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NBDE Part II study materials
NBDE Part II study resources

NBDE Part II practice questions

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Question 1Endodontics

When establishing working length for a tooth with a normal apical anatomy, the file tip should ideally terminate at which location?

  1. At the level where a size 40 file first binds in the canal
  2. At the radiographic apex
  3. 2.0 mm beyond the radiographic apex
  4. 0.5 to 1.0 mm short of the radiographic apex Correct answer.

Explanation

The apical constriction, the narrowest part of the canal, typically lies 0.5 to 1.0 mm coronal to the radiographic apex. Instrumenting and obturating to this landmark preserves the apical tissues and limits extrusion of debris and filling material.

Question 2Endodontics

Which factor is considered the principal cause of post-treatment apical periodontitis?

  1. Overextension of the obturation material
  2. Long-standing coronal microleakage
  3. Occlusal trauma from bruxism
  4. Intraradicular microbial infection Correct answer.

Explanation

Microorganisms that survive in the apical portion of the canal system, including biofilms in fins, isthmuses, and dentinal tubules, are the main cause of persistent post-treatment disease. Coronal leakage matters chiefly because it permits new bacterial entry.

Question 3Endodontics

Which irrigating solution removes the inorganic portion of the smear layer by chelating calcium ions?

  1. 3% hydrogen peroxide
  2. Sodium hypochlorite
  3. 17% EDTA Correct answer.
  4. Chlorhexidine gluconate

Explanation

EDTA is a chelating agent that binds divalent cations and dissolves the inorganic component of the smear layer. Sodium hypochlorite, by contrast, dissolves organic tissue but leaves the smear layer largely intact.

Question 4Endodontics

A size 25 ISO hand file is identified by which color-coded handle?

  1. Blue
  2. White
  3. Yellow
  4. Red Correct answer.

Explanation

ISO hand instruments follow a standard color sequence: size 15 is white, 20 yellow, 25 red, 30 blue, 35 green, and 40 black. Only the size number, not the color, defines the tip diameter in hundredths of a millimeter.

Question 5Endodontics

Which description matches the most commonly reported root canal anatomy of a maxillary first molar?

  1. Two roots and three canals
  2. Three roots and four canals Correct answer.
  3. Three roots and three canals
  4. Two roots and four canals

Explanation

The maxillary first molar usually has three roots (mesiobuccal, distobuccal, and palatal) and four canals, because a second mesiobuccal canal is found in the majority of these teeth. Locating the MB2 is a routine part of treatment.

Question 6Endodontics

A patient reports sharp pain to cold that lingers for about 30 seconds after the stimulus is removed. The tooth is not tender to percussion, and the periapical radiograph appears normal. Which diagnosis is most appropriate?

  1. Symptomatic irreversible pulpitis Correct answer.
  2. Pulpal necrosis
  3. Asymptomatic apical periodontitis
  4. Reversible pulpitis

Explanation

Pain that persists well beyond removal of a cold stimulus indicates that the pulp can no longer recover, which defines symptomatic irreversible pulpitis. Normal percussion and periapical tissues show the inflammation has not yet spread apically.

Question 7Endodontics

A mandibular first molar has a draining sinus tract on the buccal mucosa. The pulp does not respond to cold testing, and a periapical radiolucency is present. Which is the most appropriate definitive treatment?

  1. Systemic antibiotics without pulp treatment
  2. Extraction and immediate implant placement
  3. Incision and drainage alone
  4. Nonsurgical root canal treatment Correct answer.

Explanation

A sinus tract with a nonvital pulp represents a chronic apical abscess of endodontic origin, and removing the intraradicular infection by nonsurgical root canal treatment resolves the vast majority of cases. The tract closes once the source of infection is eliminated.

Question 8Endodontics

A 9-year-old traumatically exposes the pulp of an immature maxillary central incisor; the pulp is necrotic and the apex is widely open. Which treatment creates a hard-tissue barrier so the canal can later be obturated?

