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Kuwait MOH Dentist (KDLE) study materials
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Kuwait MOH Dentist (KDLE) practice questions

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Question 1Oral Anatomy, Histology and Embryology

Which permanent tooth normally erupts first into the oral cavity?

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

Explanation

The mandibular first molar is typically the first permanent tooth to erupt, appearing at about 6 years of age, often just before or alongside the mandibular central incisors. It is preceded in the mouth only by the primary dentition, and its early eruption is why it is often mistaken for a primary molar.

Question 2Oral Anatomy, Histology and Embryology

Enamel rods (prisms) are oriented in which general direction relative to the dentinoenamel junction?

  1. Tangential, running only within the outer enamel layer
  2. Parallel to the junction along its full length
  3. Perpendicular to the junction, running outward toward the surface Correct answer.
  4. Randomly, with no consistent relationship

Explanation

Enamel rods extend from the dentinoenamel junction outward to the enamel surface, so they lie roughly perpendicular to the junction. Their path is not straight but undulating, and near the surface they may become more vertical. This orientation determines how enamel is prepared and etched.

Question 3Oral Anatomy, Histology and Embryology

The mandibular nerve leaves the skull through which opening?

  1. Jugular foramen
  2. Foramen rotundum
  3. Foramen ovale Correct answer.
  4. Foramen spinosum

Explanation

The mandibular division of the trigeminal nerve exits the middle cranial fossa through the foramen ovale, accompanied by the accessory meningeal artery. It then enters the infratemporal fossa, where it divides into its branches. The other listed foramina transmit different structures.

Question 4Oral Anatomy, Histology and Embryology

Which salivary gland secretion is predominantly serous and contributes most of the stimulated saliva?

  1. Labial glands
  2. Parotid gland Correct answer.
  3. Sublingual gland
  4. Palatine glands

Explanation

The parotid gland is almost entirely serous and produces the largest share of stimulated saliva, especially with chewing. Its secretion is rich in amylase and flows through Stensen's duct opposite the maxillary second molar. Minor glands such as palatine and labial glands are mostly mucous and contribute little volume.

Question 5Oral Anatomy, Histology and Embryology

During odontogenesis, the dental lamina first appears at which stage?

  1. Cap stage
  2. Bell stage
  3. Bud stage Correct answer.
  4. Apposition stage

Explanation

The dental lamina forms as a thickening of oral epithelium that grows into the underlying ectomesenchyme, marking the initiation of the bud stage. The enamel organ then invaginates to form the cap and later the bell. Apposition is a much later stage of hard tissue deposition.

Question 6Oral Anatomy, Histology and Embryology

Which cells are responsible for resorbing bone during orthodontic tooth movement?

  1. Osteoblasts
  2. Cementoblasts
  3. Osteoclasts Correct answer.
  4. Fibroblasts

Explanation

Osteoclasts are multinucleated cells of hematopoietic origin that resorb bone on the pressure side of a moving tooth. Their activity, balanced against osteoblastic deposition on the tension side, produces the net shift of the alveolus. Fibroblasts and cementoblasts do not resorb bone.

Question 7Oral Anatomy, Histology and Embryology

A patient has a tooth with two roots and two canals in the mandibular first molar. Which root most commonly contains two canals?

  1. Distal root
  2. Neither root, as the tooth is single-rooted
  3. Mesial root Correct answer.
  4. Both roots equally

Explanation

The mesial root of the mandibular first molar typically has two canals, mesiobuccal and mesiolingual, and often shows an isthmus between them. The distal root usually has one large canal, though a second distal canal occurs in a minority of teeth. This anatomy is a common cause of missed canals during endodontics.

Question 8Oral Anatomy, Histology and Embryology

Which cranial nerve provides general sensation to the anterior two-thirds of the tongue?

  1. Hypoglossal nerve
  2. Glossopharyngeal nerve
  3. Facial nerve
  4. Lingual nerve branch of the mandibular nerve Correct answer.

Explanation

General sensation from the anterior two-thirds of the tongue travels via the lingual nerve, a branch of the mandibular division of the trigeminal nerve. Taste from the same region is carried by the chorda tympani of the facial nerve. The glossopharyngeal nerve handles general sensation and taste from the posterior third.

