingual. Polysomnography establishes the diagnosis of obstructive sleep apnea but not the location of obstruction. The Epworth Sleep Scale is a subjective evaluation of daytime hypersomnolence and is useful in the referral of patients for further sleep disorder work up. The interview of a bed partner, especially as to sonorous breathing, loud snoring, or observed obstructive apneas is highly sensitive for the presence of obstructive sleep apnea and should prompt the practitioner to further sleep disorder work up including polysomnography. Reference: Bond T: Evaluation and diagnosis of sleep-disordered breathing. OMS Clinics N America14:3, 293-296 Aug 2002

Answer 98

Answer: D Rationale: The sources of asthmatic airway processes are rapid release of chemical mediators, abnormalities of airway neuroregulation, or an intrinsic defect of airway smooth muscle. Ten percent of patients with asthma can experience bronchial constriction and rhinorrhea in response to aspirin or NSAIDs such as prioxicam. The mechanism is via blockade of prostaglandin synthesis, causing leukotriene build up. Methohexital may be epileptogenic (unlike other barbiturates); and histamine release by methohexital or morphine may also precipitate an asthma attack. Ketamine acts as a bronchidilator and does not possess epileptogenic properties. Reference: Little J, Falace D: Dental Management of the Medically Compromised Patient 6th ed., Mosby, St. Louis 2002, P 136. Malamed S: Sedation: A Guide to Patient Management 4th ed, Mosby, St. Louis, 2003, pp 560-561. Ruggiero S: Evaluation, Treatment, and Management of the Asthmatic Patient, Oral and Maxillofacial Surgery Clinics of North America, WB Saunders, Philadelphia, 10:3 Aug 1998, pp339-343

Answer 99

Answer: B Rationale: Cystic fibrosis is an autosomal recessive inherited disease of the exocrine glands, primarily affecting the GI and respiratory systems, and usually characterized by COPD, exocrine pancreatic insufficiency, and abnormally high sweat electrolytes (particularly chloride > 60 mEq/L). In addition to thickened sputum and pancreatic enzyme dysfunction, males often have azospermia secondary to obstruction of the vas deferens by thickened secretions. Reference: Facts About Cystic Fibrosis, Cystic Fibrosis Foundation, Bethesda, MD, November 16, 2001. Farrell, P.M., et al. Early diagnosis of cystic fibrosis through neonatal screening prevents severe malnutrition and improves long-term growth. Pediatrics, volume 107, number 1, January 2001, pages 1-13.

Answer 100

Answer: D Rationale: Theophylline, a thioxanthine, acts centrally as an indirect adrenergic, causing dilation of bronchial smooth muscle and is used in the management of refractory asthma. Toxicity is manifested as hyperadrenergia including tachycardia, hypertension, and hyperreflexia. Erythromycin reversibly inhibits hepatic degradation of theophylline and can lead to toxic serum levels of the bronchodilator. The same is true with concomitant use of theophylline with cimetidine, ciprofloxacin, and allopurinol. Clindamycin, cephalexin, and penicillin do not diminish theophylline metabolism. Reference: Abubaker AO, Benson KJ: Oral and Maxillofacial Surgery Secrets, Philadelphia, Hanley & Belfus, 2001 P. 122

Answer 101

Answer: B Rationale: A number of factors play a role in controlling alveolar ventilation. The central areas of inspiratory and expiratory control lie in the medulla, and primarily respond to increases in hydrogen ion concentration in the cerebrospinal fluid. Although hydrogen ion concentration is the most important stimulus to the chemosensitive centers in the medulla, these ions cross from blood through the blood-brain barrier to cerebrospinal fluid with difficulty. In contrast, CO2 readily crosses the blood-brain barrier to react with water to form carbonic acid in the CSF, which dissociates to provide the required hydrogen ion necessary for stimulation. Peripheral chemoreceptors transmit signals via cranial nerves ten (to the aortic bodies) and nine (to the carotid bodies) to the inspiratory area of the medulla and pons. These signals help control breathing frequency and lung inflation. The peripheral receptors respond to drops in arterial oxygen pressure. Generally speaking, carbon dioxide pressure plays a much greater influence on ventilation than oxygen pressure. To exemplify the role that the PaCO2 plays in controlling alveolar ventilation, a 50% increase in arterial PaCO2 produces a tenfold increase in alveolar ventilation, while a 40mmHg decrease in arterial PaO yields only a 1.5 fold increase in alveolar ventilation. The high blood flow through the richly vascularized peripheral chemoreceptors allows the needs of the receptors to be almost entirely met by dissolved oxygen, and excess oxygen bound as oxyhemoglobin is not used by the receptors. As a result, the PaO2 determines the level of peripheral receptor stimulation rather than the arterial oxygen saturation (SaO2). Reference: Stoelting R: Pharmacology and Physiology in Anesthetic Practice 3rd ed., Lippincott, Williams, and Wilkins, New York, 2001, pp 726-728. Morgan G, Maged S, Clinical Anesthesiology 2nd ed., Lange Medical Books, New York, 1996, pp436-437.

Answer 102

Answer: C Rationale: Cerebral perfusion pressure is calculated by the following formulae: Mean arterial pressure: diastolic blood BP + 1/3 (systolic BP – diastolic BP) 140 + 1/3 (220-140) 167 Cerebral perfusion pressure (CPP): Mean arterial pressure-Intracranial pressure (ICP) 167 – 40 127 (about 130) Cerebral blood flow is constant when CPP is maintained between 50-150mmHg. To maintain cerebral blood flow, the MAP should be between 60-160mmHg and the ICP between 5- 15mmHg. As the ICP begins to rise, cerebral autoregulation occurs increasing cerebral vascular resistance causing cerebral hypertension in an attempt to maintain cerebral blood flow. Reference: Cushing H. The blood pressure reaction of acute cerebral compression, illustrated by cases of intracranial hemorrhage. Am J Med Sci:125, 1017-1044, 1903

Answer 103

Answer: A Rationale: Myasthenia gravis is an acquired autoimmune disorder affecting transmission at neuromuscular junction. It is an autosomal dominant condition. 80-90% of patients will have auto antibodies to the acetylcholine receptors of the post synaptic membrane. Patients exhibit prolonged neuromuscular blockade to non-depolarizing muscle relaxants; but usually show some resistance to the muscle paralysis of succinylcholine. When MG is suspected the first test that may be performed is the Tensilon test using edrophonium 2mg IV wait 30 seconds for effect, assess for improvement in muscle strength that lasts for 5minutes. Repeated doses of 8mg may be given. If this test is positive supportive care is required until the neuromuscular blockade improves. In a myesthenic crisis plasmapheresis may be indicated for temporary relief, but not as first line measure. Head CT would not be the first line diagnostic test in an awake patient who has a nonfocal neurologic examination. Electromyography and muscle biopsy can be used as definite test for MG. Pyridostigmine is used for treatment of MG, and not usually for diagnosis due to its slower onset and longer duration of action. Reference: Sanders DB. Myasthenia Gravis and Myasthenic syndrome. Philadelphia, 1994. Drachman DB. Myasthenia gravis; medical progress. N Eng J Medicine 330, 1797, 1994