  1. Placement of a fiber post immediately after cleaning
  2. Conventional gutta-percha obturation to the radiographic apex
  3. Apexification with a calcium silicate apical plug Correct answer.
  4. Extraction with delayed implant placement

Explanation

When the pulp is necrotic and the apex is open, apexification induces a calcified barrier against which the canal can eventually be filled. Placing a calcium silicate cement plug in the apical portion accomplishes this in a single visit and strengthens the fragile root end.

Question 9Endodontics

A mandibular first premolar has two separate canals that run independently from the pulp chamber to two distinct apical foramina. Which Vertucci classification applies?

  1. Type III
  2. Type I
  3. Type II
  4. Type IV Correct answer.

Explanation

Vertucci type IV describes two separate canals that run from the chamber to the apex and end in two foramina. Type I is a single canal, type II describes two canals that exit as one, and type III describes one canal that splits and rejoins.

Question 10Endodontics

A canal has just been irrigated with sodium hypochlorite. Which irrigant should not be introduced immediately afterward unless an intervening rinse is used?

  1. 17% EDTA followed by saline
  2. Sterile saline
  3. Chlorhexidine gluconate Correct answer.
  4. 3% hydrogen peroxide

Explanation

Sodium hypochlorite and chlorhexidine react to form an orange-brown precipitate that can occlude the canal and discolor the tooth. Rinsing with saline or EDTA between the two agents prevents the interaction.

Question 11Endodontics

Which property of chlorhexidine distinguishes it from sodium hypochlorite when used as an endodontic irrigant?

  1. It liberates chlorine and dissolves organic debris
  2. It dissolves necrotic tissue more effectively
  3. It chelates calcium and removes the smear layer
  4. It binds to dentin, giving substantivity Correct answer.

Explanation

Chlorhexidine adsorbs to dentin and is released gradually, producing antimicrobial substantivity that persists for hours after irrigation. It is not a tissue solvent and has no chelating action.

Question 12Endodontics

A patient returns 24 hours after the first visit of root canal therapy with markedly increased pain and swelling. Which factor is most frequently associated with this flare-up?

  1. Extrusion of sealer beyond the apical foramen
  2. Placement of a rubber dam during instrumentation
  3. Apical extrusion of infected dentin debris Correct answer.
  4. Occlusal reduction at the first appointment

Explanation

Flare-ups usually result from forcing infected debris past the apical constriction during instrumentation, which triggers an acute inflammatory response in the periapical tissues. Careful working length control and minimal apical enlargement reduce this risk.

Question 13Endodontics

A C-shaped canal system is encountered most often in which tooth?

  1. Mandibular central incisor
  2. Maxillary first premolar
  3. Mandibular second molar Correct answer.
  4. Maxillary lateral incisor

Explanation

C-shaped canals result from failure of the Hertwig epithelial root sheath to fuse on the lingual or buccal side, and they occur most often in mandibular second molars. The ribbon-shaped space requires careful shaping and thermomechanical filling.

Question 14Endodontics

During irrigation of a maxillary premolar, the patient suddenly reports severe burning pain, and marked swelling and ecchymosis develop in the buccal vestibule. Which is the most appropriate immediate management?

  1. Complete the obturation at once to seal the canal
  2. Continue irrigation at a lower concentration
  3. Apply warm compresses and prescribe antibiotics
  4. Stop irrigation, rinse with saline, give analgesics Correct answer.

Explanation

These findings indicate extrusion of sodium hypochlorite into the periapical tissues. Management is to stop irrigation immediately, rinse the canal with saline, control pain with analgesics, apply cold compresses during the first 24 hours, and allow the tissues to resolve before obturation.

Question 15Endodontics

Which instrumentation technique uses a clockwise rotation of about 60 degrees to engage dentin, followed by a larger counterclockwise rotation of about 120 degrees to cut and remove debris?

  1. Balanced force Correct answer.
  2. Step-back preparation
  3. Crown-down preparation
  4. Watch-winding

Explanation

Balanced force instrumentation combines a controlled clockwise engagement with a larger counterclockwise cutting rotation, which transports debris coronally while keeping the file centered. This makes it effective in curved canals where torsional stress is a concern.

Question 16Endodontics

Which combination of findings most strongly suggests a vertical root fracture in a previously treated premolar?