Question 9Oral Anatomy, Histology and Embryology

Which structure separates the submandibular from the sublingual space?

  1. Mylohyoid muscle Correct answer.
  2. Buccinator muscle
  3. Geniohyoid muscle
  4. Hyoglossus muscle

Explanation

The mylohyoid muscle forms the floor of the mouth and separates the submandibular space below from the sublingual space above. The gland extends around the muscle's posterior free border, and its duct runs forward deep to mylohyoid to the sublingual papilla. This relationship explains how infection can spread between the spaces.

Question 10Oral Anatomy, Histology and Embryology

Which type of dentin is formed before completion of the apical foramen and is the bulk of the tooth's dentin?

  1. Secondary dentin
  2. Tertiary dentin
  3. Sclerotic dentin
  4. Primary dentin Correct answer.

Explanation

Primary dentin is laid down before root completion and constitutes most of the dentin thickness. Secondary dentin forms slowly throughout life after eruption, and tertiary dentin is a localized response to injury. Sclerotic dentin results from tubular obliteration with age or irritation.

Question 11Oral Anatomy, Histology and Embryology

Which tooth typically shows the most pronounced cervical line curvature on the mesial surface?

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

Explanation

The maxillary central incisor has a markedly curved cervical line mesially, reflecting the broad mesial contour of the crown. Cervical line curvature generally follows crown convexity, so teeth with flatter proximal surfaces show less curvature. This anatomy guides margin placement and crown contour.

Question 12Oral Anatomy, Histology and Embryology

Which nerve is at risk of injury during surgical removal of a mandibular third molar whose roots lie close to the mandibular canal?

  1. Chorda tympani
  2. Mylohyoid nerve
  3. Long buccal nerve
  4. Inferior alveolar nerve Correct answer.

Explanation

The inferior alveolar nerve runs in the mandibular canal, which can lie very close to the apices of mandibular third molars. Injury during extraction produces temporary or permanent lip and chin numbness. The long buccal nerve supplies the cheek mucosa and is not within the canal.

Question 13Oral Anatomy, Histology and Embryology

A developing tooth shows an enamel organ with a stratum intermedium, stellate reticulum, and a prominent cervical loop. Which stage is this?

  1. Cap stage
  2. Bud stage
  3. Bell stage Correct answer.
  4. Dental lamina stage

Explanation

The bell stage is characterized by a well-defined enamel organ with four layers, including the stratum intermedium and stellate reticulum, and a cervical loop where the inner and outer enamel epithelia meet. The bud stage lacks these layers, and the cap stage shows early invagination without full differentiation.

Question 14Oral Anatomy, Histology and Embryology

Which feature distinguishes a maxillary first molar from a maxillary second molar on examination?

  1. The second molar always has four cusps and no oblique ridge
  2. The first molar has a single root, while the second has three
  3. The second molar is larger in all dimensions
  4. The first molar usually has a cusp of Carabelli and a larger, more rhomboidal outline Correct answer.

Explanation

The maxillary first molar typically bears a cusp of Carabelli on the mesiolingual surface and has a larger, more rhomboidal crown than the second molar. The second molar is generally smaller and more compressed, and may lack the Carabelli cusp. Both teeth usually have three roots and an oblique ridge.

Question 15Oral Anatomy, Histology and Embryology

During tooth development, which structure gives rise to the periodontal ligament and cementum?

  1. Dental follicle Correct answer.
  2. Enamel organ
  3. Dental papilla
  4. Hertwig's epithelial root sheath

Explanation

The dental follicle surrounds the developing tooth and gives rise to the periodontal ligament, cementum, and alveolar bone. The dental papilla forms dentin and pulp, while the enamel organ forms enamel. Hertwig's epithelial root sheath guides root shape but does not form the ligament.

Question 16Oral Anatomy, Histology and Embryology

Which arrangement of the temporomandibular joint allows the mandible to open fully during normal function?

  1. Pure rotation in both compartments
  2. Translation in the lower compartment followed by rotation in the upper compartment
  3. Pure translation in both compartments
  4. Rotation in the lower compartment followed by translation in the upper compartment Correct answer.

Explanation

Normal opening begins with rotation of the condyle in the lower joint compartment, followed by translation of the condyle and disc together in the upper compartment. The upper compartment is the larger one and permits the sliding movement. Pure rotation or pure translation alone would not allow full opening.