Answer 104

Answer: B Rationale: Absence seizures have cessation of conscious activity without any convulsions or loss of postural control. These tend to be very brief, lasting seconds to sometimes a few minutes, and are usually diagnosed in young children. The EEG is pathognomonic and often shows that the child is having many more seizures than was evident. Antiepileptic drugs usually are effective for treatment. Reference: Wilson, JD ed. Harrison's Principles of Internal Medicine. McGraw-Hill, Inc. 1991. p. 1969.

Answer 105

Answer: C Rationale: Because the facial nerve has so many functions and is so complex, damage to the nerve or a disruption in its function can lead to many problems. Symptoms of Bell's palsy, which vary from person to person and range in severity from mild weakness to total paralysis, may include twitching, weakness, or paralysis on one or both sides of the face, drooping of the eyelid and corner of the mouth, drooling, dryness of the eye or mouth, impairment of taste, and excessive tearing in one eye. These symptoms usually begin suddenly and reach their peak within 48 hours. Other symptoms may include pain or discomfort around the jaw and behind the ear, ringing in one or both ears, headache, loss of taste, hypersensitivity to sound on the affected side, impaired speech, dizziness, and difficulty eating or drinking. Palsy occurs when the nerve that controls the facial muscles is swollen, inflamed, or compressed, resulting in facial weakness or paralysis. Exactly what causes this damage, however, is unknown. Most scientists believe that a viral infection such as viral meningitis or the common cold sore virus - herpes simplex - causes the disorder. Bell's palsy afflicts approximately 40,000 Americans each year. It affects men and women equally and can occur at any age, but it is less common before age 15 or after age 60. It disproportionately attacks pregnant women and people who have diabetes or upper respiratory ailments such as the flu or a cold. There is no cure or standard course of treatment for Bell's palsy. The most important factor in treatment is to eliminate the source of the nerve damage. Bell's palsy affects each individual differently. Some cases are mild and do not require treatment as the symptoms usually subside on their own within 2 weeks. For others, treatment may include medications and other therapeutic options. Recent studies have shown that steroids are an effective treatment for Bell's palsy and that an antiviral drug such as acyclovir- used to fight viral infections-combined with an anti-inflammatory drug such as the steroid prednisone-used to reduce inflammation and swelling-may be effective in improving facial function by limiting or reducing damage to the nerve. Analgesics such as aspirin, acetaminophen, or ibuprofen may relieve pain. Another important factor in treatment is eye protection. Bell's palsy can interrupt the eyelid's natural blinking ability, leaving the eye exposed to irritation and drying. Therefore, keeping the eye moist and protecting the eye from debris and injury, especially at night, is important. Lubricating eye drops, such as artificial tears or eye ointments or gels, and eye patches are also effective. Facial massage and exercises may help prevent permanent contractures (shrinkage or shortening of muscles) of the paralyzed muscles before recovery takes place. Moist heat applied to the affected side of the face may help reduce pain. Other therapies that may be useful for some individuals include relaxation techniques, acupuncture, electrical stimulation, biofeedback training, and vitamin therapy (including vitamin B12, B6, and zinc), which may help nerve growth. A diagnosis of Bell's palsy is made based on clinical presentation-including a distorted facial appearance and the inability to move muscles on the affected side of the face-and by ruling out other possible causes of facial paralysis. There is no specific laboratory test to confirm diagnosis of the disorder. Generally, a physician will examine the individual for upper and lower facial weakness. In most cases this weakness is limited to one side of the face or occasionally to the forehead, eyelid, or mouth. A test called electromyography (EMG) can confirm the presence of nerve damage and determine the severity and the extent of nerve involvement. An x-ray of the skull can help rule out infection or tumor. A magnetic resonance imaging (MRI) or computed tomography (CT) scan can eliminate other causes of pressure on the facial nerve. Reference: Fauci JD et al (Eds.): Harrison's Principles of Internal Medicine 14th Ed,.McGraw-Hill, New York, 1998 pp2378-9

Answer 106

Answer: D Rationale: A Rinne test involves evaluating a subject's ability to hear a vibrating tuning fork when it is held next to the ear and when it is placed on the mastoid process. Normally, air conduction is greater than bone conduction. A positive Rinne test exhibits diminished hearing acuity through air and somewhat heightened hearing acuity through bone, and is symptomatic of conduction deafness. Testing for damage to cranial nerve VIII vestibular function (such as cold water irrigation of the external auditory canal) often reveals nystagmus and for cochlear function reveals hearing loss. Therefore, a patient with VIII nerve disruption would have neither bone nor air conductive hearing. Injury to the facial nerve would be manifest by loss of facial animation and loss of taste on the involved side. Reference: Handler, BH. History and Physical examination in PH Kwon, Daniel Laskin. Clinicians Manual of Oral and Maxillofacial Surgery, 2nd edition. Quintessence Publishing, Chicago. Chapter 1, Page 7

Answer 107

Answer: B Rationale: Muscular dystrophy (MD) has historically been diagnosed and categorized based on the age of onset, affected muscle groups, and genetic inheritance. Nearly one-third of new cases are spontaneous mutations, but two-thirds are inherited. Duchenne's is by far the most common form of MD and is due to abnormal and deficient dystrophin; other forms of MD may involve other myocyte proteins. Administration of a depolarizing muscle relaxant to a patient with MD would be likely to cause a massive potassium release that could precipitate cardiac arrest due to hyperkalemia. MD patients, especially those with Duschenne's type, are susceptible to malignant hyperthermia and therefore the use of triggering agents such as depolarizing muscle relaxants (succinylcholine) and halogenated potent volatile anesthetics should be avoided. A nitrous oxide/opioid (“nitrous/narcotic”) anesthetic technique would be appropriate for such a patient. Prolonged muscle paralysis with succinylcholine is typical of a cholinesterase deficiency, not muscular dystrophy. These patients also have delayed gastric emptying time, with the associated risk of aspiration if the airway is not adequately protected. Demise from MD usually occurs in the 20's from respiratory failure. Reference: Goldman:Cecil Textbook of Medicine, 22nd ed., Copyright 2004 W. B. Saunders Company, pp. 2387-2391

Answer 108

Answer: A Rationale: Carbamazepine is the treatment of choice for trigeminal neuralgia. This anticonvulsant provides relief to greater than 75% of trigeminal neuralgia patients. However, potential life- threatening side effects include agranulocytosis, aplastic anemia, or thrombocytopenia. Changes in levels of serum electrolyte levels, clotting factors/profactorslevels, or calcium/phosphate are not generally thought to be within the side effect or complication profile of carbamazepine. Reference: 2002 Ferri's Clinical Advisor, Fred Ferri, Mosby 2002 Edition, p. 717. Oral and Maxillofacial Pathology, Neville et. al., W.B. Saunders, 1995, pp. 628-9.