  1. Diffuse widening of the apical periodontal ligament space
  2. A sinus tract with a large, round periapical radiolucency
  3. A deep, narrow pocket with a J-shaped radiolucency Correct answer.
  4. Generalized horizontal bone loss with increased mobility

Explanation

A deep, narrow, isolated pocket that does not respond to periodontal therapy, together with a J-shaped or halo radiolucency along the root, is characteristic of a vertical root fracture. The fracture provides a direct pathway for bacterial colonization of the periodontal space.

Question 17Operative Dentistry

For a standard light-cured hybrid composite, the maximum recommended increment thickness that allows adequate depth of cure is approximately:

  1. 1.0 mm
  2. 2.0 mm Correct answer.
  3. 4.0 mm
  4. 6.0 mm

Explanation

Light transmission through filled resin falls off sharply with thickness, so increments must be thin enough for the photoinitiator to convert monomer throughout the mass. Two millimeters is the accepted maximum for most conventional shades when a functioning curing light is used.

Question 18Operative Dentistry

Which restorative material bonds chemically to tooth structure and releases fluoride over time?

  1. Conventional glass ionomer cement Correct answer.
  2. Admixed amalgam
  3. Microfilled composite resin
  4. Zinc phosphate cement

Explanation

Glass ionomer cements set by an acid-base reaction between fluoroaluminosilicate glass and polyalkenoic acid, and the polymer chains chelate calcium in enamel and dentin to give a true chemical bond. Fluoride held in the glass is released over the life of the restoration.

Question 19Operative Dentistry

The main purpose of the rubber dam during operative procedures is to:

  1. Isolate the operating field and control moisture Correct answer.
  2. Shorten the setting time of restorative materials
  3. Eliminate the need for local anesthesia
  4. Increase the depth of cure of composites

Explanation

The rubber dam isolates the field from saliva and sulcular fluid, protects the airway from dropped instruments and debris, and keeps the field dry so adhesive steps are not contaminated. Adequate isolation is a prerequisite for predictable bonding.

Question 20Operative Dentistry

Resistance form in cavity preparation refers to features that:

  1. Retain the restoration against displacement along the path of insertion
  2. Protect the pulp from thermal change
  3. Provide a rough surface for mechanical interlocking
  4. Prevent fracture of the tooth and restoration under occlusal loading Correct answer.

Explanation

Resistance form is the geometry of the preparation, including adequate depth, rounded internal line angles, flat floors, and sufficient remaining tooth structure, that resists fracture of the tooth and restoration under load. Retention form is the separate concept that resists displacement along the path of insertion.

Question 21Operative Dentistry

Delayed expansion of an amalgam restoration is caused by:

  1. Rapid cooling of the restoration after carving
  2. A low mercury-to-alloy ratio
  3. Moisture contamination during condensation Correct answer.
  4. Excessive trituration of the alloy

Explanation

Water or saliva incorporated while amalgam is being condensed reacts with the alloy to liberate hydrogen gas, and the resulting pressure expands the restoration weeks to months later. The expansion may produce a proud restoration, marginal breakdown, and pain.

Question 22Operative Dentistry

Applying 35% phosphoric acid gel to dentin for approximately 15 seconds primarily:

  1. Obliterates the dentinal tubules by precipitating calcium salts
  2. Increases the mineral content of intertubular dentin
  3. Removes the smear layer and exposes a collagen network for resin infiltration Correct answer.
  4. Eliminates bacteria and therefore removes the need for a primer

Explanation

Acid dissolves the smear layer and superficial apatite, leaving a demineralized zone of exposed collagen into which hydrophilic primer and adhesive diffuse to form the hybrid layer. The primer is essential because resin cannot spontaneously infiltrate wet, collapsed collagen.

Question 23Operative Dentistry

When placing a Class II restoration, the wedge is used mainly to:

  1. Isolate the tooth from oral fluids
  2. Separate the teeth slightly and adapt the matrix band to the gingival margin Correct answer.
  3. Increase the depth of the proximal box
  4. Prevent the matrix band from extending below the gingival margin

Explanation

Wedging produces slight tooth separation so the band hugs the gingival seat and compensates for band thickness. This helps establish a correctly contoured contact and reduces the risk of an overhang or an open gingival margin.