Question 17Dental Anatomy and Occlusion

A permanent maxillary first molar is examined on a cast. Which cusp is the largest and most prominent on its occlusal surface?

  1. Mesiolingual cusp is small and the distobuccal cusp is largest
  2. Distolingual cusp
  3. Mesiolingual cusp Correct answer.
  4. Distobuccal cusp

Explanation

On the maxillary first molar the mesiolingual cusp is the largest and sharpest cusp, followed by the mesiobuccal cusp. The distolingual cusp is the smallest of the four main cusps, and the cusp of Carabelli, when present, is a supplemental fifth cusp on the mesiolingual surface. This size hierarchy helps distinguish the first from the second maxillary molar.

Question 18Dental Anatomy and Occlusion

During a class I occlusal relationship assessment, which tooth relationship defines the molar position?

  1. The mesiobuccal cusp of the maxillary second molar occludes in the buccal groove of the mandibular second molar
  2. The mesiobuccal cusp of the maxillary first molar occludes in the buccal groove of the mandibular first molar Correct answer.
  3. The distolingual cusp of the maxillary first molar occludes in the central fossa of the mandibular first molar
  4. The distobuccal cusp of the maxillary first molar occludes in the buccal groove of the mandibular first molar

Explanation

Angle class I is defined by the mesiobuccal cusp of the maxillary first molar resting in the buccal groove of the mandibular first molar. This relationship, together with a normal overjet and overbite, indicates a neutro-occlusion. Displacement of this cusp mesially or distally defines class II or class III respectively.

Question 19Dental Anatomy and Occlusion

Which permanent tooth normally shows the most pronounced lingual convergence of its crown when viewed from the occlusal aspect?

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

Explanation

The mandibular first premolar has a small lingual cusp and a crown that tapers strongly toward the lingual, giving marked lingual convergence. Its buccal cusp is much larger than the lingual cusp, and the occlusal outline is roughly diamond-shaped. This convergence is greater than that of the maxillary anterior teeth or the mandibular molars.

Question 20Dental Anatomy and Occlusion

A mandibular central incisor is compared with a mandibular lateral incisor. Which statement correctly describes a distinguishing feature?

  1. The central incisor is narrower mesiodistally and more symmetrical than the lateral incisor Correct answer.
  2. The lateral incisor has a perfectly symmetrical crown outline
  3. The lateral incisor is narrower mesiodistally than the central incisor
  4. The central incisor has a more distally inclined incisal edge than the lateral incisor

Explanation

The mandibular central incisor is the narrowest permanent tooth mesiodistally and has a nearly symmetrical crown. The lateral incisor is wider and its incisal edge slopes distally, reflecting the curve of the arch. These differences are used to identify each tooth in a mixed dentition.

Question 21Dental Anatomy and Occlusion

A patient's maxillary canine shows a cusp tip positioned between the mandibular canine and first premolar, with the mesiobuccal cusp of the maxillary first molar in the buccal groove. Which occlusal relationship is present?

  1. Class I canine and class I molar relationship Correct answer.
  2. Class III canine and class II molar relationship
  3. Class II canine and class I molar relationship
  4. Class II canine and class III molar relationship

Explanation

The canine relationship is class I when the maxillary canine cusp tip occludes between the mandibular canine and first premolar. Combined with the mesiobuccal cusp of the maxillary first molar in the buccal groove, the molar relationship is also class I. Both findings together describe a normal class I occlusion.

Question 22Dental Anatomy and Occlusion

During protrusive movement, which tooth contacts guide the mandible in a patient with a normal anterior coupling?

  1. The maxillary and mandibular second molars
  2. The working-side premolars
  3. The maxillary and mandibular anterior teeth Correct answer.
  4. The non-working-side molars

Explanation

In protrusive movement the mandible moves forward and the anterior teeth provide the guiding contacts, termed anterior guidance. The posterior teeth should disocclude during this movement in a normal occlusion. This separation of posterior teeth in protrusion is described by the posterior disclusion concept.

Question 23Dental Anatomy and Occlusion

A cast shows a maxillary first premolar with two roots. Which root configuration is most consistent with this finding?