Answer 109

Answer: B Rationale: Myasthenia gravis is an autoimmune disorder that occurs 1/20,000 persons and is characterized by injury of the acetylcholine receptors at the postsynaptic neuromuscular junction. These patients exhibit marked sensitivity to nondepolarizing muscle relaxants and slight resistance to succinylcholine Reference: Clinical Anesthesia Procedures of the Massachusetts General Hospital, 4th Ed., Davidson, et.al., Little Brown, 1993, pp. 166-8.

Answer 110

Answer: D Rationale: This complex regional pain syndrome typically occurs after a relatively minor injury resulting in a persistent, burning sensation with hyperesthesia and hyperpathia. This is thought to occur from a heightened sympathetic outflow. Peripheral vasodilation (skin flushing and warmth) or vasoconstriction (skin pallor and coolness) may occur. Diagnosis and treatment depend on pain relief following sympathetic blockade. Reference: Clinical Anesthesia Procedures of the Massachusetts General Hospital, 4th Ed., Davidson, et.al., Little Brown, 1993, pp. 595-6. Handbook of Neurosurgery, 2nd Ed., Greenberg, M., Greenberg Graphics, Inc., 1991, pp. 328-9. The Merck Manual, 17th Ed., Merck and Co., 1999, pp. 1372-3.

Answer 111

Answer: C Rationale: Temporal arteritis is a chronic inflammatory disease involving large arteries of the carotid system, particularly in those with a prominent elastica, occurring primarily in the elderly. This disorder commonly causes pain on mastication in the masseter, temporals, and tongue muscles. Estimated prevalence is about 1/1000 in patients > 50 yo with a slight predilection in females. Symptoms typically include a severe headache, scalp tenderness, and visual disturbances. It can cause blindness secondary to ischemic optic neuropathy in less than 20% of patients; but this occurrence is very rare after high-dose steroid treatment. REFEENCES The Merck Manual, 17th Ed., Merck and Co., 1999, pp. 438-9. 2002 Ferri’s Clinical Advisor, Fred Ferri, Mosby 2002 Edition, p. 682.

Answer 112

Answer: C Rationale: Parkinson's disease is the leading cause of neurologic disease in people older than 65-years- old and affects approximately 1 million Americans. Typically it is characterized as an idiopathic movement disorder with akinesia, 'resting pill' rolling tremor and a shuffling gait. The primary pathogenesis is dopamine depletion in the substansia nigra of the basal ganglia. Lewy bodies (cytoplasmic inclusions) can be seen in Parkinson's disease however are localized to the cerebellum, basal ganglia, sympathetic ganglion and spinal cord and not usually the temporparietal lobe. Focal areas of demylination followed by reactive gliosis is seen in multiple sclerosis. Myesthenia gravis is an autoimmune disease causing muscular weakness from antibody mediated destruction of the acetylcholine receptor in the neuromuscular junction. Weakness is temporarily ameliorated by the administration of edrophonium, and is diagnostic for the disease. Reference: Wichmann T et al. Parkinson's disease and the basal ganglia. Lessons from the laboratory and from neurosurgery. Neuroscientist. 1:236, 1995

Answer 113

Answer: C Rationale: Cluster headaches have a much higher incidence in men than women. The pain is often retro- orbital and is described as intense and boring in character. In addition to the above symptoms, there may be miosis, ptosis, flush and cheek edema which may last for two hours. It recurs nightly for weeks to months followed by months to years of relief from symptoms. Cluster headaches can sometimes be precipitated by vasodilating agents such as alcohol, nitroglycerin, or tyramine containing foods. Cluster headaches may be prophylaxed with ergot preparations at bedtime, amitriptyline or lithium carbonate. Classic migraine headache involves painless prodromes such as visual changes (scotoma) followed by (usually unilateral) throbbing headache lasting for 6 to 8 hours and often accompanied by fatigue and photophobia. Common migraines may not be as painful or intense as classic, and do not have a prodrome. Controversy revolves around “tension headaches,” as some think they are musculoskeletal in origin although some may have a partial vascular component. Reference: Wilson, JD ed. Harrison's Principles of Internal Medicine. McGraw-Hill, Inc. 1991. p. 110- 111.

Answer 114

Answer: B Rationale: The anterior digastric is innervated by the mylohyoid branch of the mandibular nerve (V), while the posterior belly of the digastric is innervated by the facial nerve (VII). They are actually 2 embryologically distinct muscles originating from branchial arches I and II, respectively. The tensor tympani receives its motor innervation from a branch of the mandibular nerve (V). The intrinsic (genioglossus and geniohyoid) and extrinsic tongue musculature receives motor input from the hypoglossal nerve (XII). The glossopharyngeal nerve (IX) provides special sensory innervation (taste) to the posterior tongue, innervates the carotid sinus, and carries autonomic input to the parotid gland and oropharynx. The abducent (VI) nerve innervates the lateral rectus muscle, while the trochlear nerve (IV) innervates the superior oblique muscle. Reference: Goetz:Textbook of Clinical Neurology, 2nd Ed. Elsevier, 2003. Textbook of Head and Neck Anatomy, 2nd Ed. Hiatt, J and Gartner, L. Williams and Wilkins, 1987.

Answer 115

Answer: D Rationale: The outer layer of the trigeminal nerve is the epineurium; this encloses the perineurium, which is the connective tissue surrounding groups of nerve fascicles. The endoneurium is the connective tissue layer surrounding individual fascicles within the perineurium. Seddon classified nerve injuries into neurapraxia (brief conduction loss due to manipulation with rapid recovery and no axonal degeneration), axonotmesis (more severe injury with axonal damage and demyelination) and neurotmesis (complete nerve transaction). Repair of this injury should be with 2 or 3 fine non-resorbing sutures placed in the epineurial layer. Neurorrhaphy is the term for directly suturing 2 nerve ends together. Reference: Peterson's Principles of Oral and Maxillofacial Surgery, 2nd Ed. Miloro, M. (Ed.) BC Decker Inc, 2004, pp 819-837.