Question 24Operative Dentistry

Eugenol-containing temporary materials should be avoided beneath a composite restoration because:

  1. They permanently discolor enamel
  2. Residual eugenol can interfere with resin polymerization Correct answer.
  3. They cause the composite to expand on setting
  4. They prevent enamel from being etched

Explanation

Eugenol is a phenolic compound that can act as a radical scavenger and plasticizer, so residual eugenol in dentin may reduce the degree of conversion and the bond strength of resin composite. A non-eugenol temporary material is preferred when composite is planned.

Question 25Operative Dentistry

A calcium hydroxide liner placed over a deep dentin area primarily:

  1. Provides rigid support for amalgam condensation
  2. Promotes formation of reparative dentin Correct answer.
  3. Seals dentin with an impermeable barrier
  4. Bonds chemically to composite resin

Explanation

Calcium hydroxide is strongly alkaline and induces a narrow zone of necrosis followed by tertiary dentin formation by the pulp. Because it is soluble and weak, it is used as a thin liner beneath a stronger base rather than as a structural base.

Question 26Operative Dentistry

A bevel on the enamel cavosurface margin of a Class III composite restoration is placed mainly to:

  1. Reduce the polymerization shrinkage of the composite
  2. Improve the resistance form of the preparation
  3. Increase the etched enamel surface area and hide the margin Correct answer.
  4. Provide space for a thicker layer of opaque resin

Explanation

Beveling exposes enamel rods end-on, which etch into a larger and more retentive surface, and it allows a gradual transition from composite to tooth. The result is a better marginal seal and a less visible margin.

Question 27Operative Dentistry

The function of a silane coupling agent when cementing a silica-based ceramic restoration is to:

  1. Neutralize residual hydrofluoric acid
  2. Increase the radiopacity of the restoration
  3. Chemically link the ceramic surface to the resin cement Correct answer.
  4. Etch the ceramic surface

Explanation

Silane carries silanol groups that condense with hydroxyl groups on the etched silica surface and methacrylate groups that copolymerize with the resin cement. This creates a chemical bridge across the ceramic-cement interface.

Question 28Operative Dentistry

If a curing light delivers less irradiance than expected, the best way to ensure adequate polymerization is to:

  1. Cure only through the matrix band
  2. Hold the tip farther from the restoration
  3. Increase the exposure time proportionally Correct answer.
  4. Use a thicker single increment

Explanation

Depth of cure depends on total energy density, the product of irradiance and exposure time. When irradiance falls, exposure time must be increased to deliver the same energy to the material.

Question 29Operative Dentistry

Two weeks after placement of a Class II composite, a patient reports sharp cold sensitivity that lasts a few seconds and is improving. The most likely cause is:

  1. Fluid movement through unsealed dentinal tubules at the restoration interface Correct answer.
  2. Complete necrosis of the pulp
  3. Irreversible pulpitis requiring endodontic treatment
  4. Fracture of the cusps adjacent to the restoration

Explanation

Brief, improving cold response indicates dentin hypersensitivity from open tubules or a marginal gap that permits fluid shift. Such sensitivity usually resolves as the adhesive seals and the smear layer reforms, whereas lingering or spontaneous pain would suggest pulpal pathosis.

Question 30Operative Dentistry

During caries excavation in a permanent tooth, which approach is correct?

  1. Caries removal is limited to enamel because dentin remineralizes completely on its own
  2. All acid-softened dentin must be removed until only hard, sound dentin remains
  3. Excavation must be performed only with a round steel bur in a slow-speed handpiece
  4. Soft, infected dentin is removed while leathery, affected dentin may be retained Correct answer.

Explanation

Infected dentin is heavily contaminated and irreversibly denatured, so it must be removed, whereas affected dentin is demineralized but retains a collagen scaffold that can remineralize. Preserving affected dentin in deep lesions reduces the risk of unnecessary pulp exposure.

Question 31Operative Dentistry

Which of the following preparation situations produces the highest configuration factor (C-factor) for a bonded composite?

