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Iran OMFS Board Exam study materials
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Iran OMFS Board Exam practice questions

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Question 1Dentoalveolar Surgery and Exodontia

During extraction of a maxillary third molar, which local anesthetic injection most directly risks depositing solution into the pterygoid venous plexus if the needle is advanced too far posteriorly?

  1. Posterior superior alveolar nerve block Correct answer.
  2. Greater palatine nerve block
  3. Infraorbital nerve block
  4. Middle superior alveolar nerve block

Explanation

The posterior superior alveolar block targets the nerve just outside the posterior wall of the maxilla, a region where the pterygoid venous plexus lies immediately deep to the target. Over-advancement or a needle directed too far posteriorly and superiorly can enter this plexus and produce a hematoma. The other listed blocks target the palate, the mid-maxillary wall, or the anterior maxilla, where this vascular risk is not relevant.

Question 2Dentoalveolar Surgery and Exodontia

A patient reports profound numbness of the lower lip and chin but persistent pain on extraction of a mandibular first molar after an inferior alveolar nerve block. Which anatomic explanation best accounts for this?

  1. Inadequate greater palatine block
  2. Injection into the parotid capsule
  3. An accessory innervation from the mylohyoid nerve supplying the molar Correct answer.
  4. Failure to anesthetize the buccal nerve

Explanation

The mylohyoid nerve can carry accessory sensory fibers to mandibular molars, so lip numbness confirms a successful inferior alveolar block while the tooth remains partly innervated. Buccal nerve anesthesia affects cheek mucosa, not the tooth itself. Parotid deposition causes facial palsy, and the greater palatine nerve is irrelevant to mandibular teeth.

Question 3Dentoalveolar Surgery and Exodontia

Which tooth is most frequently the site of a maxillary sinus perforation during routine extraction because of its close proximity to the sinus floor?

  1. Maxillary canine
  2. Maxillary first molar Correct answer.
  3. Mandibular first molar
  4. Maxillary central incisor

Explanation

The maxillary first molar roots lie closest to the sinus floor and are the teeth most often associated with oroantral communication during extraction. The incisors and canine are anterior and their apices are far from the sinus. The mandibular first molar has no relationship to the maxillary sinus.

Question 4Dentoalveolar Surgery and Exodontia

A 45-year-old has a buccal exostosis overlying the roots of the maxillary premolars that interferes with flap reflection. What is the most appropriate intraoperative management?

  1. Reduce the exostosis with a bone rongeur or bur before flap adaptation Correct answer.
  2. Abandon the procedure and refer for orthodontic treatment
  3. Place the flap and close with tension over the prominence
  4. Incise directly through the exostosis to gain access

Explanation

Bony prominences that prevent tension-free flap adaptation should be reduced intraoperatively with a rongeur or rotary instrument to allow passive closure. Closing under tension over an unreduced exostosis risks dehiscence and flap necrosis. Orthodontic referral and incising through bone do not address the mechanical problem.

Question 5Dentoalveolar Surgery and Exodontia

Which radiographic finding on a panoramic image most strongly suggests that a mandibular third molar will require a more demanding surgical approach?

  1. Presence of a small carious lesion on the occlusal surface
  2. Eruption to the occlusal plane with a single conical root
  3. Horizontal impaction with the crown beneath the distal root of the second molar Correct answer.
  4. Vertical angulation with complete crown exposure

Explanation

Horizontal impaction with the crown positioned under the distal contour of the adjacent second molar requires bone removal and often sectioning, increasing surgical difficulty. A fully erupted conical-rooted tooth and a vertically angulated exposed crown are straightforward. Occlusal caries does not by itself alter surgical difficulty.

Question 6Dentoalveolar Surgery and Exodontia

After a difficult mandibular third molar extraction, a patient develops persistent anesthesia of the lower lip and chin. Which nerve injury pattern is most consistent with this presentation?