Answer 116

Answer: B Rationale: Wernicke's encephalopathy is a finding often associated with chronic alcoholism and is thought to be due to thiamine (Vitamin B1) deficiency. It is associated with an acute confusional state, amnesia, ataxia and opthalmoplegia. The pathogenesis is due to demyleination, neuronal loss and gliosis of the thalamus, periaqueductal gray matter, cerebellum and cranial nerve III, VI and VII. Kosakoffs syndrome is also found in chronic alcoholism is the inability to form new memories and usually seen later than Wernickes encephalopathy. It too is associated with thiamine deficiency; however A is not the answer since the episode was of acute onset. Parkinson's disease is the most common neurologic disorder in patients over 65 years old and is a progressive movement disorder. Parkinson's disease is caused by the progressive loss of dopamine-producing neurons in the substantia nigra. Diffuse axonal injury is usually seen in patients in a prolonged coma, where neurologic recovery is slow. Reference: Lieber CS. Medical disorders of alcohalism. N Eng J Med 333:1058, 1995. Victor M. Alcoholic dementia. Can J Neurol Sci 21:88, 1994

Answer 117

Answer: B Rationale: In the parasympathetic autonomic nervous system, pre- and post-ganglionic fibers synapse close to the target organ, not close to the spinal cord, as occurs in the sympathetic nervous system. Parasympathetics to the eye synapse behind the globe in the ciliary ganglion and arise from CN III. Parasympathetics to the parotid synapse in the otic ganglion and arise from CN IX. Parasympathetics to the palatal minor salivary glands and nose synapse in the pterygopalatine ganglion and arise from CN VII. The neurotransmitter at this site is acetylcholine. The optic nerve (II) has no sympathetic component. Reference: Vander, Sherman, and Luciano: “Human Physiology: The Mechanisms of Body Function”. McGraw-Hill, 1998, p.213-216. Romanes, GJ: “Cunningham's Manual of Practical Anatomy”. Oxford Medical Publications, 1986.

Answer 118

Answer: C Rationale: Maximal insulin effect is reached with plasma levels of 20-200 u/ml. This can be accomplished (ideally in an intensive care setting) by administering IV insulin with an initial bolus of 10-15 units, followed by a continuous infusion at a rate of 2-10 units/hour. The ketoacidotic patient generally presents with decreased intravascular volume, requiring volume expansion and not fluid restriction. Although serum potassium is commonly elevated by ketoacidotic shift from intracellular fluids, total body potassium is often decreased and insulin can rapidly drop serum potassium to dangerously low levels. Often, potassium is judiciously given IV with insulin to keep serum potassium at a safe level. Reference: Rose L, Kaye D:Internal Medicine for Dentistry 2nd ed., C.V. Mosby, Saint Louis, 1990, pp 1124-1125. Donoff R: Massachusetts General Hospital Manual of Oral and Maxillofacial Surgery C.V. Mosby, Saint Louis, 1987, pp 105-108. Stobo, et al: The Principles and Practice of Medicine 23rd ed., Appleton & Lange, Stamford, 1996, pp 322-328

Answer 119

Answer: D Rationale: Elevation of blood urea nitrogen in renal failure results in salivary ammonia excretion. Uremic stomatitis can occur in severe renal failure. This presents with symptoms of foul taste, halitosis, excessive salivation, as well as signs and symptoms of soft tissue stomatitis. Parotid as well as submandibular swelling may be seen in chronic renal failure with or without accompanying signs of stomatitis. Additionally, parotid swelling may be part of a malnutrition syndrome such as in alcoholism. Reference: Rose L, Kaye D: Internal Medicine for Dentistry 2nd ed., C.V. Mosby, Saint Louis, 1990, pp 587. Donoff R: Massachusetts General Hospital Manual of Oral and Maxillofacial Surgery C.V. Mosby, Saint Louis, 1987, pp 85-96. Stobo, et al: The Principles and Practice of Medicine 23rd ed., Appleton & Lange, Stamford, 1996, pp 382-388

Answer 120

Answer: D Rationale: Patients in renal failure typically exhibit specific gravity which is isothenic (1.010) or less. Also, urine osmolality is low (<300) and sodium is high (>20mmol/L). Serum creatinine will be markedly elevated quickly in the initial (oliguric) phase of acute renal failure. This case of failure is probably due to ischemic hypoperfusion from prolonged hypotension. However, deposition of myoglobin from surgical insult or hemoglobin from transfusion may also be contributing to renal tubular dysfunction. Reference: Rose L, Kaye D: Internal Medicine for Dentistry 2nd ed., C.V. Mosby, Saint Louis, 1990, pp 754. Donoff R: Massachusetts General Hospital Manual of Oral and Maxillofacial Surgery C.V. Mosby, Saint Louis, 1987, pp 144. Stobo, et al: The Principles and Practice of Medicine 23rd ed., Appleton & Lange, Stamford, 1996, pp 382-388

Answer 121

Answer: B Rationale: Hepatorenal syndrome is a relatively frequent complication in cirrhotic patients with ascites that is associated with an extremely short survival. It is a complication of advanced cirrhosis characterized by renal failure due to severe renal vasoconstriction, increases in systemic blood pressure, and increased activity of endogenous vasoactive systems. Absence of hepatomegaly, high plasma renin activity, and low serum sodium concentration are predictors of hepatorenal syndrome occurrence in these patients. The fundamental problem in hepatorenal syndrome is renal ischemia secondary to hypotension and profound renal cortical vasoconstriction, leading to renal tubular dysfunction and proteinuria. Portal hypertension and its associated splanchnic arterial vasodilatation initiate a cascade of events leading to activation of systemic and local vasoconstrictors and depletion of local renal vasodilators. Therapy with vasopressin V(1) receptor and alpha-adrenergic agonists, and plasma expanders, reverses type I and type II hepatorenal syndrome and improves survival. The first detailed description of HRS reported 9 patients with cirrhosis or acute hepatitis who developed renal failure without associated proteinuria and with very low urinary sodium excretion. On autopsy, these kidneys showed normal histology. It was later shown that kidneys from patients with HRS regain their function when transplanted into patients without cirrhosis and that HRS can be reversible following liver transplantation if done prior to irreversible renal damage. Reference: Barada K, Hepatorenal syndrome: pathogenesis and novel pharmacological targets. Curr Opin Pharmacol 2004 Apr;4(2):189-97. Cardenas A, Arroyo V; Hepatorenal syndrome. Ann Hepatol 2003 Jan-Mar;2(1):23-9. Gines A, Escorsell A, Gines P, Salo J, Jimenez W, Inglada L, Navasa M, Claria J, Rimola A, Arroyo V, et al.; Incidence, predictive factors, and prognosis of the hepatorenal syndrome in cirrhosis with ascites. Gastroenterology 1993 Jul;105(1):229-36. Hecker R, Sherlock S; Electrolyte and circulatory changes in terminal liver failure. Lancet. 1956;2:1221-1225. Iwatsuki S, Popovtzer, M Corman J, et al.; Recovery from hepatorenal syndrome after orthotopic liver transplantation. N Engl J Med. 1973;289:1155-1159. Koppe M, Coburn J, Mims M, et al; Transplantation of cadaveric kidneys from patients with hepatorenal syndrome. Evidence for the functional nature of renal failure in advanced liver disease. N Engl J Med. 1969;280:1367-1371.