  1. A Class I preparation with a small occlusal access and a deep pulpal floor Correct answer.
  2. A Class IV restoration involving the incisal angle
  3. A pit-and-fissure sealant on an unprepared occlusal surface
  4. A Class II MOD preparation with wide proximal boxes

Explanation

C-factor is the ratio of bonded surface area to unbonded (free) surface area. A small occlusal access with a deep preparation leaves nearly every wall bonded and only a tiny free surface, so shrinkage cannot be relieved by flow and interfacial stress rises.

Question 32Operative Dentistry

Hydrofluoric acid etching followed by silane application is an appropriate surface treatment for which restoration?

  1. A densely sintered alumina core
  2. A leucite-reinforced glass ceramic inlay Correct answer.
  3. A zirconia-based crown
  4. A metal-ceramic crown with exposed metal margins

Explanation

Hydrofluoric acid selectively dissolves the glass phase of silica-based ceramics, creating a microretentive surface that silane then chemically bonds to resin cement. Materials with little or no glass phase require a different protocol, typically alumina particle abrasion plus a phosphate monomer.

Question 33Operative Dentistry

A Class II composite restoration is found to have an open proximal contact at the postoperative check. Which factor most likely contributed?

  1. Failure to place a bevel on the occlusal margin
  2. Excessive etching time on the proximal enamel
  3. Inadequate wedging and poor matrix band adaptation Correct answer.
  4. Over-curing of the composite with a high-output light

Explanation

The proximal contour is created by the matrix band; without a well-adapted band and proper wedging to offset band thickness and slightly separate the teeth, the contact will be flat or open. Polymerization shrinkage toward the bulk of the tooth further pulls the material away from the adjacent tooth.

Question 34Operative Dentistry

Compared with enamel, bonding a restoration to root-surface dentin and cementum is less predictable mainly because:

  1. These substrates contain more water and organic matrix and less mineral Correct answer.
  2. Etching cementum produces the same microporous pattern as etched enamel
  3. Cementum contains a higher proportion of hydroxyapatite than enamel
  4. Resin monomers are incapable of penetrating dentin of any type

Explanation

Enamel is roughly 96% mineral by weight and etches into a stable, microporous pattern, whereas root dentin and cementum are far wetter and richer in collagen. The resulting bonded interface is more vulnerable to hydrolysis, nanoleakage, and degradation over time.

Question 35Oral and Maxillofacial Surgery and Pain Control

What is the maximum recommended dose of lidocaine administered with 1:100,000 epinephrine to a healthy 70-kg adult?

  1. 300 mg
  2. 1,000 mg
  3. 200 mg
  4. 500 mg Correct answer.

Explanation

Lidocaine with a vasoconstrictor is limited to 7 mg/kg, with an absolute ceiling of 500 mg in a healthy adult. For a 70-kg patient the weight-based figure is 490 mg, so the dose is capped at 500 mg.

Question 36Oral and Maxillofacial Surgery and Pain Control

A patient has bilateral swelling of the submandibular and sublingual spaces, tongue elevation, and a firm, board-like floor of the mouth. What is the most appropriate immediate management priority?

  1. Obtain a panoramic radiograph before any other step is taken
  2. Prescribe oral clindamycin and arrange follow-up in 48 hours
  3. Secure the airway and arrange urgent surgical drainage Correct answer.
  4. Perform an incisional biopsy of the indurated tissue

Explanation

This presentation is Ludwig angina, a rapidly spreading bilateral cellulitis of the submandibular, sublingual, and submental spaces that can obstruct the airway. Airway protection takes precedence, followed by intravenous antibiotics and wide surgical drainage of all involved spaces.

Question 37Oral and Maxillofacial Surgery and Pain Control

Which medication is considered first-line pharmacologic therapy for classic trigeminal neuralgia?

  1. Carbamazepine Correct answer.
  2. Amitriptyline
  3. Ibuprofen
  4. Gabapentin

Explanation

Carbamazepine is the best-established first-line agent for trigeminal neuralgia and typically produces the greatest reduction in paroxysmal lancinating pain. Other anticonvulsants and tricyclics are generally reserved for intolerance or failure of carbamazepine.