  1. Mylohyoid nerve injury in the submandibular space
  2. Long buccal nerve injury at the retromolar pad
  3. Inferior alveolar nerve injury distal to the lingual branch point Correct answer.
  4. Lingual nerve injury at the lingual plate

Explanation

The inferior alveolar nerve supplies the lower lip and chin, so anesthesia in that distribution indicates injury along its course. Lingual nerve injury produces tongue numbness and taste disturbance. Long buccal injury affects buccal gingiva, and mylohyoid injury does not cause lip anesthesia.

Question 7Dentoalveolar Surgery and Exodontia

Which condition is an absolute contraindication to the immediate placement of a dental implant into a fresh extraction socket?

  1. Patient taking a low-dose aspirin regimen
  2. Active acute purulent infection at the site Correct answer.
  3. Socket with intact four-wall bony architecture
  4. History of well-controlled hypertension

Explanation

Acute purulent infection at the site compromises osseointegration and healing and is considered an absolute contraindication to immediate implant placement. An intact four-wall socket is favorable anatomy. Low-dose aspirin and controlled hypertension are not absolute contraindications and are managed individually.

Question 8Dentoalveolar Surgery and Exodontia

A patient on long-term warfarin with an INR of 3.8 requires extraction of a periodontally hopeless tooth. What is the most appropriate preoperative step?

  1. Substitute a direct oral anticoagulant without physician input
  2. Consult the prescribing physician to adjust anticoagulation and recheck INR Correct answer.
  3. Double the warfarin dose the night before surgery
  4. Proceed immediately and place a pressure pack afterward

Explanation

An INR of 3.8 exceeds the range generally considered acceptable for routine dentoalveolar surgery, so the prescribing physician should be consulted to adjust therapy and recheck the value. Proceeding carries a serious bleeding risk, and altering anticoagulation without physician input is unsafe. Substituting medications is a physician decision, not a dental one.

Question 9Dentoalveolar Surgery and Exodontia

Which suture technique is most appropriate for achieving primary closure of a socket after a surgical extraction where the buccal flap is under mild tension?

  1. Continuous locking sutures with wide bites
  2. Simple interrupted sutures tied tightly to compress the tissue
  3. Figure-of-eight suture around the adjacent tooth
  4. Interrupted sutures placed to approximate the flap margins without blanching Correct answer.

Explanation

Interrupted sutures that approximate the margins without blanching the tissue provide reliable closure while preserving perfusion. Tightly tied sutures cause ischemia and dehiscence. Continuous locking sutures with wide bites are unnecessary here, and a figure-of-eight around an adjacent tooth does not close the socket.

Question 10Dentoalveolar Surgery and Exodontia

Which is the most common complication following surgical removal of a mandibular third molar?

  1. Mandibular fracture
  2. Permanent inferior alveolar nerve injury
  3. Postoperative swelling and pain Correct answer.
  4. Osteomyelitis of the mandible

Explanation

Postoperative swelling and pain are the most common sequelae of surgical third molar removal and are expected in the normal healing course. Mandibular fracture, permanent nerve injury, and osteomyelitis are serious but uncommon complications.

Question 11Dentoalveolar Surgery and Exodontia

A patient develops a dry socket on the third postoperative day after mandibular molar extraction. What is the most appropriate initial management?

  1. Irrigate the socket and place a medicated dressing Correct answer.
  2. Immediately place a bone graft into the socket
  3. Prescribe systemic antibiotics alone without local care
  4. Curette the socket vigorously to induce bleeding

Explanation

Alveolar osteitis is managed by gentle irrigation to remove debris and placement of a medicated dressing for pain control and healing. Vigorous curettage can further traumatize the socket. Antibiotics alone do not address the local problem, and grafting is not indicated in an infected or symptomatic socket.

Question 12Dentoalveolar Surgery and Exodontia

Which clinical feature most reliably distinguishes a simple odontoma from a compound odontoma?

  1. Simple odontomas contain multiple small tooth-like structures
  2. Compound odontomas contain multiple tooth-like denticles Correct answer.
  3. Compound odontomas occur only in the mandible
  4. Simple odontomas are always associated with an impacted tooth

Explanation

Compound odontomas are characterized by multiple small tooth-like denticles, whereas simple odontomas consist of an irregular mass of dental hard tissue. Location and association with impaction are not reliable discriminating features.