Answer 122

Answer: D Rationale: All of the listed disorders can be caused by the thiamine deficiency common in malnutrition, such as found in anorexic or alcoholic individuals. Chronically malnourished individuals can manifest with numerous metabolic and electrolyte disorders, and careful nutritional diagnosis and support is vital in this patient population. Wet beriberi is a thiamine-depletion cardiovascular disorder with three major derangements: 1) peripheral vasodilatation with high-output cardiac failure 2) sodium retention and peripheral edema 3) biventricular heart failure. Wernicke's encephalopathy (cerebral beriberi) is an acutely evolving disease. Its most common manifestations include vomiting, nystagmus, ophthalmoplegia, and ataxia. Korsakoffs psycosis is primarily a disturbance of the ability to form new memories. Nutritional polyneuropathy, or dry beriberi, is a polyneuropathy involving the distal peripheral nerves. It primarily affects sensory innervation. Reference: Rose L, Kaye D: Internal Medicine for Dentistry 2nd ed., C.V. Mosby, Saint Louis, 1990, pp 744-745. Stobo, et al: The Principles and Practice of Medicine 23rd ed., Appleton & Lange, Stamford, 1996, pp 931

Answer 123

Answer: C Rationale: Infections cause gluconeogenesis and glycogenolysis. Even in Type II diabetics, exogenous insulin administration is often necessary in order to control glucose levels. Ketoacidosis leading to academia and hyperkalemia is not commonly seen even in severe hyperglycemia with Type II diabetics. However, in Type I individuals severely elevated glucose levels are indicative of insulinopenia. In severe insulin deficiency, glucose is not delivered through the cell membrane and intracellular metabolilsm uses proteins and fats, causing release of ketoacids. As ketoacidosis causes potassium shifts from inside the cells to the extracellular fluid, serum potassium values initially rise to critical levels, but total body potassium depletion occurs by renal potassium excretion. Reference: Rose L, Kaye D: Internal Medicine for Dentistry 2nd ed., C.V. Mosby, Saint Louis, 1990, pp 1124-1125. Donoff R: Massachusetts General Hospital Manual of Oral and Maxillofacial Surgery C.V. Mosby, Saint Louis, 1987, pp 105-108. Stobo, et al: The Principles and Practice of Medicine 23rd ed., Appleton & Lange, Stamford, 1996, pp 321-331

Answer 124

Answer: A Rationale: Botulinum toxin type A blocks neuromuscular conduction by binding to receptor sites on motor nerve terminals, inhibiting the release of acetylcholine. This effect is temporary, usually lasting 3 to 6 months. Reference: Coffield JA, et al. The site and mechanism of action of botulinum neurotoxin. In: Jankovic J, ed. Therapy With Botulinum Toxin. New York, NY Marcel Dekker; 1994:3-15.

Answer 125

Answer: C Rationale: Botox resistance is caused by high doses (>150 units), increased frequency of treatments, and decrease time interval between treatments, which become significant if given less than two months apart. This leads to antibody formation to the toxin. Reference: Garcia A, Fulton JE. Cosmetic denervation of the muscles of facial expression with botulinum toxin A - a dose responses study. Dermatologic Surg. 1996; 22:39-43.

Answer 126

Answer: D Rationale: Treatment of glabellar lines is easy to accomplish with minimal side effects. The most common side effect is lid ptosis, which is caused by diffusion of Botox to the superior lid muscles (levator palpebrae superioris). Lid ptosis is best done by staying 1cm above the supraorbital rim when injecting the corrugator muscles. Reference: Carruthers A, Kiene K, Carruthers J. Botulinum A exotoxin use in clinical dermatology. J AM Acad Dermatol. 1996;34:788.

Answer 127

Answer: A Rationale: The dosage for proper treatment of glabellar frown lines is 20 units given with 5 injections (4 units per injection): two injections in each corrugator muscle, and 0ne midline injection in the procerus muscle. Reference: Carruthers JDA, Carruthers A. Treatment of glabellar frown lines with C. botulinum A exotoxin. Dermatol Surg. 1996;22:39-43.

Answer 128

Answer: C Rationale: The treatment of glabellar frown lines with Botox requires injection of the procerus and corrugator muscle groups. Reference: Carruthers JDA, Carruthers A. Treatment of glabellar frown lines with C. botulinum A exotoxin. Dermatol Surg. 1996; 22:39-43

Answer 129

Answer: D Rationale: Porous implants have the potential for ingrowth of bacteria that are introduced at the time of surgery or post-operatively from tissue breakdown. This occurs when the pore size is >1micron. Macrophages require a pore size of >50 microns to enter and engulf bacteria that have infected the implant. Therefore, the ideal porous implant would have pores smaller than 1 micron to avoid bacterial inoculation or >50 microns to allow macrophages to engulf the bacteria. Reference: Cohen MS, Constantino PO, Friedman CD. Biology of implants used in head and neck surgery. Fac Plast Surg Clin North Am. 1999;9:17.

Answer 130

Answer: B Rationale: Collagen replacement therapy for lip augmentation is used to achieve fullness in the white roll area of the lip. Collagen has limited or no use in the scarred cleft lip or small lips. Perioral rhytides are best managed by other means (laser resurfacing, chemical peel, Restylane). Reference: Niamtu, J. New lip and wrinkle fillers. Oral Maxillofacial Surg Clin N Am. 2005;17:17-28.

Answer 131

Answer: D Rationale: Deep perioral rhytides can be caused by many factors: habits (such as smoking), sun damage, loss of elastic collagen in the dermal layers, and overhanging, ptotic skin. Botox and Myobloc would have minimal effect in this scenario and are not recommended for patients over age 65. Bovine collagen can exhibit a severe inflammatory response. It is also short lived, lasting as little as two months. Restylane is longer acting with fewer side effects and would be the treatment of choice. Reference: Kane, M. Botox injections for lower facial rejuvenation. Oral Maxillofacial Surg Clin N Am. 2005;17:41-49.