Question 38Oral and Maxillofacial Surgery and Pain Control

Which structure is the most commonly fractured bone of the facial skeleton?

  1. Mandibular angle
  2. Orbital floor
  3. Zygomatic arch
  4. Nasal bone Correct answer.

Explanation

The nasal bone is the most frequently fractured facial bone because of its prominent, unprotected midline position. Mandibular and zygomatic fractures are common but occur less often overall.

Question 39Oral and Maxillofacial Surgery and Pain Control

A patient becomes pale and diaphoretic and briefly loses consciousness while watching a local anesthetic injection. Which action is most appropriate?

  1. Seat the patient upright and offer a glass of water
  2. Place the patient supine with the legs elevated Correct answer.
  3. Apply nasal oxygen with the patient sitting upright
  4. Administer 0.3 mg of epinephrine intramuscularly

Explanation

This is vasovagal syncope, caused by a sudden drop in venous return and cerebral perfusion. Placing the patient supine with the legs elevated restores central blood volume and usually produces rapid recovery.

Question 40Oral and Maxillofacial Surgery and Pain Control

Four days after removal of a mandibular third molar, a patient reports severe throbbing pain and an empty socket with exposed bone. What is the most appropriate management?

  1. Irrigate the socket and place a medicated dressing Correct answer.
  2. Prescribe systemic antibiotics as the sole treatment
  3. Curette the socket vigorously until fresh bleeding is induced
  4. Close the socket primarily with a rotated flap

Explanation

This is alveolar osteitis (dry socket), caused by fibrinolysis and loss of the protective clot. Treatment is palliative: gentle irrigation to remove debris followed by a medicated dressing such as eugenol or iodoform gauze.

Question 41Oral and Maxillofacial Surgery and Pain Control

Which statement best describes moderate (conscious) sedation?

  1. Loss of protective reflexes with inability to maintain a patent airway independently
  2. Complete lack of response to painful stimuli requiring airway support
  3. General anesthesia with muscle relaxation and controlled ventilation
  4. Depression of consciousness with purposeful response to verbal commands Correct answer.

Explanation

Moderate sedation is a drug-induced depression of consciousness in which the patient still responds purposefully to verbal or light tactile stimulation and maintains the airway without assistance. Protective reflexes remain intact and spontaneous ventilation is adequate.

Question 42Oral and Maxillofacial Surgery and Pain Control

Which anatomic structure is the target for a conventional inferior alveolar nerve block?

  1. The pterygomaxillary fissure posterior to the maxilla
  2. The mental foramen on the lateral aspect of the mandible
  3. The greater palatine foramen on the palatal process
  4. The lingula on the medial surface of the ramus Correct answer.

Explanation

The inferior alveolar nerve enters the mandibular foramen, which lies just behind and lateral to the lingula on the medial surface of the ramus. A successful block deposits solution near this bony landmark.

Question 43Oral and Maxillofacial Surgery and Pain Control

Which condition warrants antibiotic prophylaxis before an invasive dental procedure according to current American Heart Association guidance?

  1. Implanted cardiac pacemaker
  2. Mitral valve prolapse without regurgitation
  3. Prosthetic heart valve or previous infective endocarditis Correct answer.
  4. Coronary artery bypass grafting performed 5 years ago

Explanation

Prophylaxis is recommended for the highest-risk cardiac conditions: prosthetic valves, prior infective endocarditis, certain unrepaired or partially repaired congenital heart disease, and transplant valvulopathy. Most other cardiac diagnoses no longer require prophylaxis.

Question 44Oral and Maxillofacial Surgery and Pain Control

Epidemiologic surveillance data most strongly associate which local anesthetic with an elevated risk of persistent paresthesia after inferior alveolar nerve block?

  1. Mepivacaine 3%
  2. Articaine 4% Correct answer.
  3. Prilocaine 4%
  4. Bupivacaine 0.5%

Explanation

Post-marketing reports and registry data link 4% articaine, particularly when used for inferior alveolar blocks, to a disproportionate share of persistent paresthesia cases. Its higher concentration and greater lipid solubility are proposed contributors.