Question 13Dentoalveolar Surgery and Exodontia

A 30-year-old presents with a firm, fluctuant swelling in the submandibular region following a lower molar infection. Which fascial space is most likely involved?

  1. Submental space
  2. Submandibular space Correct answer.
  3. Buccal space
  4. Canine space

Explanation

Mandibular molar infections typically spread to the submandibular space via the lingual or buccal cortex. The submental space is involved with anterior mandibular teeth, the buccal space with maxillary premolars, and the canine space with maxillary canines.

Question 14Dentoalveolar Surgery and Exodontia

Which statement best describes the rationale for using a lingual retractor during surgical extraction of a mandibular third molar?

  1. It stabilizes the tongue during extraction
  2. It provides direct retraction of the buccal flap
  3. It protects the lingual nerve and mucosa from injury during instrumentation Correct answer.
  4. It improves visibility of the maxillary tuberosity

Explanation

A lingual retractor shields the lingual nerve and mucosa from bur or elevator contact during third molar surgery. Buccal flap retraction requires a different instrument, tongue stabilization is not the purpose, and maxillary tuberosity visibility is unrelated to mandibular surgery.

Question 15Dentoalveolar Surgery and Exodontia

A patient reports prolonged bleeding after extraction despite pressure. Which laboratory test is most appropriate to screen for a platelet-related bleeding disorder?

  1. Complete blood count with platelet count Correct answer.
  2. Activated partial thromboplastin time alone
  3. Liver function tests
  4. Prothrombin time alone

Explanation

A complete blood count with platelet count screens for thrombocytopenia and other hematologic abnormalities contributing to bleeding. Prothrombin time and aPTT assess coagulation factors rather than platelet number, and liver function tests are not a first-line screen for platelet disorders.

Question 16Dentoalveolar Surgery and Exodontia

Which is the most appropriate first step in managing a patient who develops syncope during an extraction while seated in the dental chair?

  1. Perform immediate chest compressions
  2. Place the patient supine with legs elevated and ensure airway patency Correct answer.
  3. Administer intramuscular epinephrine immediately
  4. Give oral glucose without assessing consciousness

Explanation

Syncope from transient cerebral hypoperfusion is managed by placing the patient supine with legs elevated to improve venous return and ensuring airway patency. Epinephrine and chest compressions are reserved for anaphylaxis and cardiac arrest, respectively. Oral glucose is inappropriate without assessing consciousness and airway safety.

Question 17Dentoalveolar Surgery and Exodontia

Which factor most increases the risk of mandibular fracture during surgical removal of an impacted third molar?

  1. A fully erupted tooth with a conical root
  2. Placement of a single interrupted suture
  3. Extensive bone removal and a deeply impacted tooth Correct answer.
  4. Use of copious irrigation during drilling

Explanation

Extensive bone removal and deep impaction require greater force and create stress concentrations that increase fracture risk. A fully erupted conical-rooted tooth is low risk, and irrigation and suturing do not contribute to fracture.

Question 18Dentoalveolar Surgery and Exodontia

A patient has a mandibular second molar with severe periodontal bone loss and mobility. Which treatment option is most appropriate when the adjacent first molar is sound?

  1. Intentional replantation of the second molar
  2. Immediate autotransplantation of the second molar
  3. Root resection of the first molar
  4. Extraction with socket preservation and consideration of a fixed partial denture or implant Correct answer.

Explanation

A severely mobile periodontally involved molar with inadequate support is generally extracted, and the site may be preserved for future implant or fixed prosthodontic rehabilitation. Autotransplantation, root resection of a sound adjacent tooth, and intentional replantation do not address the hopeless prognosis.

Question 19Dentoalveolar Surgery and Exodontia

Which anatomic structure is most at risk during elevation of a maxillary canine that is deeply impacted palatally?

  1. Greater palatine neurovascular bundle Correct answer.
  2. Mylohyoid nerve
  3. Inferior alveolar nerve
  4. Lingual nerve

Explanation

A palatally impacted maxillary canine lies near the greater palatine neurovascular bundle, which can be injured during palatal flap elevation or bone removal. The inferior alveolar, lingual, and mylohyoid nerves are all mandibular structures.