Answer 132

Answer: A Rationale: The use of autogenous or alloplastic materials into the lips primarily achieves an increase in lip volume and vermillion exposure. Improvement of white roll definition, perioral rhytides, or cupid's bow is inconsistent with implants. Reference: Sykes, JM, Emery BE. Upper and lower lip augmentation with dermal autografts. Oper Tech Otolaryngol Head Neck Surg. 1995;6:307 Niamtu J. Advanta facial implants. Oral Maxillofacial Surg Clin N Am. 2005;17:29

Answer 133

Answer: D Rationale: Hormone replacement therapy may contribute to melanocyte activity and pigmentary changes. It is recommended that therapy be stopped one month prior to surgery to decrease incidence. Reference: James R. Hupp, esthetic surgery of the aging face. Atlas of the Oral and Maxillofacial Surgery September 1998. Page 2

Answer 134

Answer: B Rationale: Medium depth peel will penetrate to the level of the upper reticular dermis. Superficial peel will penetrate to the level of the papillary dermis. A deep depth peel will penetrate to the level of the mid reticular dermis. Reference: James R. Hupp, esthetic surgery of the aging face. Atlas of the Oral and Maxillofacial Surgery September 1998. Page 3

Answer 135

Answer: C Rationale: Phenol is metabolized in the liver and excreted in the kidney, also has been associated with cardiac dysrhythmias. These diseases are relative contraindications to its use. Reference: James R. Hupp, esthetic surgery of the aging face. Atlas of the Oral and Maxillofacial Surgery September 1998. Page 2

Answer 136

Answer: C Rationale: Erythema up to three month is treated by observation. Erythema that persists after this period is treated with topical steroid creams. Hydroquinone is used to treat pigmentary changes. CO2 laser is of no benefit. Prolonged uses of antibiotic ointments have been implicated with persistent erythema. Reference: James R. Hupp, esthetic surgery of the aging face. Atlas of the Oral and Maxillofacial Surgery September 1998. Page 2-22

Answer 137

Answer: B Rationale: The Class II skin type patient has a white skin color that usually burns and tans minimally. The Class I skin type always burns and never tans. The Class III skin type tans moderately and burns moderately. The Class IV skin type burns minimally and tans easily. Reference: Obagi S: Skin resurfacing OMS knowledge update 2001

Answer 138

Answer: C Rationale: A history of herpetic lesions is not a contraindication to CO2 laser skin resurfacing. Recent retinoid use can predispose a patient to hypertrophic scar formation. Fitzpatrick Class V would predispose a patient to pigmentary changes. Reference: Robert A. Strauss, Steven A Guttenberg. Lasers in Oral and Maxillofacial Surgery. Oral and Maxillofacial surgery clinic may 2004 page 178-183

Answer 139

Answer: C Rationale: The dose should be increased to a herpes zoster dose. Herpetic outbreaks are very rare when the patient is taking antiherpetic medication but they do occur. Answer A is wrong since this is a prophylactic dose for acyclovir. Reference: Robert A. Strauss, Steven A Guttenberg. Lasers in Oral and Maxillofacial Surgery. Oral and Maxillofacial Surgery Clinics. May 2004 page 178-183

Answer 140

Answer: C Rationale: A chromophore is a compound or chemical capable of selective light absorption. Lasers with different wavelengths of energy will be selectively absorbed by different chromophores, therefore allowing the laser to target specific structures. The chromophore of the CO2 laser is water. For the argon laser it is hemoglobin. For the Q-switched Nd-YAG laser it is melanin. Proteins are heterogenous and do not have a specific wavelength absorption range. Reference: Guy A. Catone, Charles C. Alling. Laser Applications in Oral and Maxillofacial Surgery, WB Saunders, 1997.

Answer 141

Answer: A Rationale: The doll's hair look is seen with the cylindrical plugs. The new techniques of minigrafts and micrografts eliminate this look. Reference: James R. Hupp, esthetic surgery of the aging face. Atlas of the Oral and Maxillofacial Surgery September 1998. Page 39-51.

Answer 142

Answer: A Rationale: The yield of adipocytes does not vary with the harvesting site. It is well established that the harvesting technique, preparation of fat for transfer, and handling techniques such as prolonged exposure to air can affect the yield of viable adipocytes. Reference: Obagi S:Autologous Fat Augmentation for Addressing Facial Volume Loss: Oral Maxillofacial Surg Clin N Am 17:101-102, 2005.

Answer 143

Answer: A Rationale: The modiolus is an area of confluence of five muscles of facial expression, located lateral to the corner of the mouth. The five muscles are the levator anguli oris, zygomaticus major, risorius, platysma, and depressor anguli oris. This group of muscles is bound to the buccinator by connective tissue, and along with the cheekbone, represent the configuration of the nasolabial fold. The modiolus is not comprised of nerves and has no influence on the brow area. Reference: Vigliante CE:Anatomy and functions of the muscles of facial expression: Oral Maxillofacial Surg Clin N Am 17:14-15, 2005.

Answer 144

Answer: C Rationale: Transcutaneous blepharoplasty does not correct eyelid retraction, and occasionally will worsen the condition due to skin removal. Brow lift procedures will correct brow ptosis, but not lid ptosis. Surgery of the muscles of the upper eyelid is often performed to correct lid ptosis. Lid ptosis must be evaluated and corrected prior to a blepharoplasty procedure. A transconjunctival blepharoplasty will not correct eyelid retraction. Reference: Karesh JW: Blepharoplasty. In: James Hupp, ed. Esthetic surgery of the aging face, Atlas of the Oral and Maxillofacial Surgery Clinics of North America. September 1998 Loeb R: Esthetic surgery of the eyelids. Springer-Verlag, New York 1989

Answer 145

Answer: D Rationale: Erb's point is approximately 6 cm inferior to the lobule of the ear and along the posterior border of the sternocleidomastoid muscle, where the platysma crosses it obliquely. Remaining superficial to the fascia over the sternocleidomastoid muscle in this region ensures that injury to the greater auricular and accessory nerves is avoided. Reference: Waite PD, Cuzalina LA: Rhytidectomy (Face Lift). In Fonseca R, Baker S, Wolford LM (eds). Oral and Maxillofacial Surgery, Vol 6, WB Saunders, Philadelphia, 2000

Answer 146

Answer: A Rationale: The marginal mandibular branch of the facial nerve lies deep to the platysma in this area until about 2 cm lateral to the commissural of the mouth, at which stage, it penetrates the undersurface of the facial mimetic muscles, and is found more superficially. Reference: Waite PD, Cuzalina LA: Rhytidectomy (Face Lift). In Fonseca R, Baker S, Wolford LM (eds). Oral and Maxillofacial Surgery, Vol 6, WB Saunders, Philadelphia, 2000