Question 45Oral and Maxillofacial Surgery and Pain Control

A 4-mm oroantral communication is noted immediately after extraction of a maxillary first molar. What is the most appropriate initial management?

  1. Place a figure-eight suture and advise against nose blowing Correct answer.
  2. Place the patient on positive-pressure nasal ventilation overnight
  3. Refer at once for surgical closure with a buccal fat pad flap
  4. Leave the socket undisturbed and give no additional instructions

Explanation

Small communications often heal spontaneously if the socket is protected and sinus pressure is avoided. A figure-eight or mattress suture stabilizes the clot, and the patient should be instructed not to blow the nose, sneeze with the mouth closed, or drink through a straw.

Question 46Oral and Maxillofacial Surgery and Pain Control

How is a Le Fort I fracture best described?

  1. A horizontal fracture above the tooth apices through the maxilla Correct answer.
  2. A pyramidal fracture extending through the nasal bridge and medial orbital walls
  3. Complete separation of the facial skeleton from the cranial base
  4. A fracture confined to the zygomatic complex and arch

Explanation

A Le Fort I is a low transverse fracture that passes above the apices of the maxillary teeth through the nasal septum and pterygoid plates, separating the tooth-bearing maxilla from the upper midface. It is the lowest of the three Le Fort levels.

Question 47Oral and Maxillofacial Surgery and Pain Control

Which maneuver is used to reduce an acute anterior dislocation of the temporomandibular joint?

  1. Downward and posterior pressure on the mandible with the thumbs on the molars Correct answer.
  2. Upward and anterior traction applied at the point of the chin
  3. Lateral manipulation of the condyle while the teeth are clenched
  4. Forward traction on the mandible while the patient opens maximally

Explanation

With the patient seated and the mandible stabilized, the clinician places thumbs on the occlusal surfaces of the molars and applies steady downward then posterior force. This disengages the condyle from the eminence and allows it to seat back into the fossa.

Question 48Oral and Maxillofacial Surgery and Pain Control

Thirty minutes after placement of a gauze pack, a patient continues to ooze from an extraction socket. What is the most appropriate next step?

  1. Discharge the patient with instructions to return if bleeding persists
  2. Administer intravenous vitamin K immediately
  3. Suture the socket without inspecting for a bleeding source
  4. Reposition moist gauze with firm biting pressure for 20 to 30 minutes Correct answer.

Explanation

Most post-extraction bleeding is controlled by sustained local pressure that allows a stable clot to form. Moist gauze replaced directly over the socket with firm biting pressure for 20 to 30 minutes should be attempted before advancing to sutures, hemostatic agents, or systemic evaluation.

Question 49Oral and Maxillofacial Surgery and Pain Control

A patient who takes propranolol requires a local anesthetic containing epinephrine. What is the principal concern?

  1. Rapid hepatic metabolism of the amide local anesthetic
  2. Immediate anaphylaxis to the vasoconstrictor
  3. Hypertension with reflex bradycardia from unopposed alpha activity Correct answer.
  4. Profound hypotension resulting from unopposed beta-receptor blockade

Explanation

Nonselective beta blockade prevents the beta-mediated vasodilation and tachycardia that normally offset epinephrine's alpha vasoconstriction. The result is an exaggerated pressor response with reflex bradycardia, so the smallest effective dose of vasoconstrictor should be used.

Question 50Oral and Maxillofacial Surgery and Pain Control

A mandibular third molar is lost during elevation, cannot be located in the mouth, and the patient is coughing. What is the most appropriate immediate action?

  1. Reassure the patient and complete the restorative appointment as planned
  2. Perform the Heimlich maneuver immediately regardless of symptoms
  3. Protect the airway and obtain chest and abdominal radiographs Correct answer.
  4. Prescribe a course of antibiotics and recheck the patient in one week

Explanation

A missing tooth may have been swallowed or aspirated, and coughing suggests airway involvement. The patient should be positioned to protect the airway while chest and abdominal radiographs localize the object; bronchoscopy is required if it lies in the respiratory tract.