Question 20Dentoalveolar Surgery and Exodontia

Which of the following best explains why a mandibular block may fail to anesthetize the buccal soft tissue during a third molar extraction?

  1. The buccal nerve is not anesthetized by the inferior alveolar block Correct answer.
  2. The mylohyoid nerve blocks the buccal nerve
  3. The masseteric nerve provides buccal sensation
  4. The lingual nerve is anesthetized by the inferior alveolar block

Explanation

The buccal nerve (long buccal) is a separate branch of the mandibular division and is not anesthetized by the inferior alveolar block, so a separate buccal infiltration is needed. The lingual nerve is anesthetized in the standard block, the mylohyoid nerve does not block the buccal nerve, and the masseteric nerve is motor to the masseter.

Question 21Dentoalveolar Surgery and Exodontia

A patient with a history of bisphosphonate therapy for osteoporosis requires extraction of a mandibular molar. Which step is most appropriate before surgery?

  1. Immediately place a bone graft at the time of extraction
  2. Proceed without any additional assessment
  3. Perform a wide en bloc resection of the mandible
  4. Assess cumulative exposure and drug holiday status in consultation with the prescribing physician Correct answer.

Explanation

Patients with bisphosphonate exposure require assessment of cumulative dose, route, and duration, along with physician consultation to evaluate medication-related osteonecrosis of the jaw risk. Proceeding without assessment, immediate grafting, and en bloc resection are not appropriate first steps.

Question 22Dentoalveolar Surgery and Exodontia

Which of the following is the most appropriate method for controlling hemorrhage from a branch of the greater palatine artery after a palatal flap procedure?

  1. Apply direct pressure and suture ligation or electrocautery at the bleeding point Correct answer.
  2. Prescribe oral tranexamic acid alone
  3. Apply ice to the contralateral cheek
  4. Pack the socket with a collagen sponge

Explanation

Palatal hemorrhage is controlled by identifying the bleeding vessel and applying direct pressure with suture ligation or electrocautery. Socket packing is for alveolar bleeding, systemic tranexamic acid alone does not address an identifiable vessel, and ice to the cheek is ineffective for palatal bleeding.

Question 23Dentoalveolar Surgery and Exodontia

Which statement about the healing of an extraction socket is correct?

  1. The socket remains a persistent defect indefinitely
  2. Epithelialization begins within the first week and bone fill continues for several months Correct answer.
  3. Epithelialization begins only after six months
  4. Bone fill is complete within two weeks

Explanation

After extraction, epithelialization begins within days and progresses over the first week or two, while bone fill proceeds over several months. Bone fill is not complete within two weeks, and the socket does not remain a persistent defect.

Question 24Dentoalveolar Surgery and Exodontia

A patient presents with trismus and dysphagia three days after a mandibular molar extraction. Which diagnosis should be considered first?

  1. Normal postoperative swelling
  2. Temporomandibular joint dislocation
  3. Spread of odontogenic infection into the masticator and submandibular spaces Correct answer.
  4. Simple alveolar osteitis

Explanation

Trismus with dysphagia after extraction suggests spread of infection into the masticator and submandibular spaces, requiring urgent evaluation and airway assessment. Alveolar osteitis causes localized pain without trismus or dysphagia, normal swelling does not cause dysphagia, and TMJ dislocation presents differently.

Question 25Oral and Maxillofacial Pathology

A 24-year-old woman presents with a 1.5 cm fluctuant swelling at the midline of the lower labial mucosa that fluctuates in size and empties when pressure is applied, then refills with clear viscous fluid. Which lesion is most consistent with this presentation?

  1. Lipoma
  2. Mucocele (extravasation phenomenon) Correct answer.
  3. Fibroma
  4. Hemangioma

Explanation

A painless fluctuant nodule of the lower lip that fluctuates in size and discharges clear viscous fluid after minor trauma is the classic presentation of a mucocele, which represents extravasated salivary mucin surrounded by granulation tissue. The lower lip is the most common site because of abundant minor salivary glands and frequent biting trauma.