Answer 147

Answer: C Rationale: Some surgeons consider smoking as an absolute contraindication; however, most recommend that smoking be stopped at least 1-2 weeks before surgery and for 2 weeks postoperatively. The overall complication rate for patients who continue to smoke is more than twice those who stop smoking. Reference: Waite PD, Cuzalina LA: Rhytidectomy (Face Lift). In Fonseca R, Baker S, Wolford LM (eds). Oral and Maxillofacial Surgery, Vol 6, WB Saunders, Philadelphia, 2000

Answer 148

Answer: B Rationale: MacGregor's patch is also known as the “bloody gulch.” It is named after the strong zygomaticodermal fibrous attachments that often present as skin dimpling or retraction. It is also pertinent because a plexus of vessels supplied by the facial artery and transverse facial artery becomes superficial in this area. Also, the buccal nerve lies just deep to this danger zone, and the zygomatic branch of the facial nerve becomes more superficial in this area. Reference: Waite PD, Cuzalina LA: Rhytidectomy (Face Lift). In Fonseca R, Baker S, Wolford LM (eds). Oral and Maxillofacial Surgery, Vol 6, WB Saunders Philadelphia, 2000.

Answer 149

Answer: C Rationale: Injury to the facial nerve causing paralysis is rare, and reported only to occur in 0.53 to 2.6 % of patients. 85 % of motor nerve injuries resolve spontaneously, and results of surgical repair are unpredictable and not very encouraging. Injury to the greater auricular nerve is most common, and occurs in up to 7 % of patients. Temporary neuropraxia usually resolves in 2-4 months, and causes numbness/paresthesia around the inferior portion of the ear and surrounding skin. Transection of the nerve is best treated with immediate microanastomosis. Reference: Waite PD, Cuzalina LA: Rhytidectomy (Face Lift). In Fonseca R, Baker S,Wolford LM (eds). Oral and Maxillofacial Surgery, Vol 6, WB Saunders, Philadelphia, 2000

Answer 150

Answer: B Rationale: In the “normal “ ear, the posterior wall of the conchal bowl is set at about 90 degrees to the mastoid. A second 90-degree angle is formed at the antihelical fold, and is called the scapha- conchal angle. These two angles, in combination with the curvature of the helix, set the auricle adjacent to the scalp at approximately 25-35 degrees. Reference: Tanzer RC: Congenital deformities. In, Converse J (ed): Reconstructive Plastic Surgery, Vol 4, 2nd edition, Philadelphia, WB Saunders, 1977.

Answer 151

Answer: D Rationale: The sensory nerve supply is primarily from the anterior and posterior branches of the greater auricular nerve. This nerve travels 8 cm posterior to the postauricular crease. The auriculotemporal and lesser occipital nerves supply the conchal cavity and external auditory meatus, and auricular branches of the Vagus may supply the posterior wall of the external auditory meatus. Reference: Owsley TG, Tejera TJ:Otoplastic surgery for the protruding ear. In, Fonseca R, Baker S, Wolford LM (eds). Oral and Maxillofacial Surgery, Vol 6, WB Saunders, Philadelphia, 2000

Answer 152

Answer: C Rationale: The Mustarde technique involves cartilage weakening and placement of a series of horizontal mattress sutures to create an antihelical fold. The Davis technique corrects conchal hypertrophy by stepwise cartilage excision. The Converse-Wood Smith technique involves several full-thickness cuts through the cartilage and suturing to form an antihelical fold; these sharp ridges can often be felt/seen through the thin anterior skin. The Furnas technique has a high incidence of relapse and is a postauricular approach, where the muscle is removed and sutures placed from the mastoid fascia to the ear cartilage. Reference: Owsley TG, Tejera TJ:Otoplastic surgery for the protruding ear. In, Fonseca R, Baker S, Wolford LM (eds). Oral and Maxillofacial Surgery, Vol 6, WB Saunders, Philadelphia, 2000

Answer 153

Answer: D Rationale: Perichondritis occurs in the early postoperative period, and is usually related to an undetected or inadequately treated hematoma. Symptoms include pain, erythema, fever, and discharge. Treatment included high doses of antibiotics following wound cultures, and establishing adequate drainage. Massive cartilage destruction and severe ear deformities can result, despite aggressive treatment. Reference: Owsley TG, Tejera TJ: Otoplastic surgery for the protruding ear. In, Fonseca R, Baker S, Wolford LM (eds). Oral and Maxillofacial Surgery, Vol 6, WB Saunders, Philadelphia, 2000.

Answer 154

Answer: B Reference: Owsley TG, Tejera TJ: Otoplastic surgery for the protruding ear. In, Fonseca R, Baker S, Wolford LM (eds). Oral and Maxillofacial Surgery, Vol 6, WB Saunders, Philadelphia, 2000

Answer 155

Answer: B Rationale: The CO2 and Erbium:Yag laser have different tissue effects. The thermal effects of the CO2 laser leaves a relatively wide zone of coagulation necrosis, which results in highly effective hemostasis, and produces immediate visible collagen shrinkage of up to 25 percent during irradiation. In contrast, the erbium laser has less extensive coagulation necrosis, which permits for more bleeding and only 1-2 percent of collagen shrinkage. Reference: Tina, A. Cutaneous Resurfacing with CO2 and Erbium: Yag lasers: Preoperative, Intraoperative, and Postoperative Considerations. Plastic and Reconstructive Surgery. 103(2), 619-632. 1999

Answer 156

Answer: C Rationale: Phenol is rapidly absorbed through the skin and metabolized through the liver, and excreted by the kidney. It can lead to renal failure and hepatotoxicity, and can directly irritate the myocardium, inducing dysrythmias. Reference: Demas, P, Braun, T. Chemical Skin Resurfacing. Atlas of Oral and Maxillofacial Surgery. 6(2) 1-22. 1998.