Question 26Oral and Maxillofacial Pathology

Which odontogenic cyst arises from the rests of Malassez in the periodontal ligament and is most often found at the apex of a non-vital tooth?

  1. Odontogenic keratocyst
  2. Lateral periodontal cyst
  3. Dentigerous cyst
  4. Radicular cyst Correct answer.

Explanation

The radicular (periapical) cyst develops from epithelial rests of Malassez in the periodontal ligament after inflammatory stimulation from a necrotic pulp, and it is the most common odontogenic cyst. It presents as a periapical radiolucency associated with a non-vital tooth.

Question 27Oral and Maxillofacial Pathology

Which condition is characterized by multiple recurrent aphthous-like ulcers, genital ulceration, and uveitis, and is diagnosed clinically using the criteria of recurrent oral and genital aphthae plus ocular or cutaneous lesions?

  1. Lichen planus
  2. Behçet disease Correct answer.
  3. Pemphigus vulgaris
  4. Erythema multiforme

Explanation

Behçet disease is a systemic vasculitis defined by recurrent oral aphthae plus two of genital aphthae, ocular lesions, skin lesions, or a positive pathergy test. The oral ulcers are typically indistinguishable from ordinary recurrent aphthous stomatitis, so the systemic findings establish the diagnosis.

Question 28Oral and Maxillofacial Pathology

A 60-year-old man has a painless, firm, non-tender submandibular mass. Fine-needle aspiration suggests a low-grade malignancy. Which salivary gland tumor is the most common malignancy of the submandibular gland?

  1. Adenoid cystic carcinoma Correct answer.
  2. Pleomorphic adenoma
  3. Mucoepidermoid carcinoma
  4. Warthin tumor

Explanation

Adenoid cystic carcinoma is the most frequent malignant tumor of the submandibular gland and is notorious for perineural invasion and late distant metastasis despite slow growth. Its cribriform 'Swiss cheese' pattern is characteristic histologically.

Question 29Oral and Maxillofacial Pathology

Which histologic feature best distinguishes an odontogenic keratocyst from other odontogenic cysts?

  1. A thick non-keratinized lining with mucous cells and Rushton bodies
  2. A thin parakeratinized epithelial lining with a corrugated surface and palisaded basal cells Correct answer.
  3. Stratified squamous epithelium with prominent rete ridges and cholesterol clefts
  4. Ciliated columnar epithelium with goblet cells

Explanation

The odontogenic keratocyst is defined by a uniform thin epithelial lining with a corrugated parakeratinized surface and a palisaded, hyperchromatic basal layer, often with satellite cysts in the wall. These features explain its high recurrence rate and association with the PTCH1 gene and nevoid basal cell carcinoma syndrome.

Question 30Oral and Maxillofacial Pathology

A patient reports burning mouth symptoms that worsen through the day, with a smooth erythematous tongue and angular cheilitis. Which nutritional deficiency most commonly produces this triad?

  1. Vitamin B12 deficiency Correct answer.
  2. Iron excess (hemochromatosis)
  3. Vitamin C deficiency
  4. Vitamin D deficiency

Explanation

Vitamin B12 deficiency causes megaloblastic anemia with glossitis, a smooth beefy-red tongue, angular cheilitis, and burning mouth, often with paresthesias. Folate deficiency produces a similar picture, and both are important reversible causes of oral burning.

Question 31Oral and Maxillofacial Pathology

Which of the following is the most important prognostic factor in oral squamous cell carcinoma?

  1. Tumor histologic grade alone
  2. Patient's blood group
  3. Pathologic stage, especially nodal metastasis Correct answer.
  4. Presence of leukoplakia

Explanation

Pathologic stage, particularly the presence and extent of cervical lymph node metastasis, is the strongest predictor of survival in oral squamous cell carcinoma. Histologic grade correlates poorly with outcome and is secondary to stage.

Question 32Oral and Maxillofacial Pathology

A 35-year-old woman has bilateral painful erosions of the buccal mucosa and gingiva. Biopsy shows intraepithelial separation with acantholysis, and direct immunofluorescence shows intercellular IgG in a chicken-wire pattern. What is the diagnosis?

  1. Linear IgA disease
  2. Mucous membrane pemphigoid
  3. Bullous pemphigoid
  4. Pemphigus vulgaris Correct answer.

Explanation

Pemphigus vulgaris shows suprabasal acantholysis with intraepithelial clefting and intercellular IgG deposition in a net-like pattern on direct immunofluorescence. Oral lesions are often the first manifestation and may precede skin blistering.

Question 33Oral and Maxillofacial Pathology

Which radiographic appearance is most characteristic of an ameloblastoma?

  1. Sunburst periosteal reaction with cortical destruction
  2. Unilocular radiolucency around the crown of an impacted tooth only
  3. Ground-glass radiopacity of the maxilla
  4. Multilocular soap-bubble radiolucency in the posterior mandible Correct answer.

Explanation

Ameloblastoma typically presents as a multilocular radiolucency with a soap-bubble or honeycomb pattern in the posterior mandible, often causing root resorption and cortical expansion. It is locally aggressive and requires resection with margins.

Question 34Oral and Maxillofacial Pathology

A 50-year-old man has a smooth, non-ulcerated, dome-shaped palatal swelling that is firm and slightly bluish. Biopsy shows a mass of minor salivary gland tissue with ducts and acini. What is the diagnosis?

  1. Nasopalatine duct cyst
  2. Pleomorphic adenoma Correct answer.
  3. Palatal abscess
  4. Mucoepidermoid carcinoma

Explanation

Pleomorphic adenoma is the most common benign salivary gland tumor and frequently arises in the minor glands of the palate, presenting as a firm, smooth, non-ulcerated swelling. It contains mixed epithelial and myxochondroid elements and requires complete excision because of recurrence risk.

Question 35Oral and Maxillofacial Pathology

Which of the following is the most common site of oral leukoplakia that carries the highest risk of malignant transformation?

  1. Hard palate
  2. Floor of the mouth and lateral tongue Correct answer.
  3. Dorsum of the tongue
  4. Attached gingiva

Explanation

Leukoplakia at high-risk sites such as the floor of the mouth, lateral tongue, and retromolar region has a greater likelihood of dysplasia and malignant transformation than lesions on low-risk keratinized sites. Non-homogeneous lesions, especially with erythroplakia, carry the highest risk.

Question 36Oral and Maxillofacial Pathology

A 30-year-old woman has multiple small, yellow-white papules on the buccal mucosa and lower lip that are asymptomatic. Biopsy shows collections of sebaceous glands without hair follicles. What is the diagnosis?

  1. White sponge nevus
  2. Lichen planus
  3. Fordyce granules Correct answer.
  4. Leukoedema

Explanation

Fordyce granules are ectopic sebaceous glands that appear as multiple small yellow-white papules on the buccal mucosa, lips, and retromolar area. They are a normal anatomic variant and require no treatment.

Question 37Oral and Maxillofacial Pathology

Which statement about the pathogenesis of oral candidiasis is most accurate?

  1. It is a premalignant epithelial dysplasia
  2. It results from an overgrowth of Candida albicans favored by local or systemic immunosuppression Correct answer.
  3. It is caused by a DNA virus that infects basal keratinocytes
  4. It is an autoimmune reaction against desmosomal proteins

Explanation

Oral candidiasis is an opportunistic infection by Candida albicans that occurs when local defenses are altered, such as by denture wearing, xerostomia, antibiotic or corticosteroid use, diabetes, or immunosuppression. It is not a viral, autoimmune, or dysplastic process.

Question 38Oral and Maxillofacial Pathology

A patient with a history of a recent herpes labialis lesion develops multiple small vesicles on the hard palate and gingiva. Which feature best distinguishes recurrent intraoral herpes from recurrent aphthous stomatitis?