Answer 157

Answer: D Rationale: Crow's feet are addressed by injecting the orbicularis oculi muscle in a semi-lunar pattern. Care is taken to maintain a 1cm distance from the lateral orbital rim to avoid diploplia from inadvertent injection into the lateral rectus muscle. Reference: Obagi S. Correction of surface deformities; Botox, soft-tissue fillers, lasers and intense pulsed light, and radiofrequency. Atlas of Oral and Maxillofacial Surgery Clinics of North America. 12. 271-297. 2004

Answer 158

Answer: C Rationale: The most ideal position of the cheek eminence is located 10mm lateral and 15-20mm inferior to the lateral canthus. This mark aids in the proper superior-inferior and lateral positioning of the cheek implant. Reference: Epker B. Maxillofacial contour esthetic deformities. Atlas of Oral and Maxillofacial Surgery clinics of North America. 12. 75-89.2004

Answer 159

Answer: B Rationale: The upper eyelid contains 2 fat pads: the medial and central fat pads which may be removed during upper eyelid blepharoplasty. The lower eyelid contains 3 fat pads: the medial, central, and lateral fat pads. In the upper eyelid, the lateral compartment is occupied by the lacrimal gland and should not be disturbed during upper eyelid blepharoplasty. Reference: Jarecki HL, Lucarelli MJ, Lemke BN: Blepharoplasty. Peterson's Principls of Oral and Maxillofacial Surgery 2nd Edition. 2004: pp 1317-1344

Answer 160

Answer: C Rationale: Injury to the upper eyelid levator aponeuroris may result in ptosis. Dry eye may result from resection of the lacrimal gland. Diplopia is a complication of lower lid blepharoplasty. And Lagophthalmos results from excessive skin/muscle excision. Reference: Jarecki HL, Lucarelli MJ, Lemke BN: Blepharoplasty. Peterson's Principls of Oral and Maxillofacial Surgery 2nd Edition. 2004: pp 1317-1344

Answer 161

Answer: A Rationale: The supratarsal fold is produced by the insertion of the levator aponeurosis into the skin of the upper eyelid. Reference: Delgado JA, Jacobs JL, Baylis HI, Goldberg RA: Blepharoplasty and Periorbital Surgery. Facial Plastic Surgery Clinics of North AmericA.1998: pp 41-58

Answer 162

Answer: B Rationale: Orbital hematoma may develop after orbital fat excision. This may result in increased intraorbital pressure with compression of the central retinal artery causing blindness. Reference: Hatt M: Ophthalmic Plastic and Reconstructive Surgery. New York. Thieme Inc. pp 153- 159.

Answer 163

Answer: B Rationale: Transconjunctival blepharoplasty has been shown to have a significantly reduced risk of lower lid retraction. Reference: Jacono AA, Moskowitz B:Facial Plastic Surgery. Vol 17(1). 2001:pp 21-27.

Answer 164

Answer: D Rationale: Mandibular angle augmentation may be performed by an intraoral approach by placing the implant in a subperiosteal position, deep to the masseter muscle. Reference: Epker BN. Alloplastic Esthetic Facial Augmentation. Peterson's Principals of Oral and Maxillofacial Surgery 2nd Edition. 2004:1435 – 1447.

Answer 165

Answer: C Rationale: The osteotomy should be designed to avoid the inferior course of the mental foramen and must be placed 5 mm below the mental foramen. Reference: Hwang KL, Song YB, Chung IH. Vulnerability of the Inferior Alveolar Nerve and Mental Nerve during Genioplasty:an anatomic study. J Craniofac Surg 200516(1):10-4, 2005.

Answer 166

Answer: A Rationale: Povidone-iodine solution is not harmful to the eye. Chlorhexidine has the potential to lyse corneal epithelium. Hydryogen peroxide is a distractor. Castille solution has no therapeutic benefit as a presurgical antimicrobial. Solutions containing alcohol can be harmful to the eye. Reference: Fonseca, R.J., et al: Oral and Maxillofacial Surgery, Volume 6: Cleft/Craniofacial/Cosmetic Surgery. pp 355

Answer 167

Answer: B Rationale: The snap and distraction tests are used prior to laser blepharoplasty resurfacing to identify patients who may be at risk for lower lid ectropion. Reference: Guttenberg SA, Emery RW. Laser Cosmetic Skin Resurfacing: Superpulse Perspective. Oral and Maxillofacial Surgery Clinics of North America. May 2004. Vol 16(2): 197-213.

Answer 168

Answer: A Rationale: The intercartilagenous incision is used to access the nasal dorsum when little or no tip alteration is necessary in the closed rhinoplasty approach. The intracartilagenous approach will facilitate a cephalic trimming of the lower lateral cartilage. A marginal incision combined with a transcolumellar incision is used for the open rhinoplasty. Complete tip exposure, particularly to view the lower lateral cartilages in their correct anatomic position is best done with the open approach. Reference: Rhinoplasty:Calhoun KH, in Atlas of Head and Neck Surgery-Otolaryngology:Baily BJ, Calhoun KH, Coffey AR, Neely JG, Lippencott-Raven, Philadelphia, pp. 450-451, 1996.

Answer 169

Answer: B Rationale: Columellar show is the amount of columella which is seen below the alar rim. This is normally in the range of 2 to 4mm. Excessive or insufficient columellar show should be addressed in esthetic rhinoplasty. Reference: Nasal-Facial Analysis, McGraw-Wall BL, in Atlas of Head and Neck Surgery- Otolaryngology: Baily BJ, Calhoun KH, Coffey AR, Neely JG, Lippencott-Raven, Philadelphia, pp. 442-443, 1996.

Answer 170

Answer: B Rationale: The internal nasal valve is formed by the junction of the upper lateral cartilage and the nasal septum. Spreader grafts are placed to increase the size of this junction, hence improving nasal airway breathing, and in some cases, nasal esthetics. Reference: Rohrich R, et al.: Use of Spreader Grafts in External Approach to Rhinoplasty. In, Clinics in Plastic Surgery, 255-262, 1996.

Answer 171

Answer: C Rationale: The transfixion and hemitransfixion incision provide access to the caudal septum in endonasal rhinoplasty. The complete transfixion incision separates the medial crura from the septum. The hemitransfixion incision is only made on one side, and usually stops short of the anterior nasal spine, preserving tip support. The nasal dorsum is not approached with the transfixion incision. The transcolumellar incision is used in an open approach and is not normally combined with either the transfixion or hemi-transfixion incision. Reference: Sublabial and Septal Incisions: Renner G, in Atlas of Head and Neck Surgery- Otolaryngology: Baily BJ, Calhoun KH, Coffey AR, Neely JG, Lippencott-Raven, Philadelphia, pp. 853-853, 1996.

Answer 172

Answer: C Rationale: The nasofrontal angle is the angle between a line connecting the nasal bridge and nasion and a line connecting nasion and glabellA. Nasion is ideally located at the upper eyelid margin and 4-6mm behind the glabellA. Reference: Nasal-Facial Analysis: McGraw-Wall BL, in Atlas of Head and Neck Surgery- Otolaryngology: Baily BJ, Calhoun KH, Coffey AR, Neely JG, Lippencott-Raven, Philadelphia, pp. 442-443, 1996.