  1. Bilateral ulcers associated with genital lesions
  2. A single large ulcer persisting for more than six weeks
  3. Vesicles that rupture to form clustered erosions on keratinized mucosa Correct answer.
  4. Round ulcers with a yellow pseudomembrane on non-keratinized mucosa

Explanation

Recurrent intraoral herpes simplex presents as clustered vesicles that rupture into small erosions on keratinized mucosa such as the hard palate and attached gingiva. Recurrent aphthous stomatitis instead produces round ulcers with a yellow pseudomembrane on non-keratinized mucosa.

Question 39Oral and Maxillofacial Pathology

Which of the following is the most appropriate initial management for an oral mucocele of the lower lip that has persisted for several months?

  1. Radiation therapy
  2. Systemic corticosteroids
  3. Excisional biopsy or laser removal Correct answer.
  4. Observation for spontaneous resolution

Explanation

Persistent mucoceles are treated by complete surgical excision or laser ablation, which also provides histologic confirmation. Simple observation is reasonable only for small, recent lesions, and systemic or radiation therapy is inappropriate for a benign lesion.

Question 40Oral and Maxillofacial Pathology

A 45-year-old man has a painless, hard, fixed submandibular lymph node and a firm ulcerated lesion on the floor of the mouth. Which diagnostic step is most appropriate for establishing the diagnosis?

  1. Incisional biopsy of the oral lesion Correct answer.
  2. Excisional biopsy of the lymph node alone
  3. Fine-needle aspiration of the node without evaluating the primary site
  4. Observation with repeat examination in six months

Explanation

A persistent ulcerated floor-of-mouth lesion with a fixed neck node is highly suspicious for oral squamous cell carcinoma, and incisional biopsy of the primary lesion provides the diagnosis and grade. Evaluation of the neck is by imaging and fine-needle aspiration, but the primary site should be biopsied.

Question 41Oral and Maxillofacial Pathology

Which condition is characterized by a diffuse, milky-white, filmy appearance of the buccal mucosa that disappears when the mucosa is stretched?

  1. White sponge nevus
  2. Candidiasis
  3. Leukoplakia
  4. Leukoedema Correct answer.

Explanation

Leukoedema is a common benign variant in which the buccal mucosa shows a diffuse milky-white film that fades when the tissue is stretched. It is not a premalignant lesion and requires no treatment.

Question 42Oral and Maxillofacial Pathology

A 20-year-old man has a unilocular radiolucency at the apex of a non-vital mandibular first molar. Histology shows a cyst lined by non-keratinized stratified squamous epithelium with cholesterol clefts and hemosiderin. What is the diagnosis?

  1. Odontogenic keratocyst
  2. Radicular cyst Correct answer.
  3. Ameloblastoma
  4. Dentigerous cyst

Explanation

A radicular cyst is a periapical inflammatory cyst lined by non-keratinized stratified squamous epithelium, often with cholesterol clefts, hemosiderin, and Rushton bodies. It is associated with a non-vital tooth and is the most common odontogenic cyst.

Question 43Oral and Maxillofacial Pathology

Which of the following best explains why ameloblastoma has a high recurrence rate after conservative curettage?

  1. Tumor islands infiltrate cancellous bone beyond the radiographic margin Correct answer.
  2. It metastasizes early to cervical lymph nodes
  3. It is a virus-induced lesion with multifocal spread
  4. It is a self-limiting hamartoma

Explanation

Ameloblastoma is locally aggressive, and microscopic tumor islands extend into cancellous bone beyond the apparent radiographic margin, so simple curettage leaves residual tumor and leads to recurrence. This is why segmental resection with margins is preferred for many lesions.

Question 44Oral and Maxillofacial Pathology

A 55-year-old woman has bilateral, symmetric white striae on the buccal mucosa with erosive areas. Biopsy shows a band-like lymphocytic infiltrate at the epithelial-connective tissue interface with basal cell degeneration. What is the diagnosis?

  1. Lupus erythematosus
  2. Candidiasis
  3. Oral lichen planus Correct answer.
  4. Leukoedema

Explanation

Oral lichen planus classically shows bilateral white reticular striae with a band-like subepithelial lymphocytic infiltrate and basal cell liquefactive degeneration. It is considered a potentially malignant disorder, so long-term follow-up is required.

Question 45Oral and Maxillofacial Pathology

Which of the following best describes the radiographic and clinical features of fibrous dysplasia of the jaws?

  1. Sunburst periosteal reaction with cortical destruction
  2. Punched-out radiolucency at the periapical region of a non-vital tooth
  3. Ground-glass radiopacity with blending into surrounding bone and facial asymmetry Correct answer.
  4. Well-defined multilocular radiolucency with root resorption

Explanation

Fibrous dysplasia produces a ground-glass or orange-peel radiopacity that blends gradually into surrounding bone, often with unilateral facial enlargement and displacement of teeth. It is a benign fibro-osseous lesion that stabilizes after puberty.

Question 46Oral and Maxillofacial Pathology

A 65-year-old man has a rapidly growing, painful swelling of the posterior mandible with paresthesia of the lower lip. Radiographs show an ill-defined radiolucency with cortical destruction and a sunburst periosteal reaction. What is the most likely diagnosis?

  1. Ameloblastoma
  2. Fibrous dysplasia
  3. Dentigerous cyst
  4. Osteosarcoma of the jaw Correct answer.

Explanation

Rapid growth, pain, lip paresthesia, ill-defined bone destruction, and a sunburst periosteal reaction are features of a malignant bone tumor such as osteosarcoma. Urgent biopsy and imaging are required.

Question 47Oral and Maxillofacial Pathology

Which of the following is the most common intraoral site for squamous cell carcinoma?

  1. Lateral border of the tongue and floor of the mouth Correct answer.
  2. Attached gingiva
  3. Buccal mucosa
  4. Hard palate

Explanation

The lateral border of the tongue and floor of the mouth are the most common intraoral sites for squamous cell carcinoma, partly because saliva pools there and these areas are exposed to carcinogens. These sites also drain to the submandibular and upper cervical nodes.

Question 48Oral and Maxillofacial Pathology

A patient with a known history of a dentigerous cyst around an impacted mandibular third molar now has a rapidly enlarging mass with cortical expansion and a solid component on imaging. Which transformation should be suspected?

  1. Spontaneous regression of the cyst
  2. Development of a radicular cyst
  3. Formation of a nasopalatine duct cyst
  4. Ameloblastic transformation within the cyst lining Correct answer.

Explanation

Dentigerous cysts can undergo neoplastic transformation of their epithelial lining, most often to ameloblastoma or, less commonly, to mucoepidermoid carcinoma or squamous cell carcinoma. Rapid enlargement with a solid component or cortical breakthrough should prompt biopsy.

Question 49Trauma and Maxillofacial Injuries

A 25-year-old man has a unilateral mandibular angle fracture with an unfavorable vertical fracture line. Which muscle group primarily displaces the proximal segment medially and superiorly?

  1. Lateral pterygoid and digastric on the contralateral side
  2. Mylohyoid and geniohyoid acting on the distal fragment
  3. Medial pterygoid and masseter on the ipsilateral side Correct answer.
  4. Temporalis and buccinator acting on the coronoid process

Explanation

In an unfavorable angle fracture, the proximal (posterior) segment is pulled medially by the medial pterygoid and superiorly by the masseter, both on the same side as the fracture. The distal fragment tends to be displaced medially and inferiorly by the mylohyoid and anterior digastric. Understanding these vectors guides the direction of fixation and reduction.

Question 50Trauma and Maxillofacial Injuries

Which clinical finding most strongly suggests a fracture of the zygomaticomaxillary complex rather than an isolated orbital blowout fracture?

  1. Positive forced duction test on the affected eye
  2. Step deformity at the infraorbital rim with malar depression Correct answer.
  3. Subconjunctival hemorrhage limited to the lateral sclera
  4. Periorbital ecchymosis appearing 24 hours after injury

Explanation

A palpable step at the infraorbital rim together with flattening of the malar prominence reflects disruption of the zygomaticomaxillary sutures and is characteristic of a ZMC fracture. Periorbital ecchymosis and subconjunctival hemorrhage are nonspecific and occur in both injury patterns. Forced duction abnormality indicates muscle entrapment, which is more typical of blowout fractures.