  1. Three roots with a single buccal root
  2. One mesial and one distal root
  3. One buccal and one lingual root Correct answer.
  4. Two buccal roots and one lingual root

Explanation

The maxillary first premolar frequently has two roots, one buccal and one lingual, with a bifurcation near the middle or apical third. This is a characteristic feature that distinguishes it from the maxillary second premolar, which usually has a single root. Root division increases the complexity of endodontic access.

Question 24Dental Anatomy and Occlusion

In a lateral mandibular movement to the right, which teeth are considered the non-working side?

  1. The mandibular central incisors
  2. The right-side posterior teeth
  3. The left-side posterior teeth Correct answer.
  4. The maxillary central incisors

Explanation

During a right lateral excursion, the right side is the working side and the left side is the non-working side. Non-working-side contacts, if present, are often termed balancing contacts. The anterior teeth may guide the movement but are not classified as the non-working posterior segment.

Question 25Dental Anatomy and Occlusion

Which occlusal feature is characteristic of the mandibular first molar?

  1. Three buccal cusps and two lingual cusps Correct answer.
  2. Two buccal cusps and two lingual cusps only
  3. Four cusps of equal size
  4. Two buccal cusps and three lingual cusps

Explanation

The mandibular first molar typically has five cusps: three buccal (mesiobuccal, distobuccal, and distal) and two lingual (mesiolingual and distolingual). The distal cusp is the smallest and is located on the distobuccal aspect. This five-cusp pattern is a key identifier of the mandibular first molar.

Question 26Dental Anatomy and Occlusion

A clinician observes that the mesiobuccal cusp of the maxillary first molar is positioned distal to the buccal groove of the mandibular first molar. Which classification is most likely?

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

Explanation

When the mesiobuccal cusp of the maxillary first molar lies distal to the buccal groove of the mandibular first molar, the maxillary arch is positioned forward relative to the mandible, which characterizes class II. Class I would place the cusp directly in the groove, and class III would place it mesial to the groove. Class IV is not part of the standard Angle classification.

Question 27Dental Anatomy and Occlusion

Which feature best distinguishes the maxillary lateral incisor from the maxillary central incisor?

  1. A perfectly straight incisal edge with no cingulum
  2. A single straight root canal with no pulp horn
  3. A crown that is wider mesiodistally than the central incisor
  4. A more rounded crown with a deeper and more prominent cingulum and a distoincisal angle that is more rounded Correct answer.

Explanation

The maxillary lateral incisor is narrower than the central incisor and has a more rounded crown with a deeper cingulum and a more rounded distoincisal angle. Its mesioincisal angle is relatively sharper. These contours help differentiate the two anterior teeth on a cast.

Question 28Dental Anatomy and Occlusion

Which mandibular tooth most commonly has three roots?

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

Explanation

The mandibular first molar commonly has two mesial roots and one distal root, giving a three-root configuration. The mesial roots are often curved, which complicates endodontic treatment. This anatomy is a standard distinguishing feature of the mandibular first molar.

Question 29Dental Anatomy and Occlusion

In a patient with a deep overbite, which occlusal concept explains why the posterior teeth separate during mandibular protrusion?

  1. Posterior disclusion through anterior guidance Correct answer.
  2. Cusp-to-fossa intercuspation
  3. Balancing-side interference
  4. Curve of Spee flattening

Explanation

Anterior guidance causes the posterior teeth to separate during protrusive and lateral movements, a phenomenon called posterior disclusion. This protects the posterior teeth from excessive lateral forces. Balanced occlusion, by contrast, maintains posterior contacts during excursive movements.

Question 30Dental Anatomy and Occlusion

A maxillary first molar cast shows a supplemental cusp on the mesiolingual surface. What is this structure called?

  1. Lingual tubercle
  2. Cusp of Carabelli Correct answer.
  3. Distal cusp
  4. Cusp of Zuckerkandl

Explanation

The cusp of Carabelli is a supplemental fifth cusp located on the mesiolingual surface of the maxillary first molar. It is a common anatomical variant and can vary from a small pit to a prominent cusp. Its presence is a useful identifying feature of this tooth.

Question 31Oral Pathology and Oral Medicine

A 28-year-old woman presents with a 3 mm painless, fluid-filled vesicle on the lower lip that recurs at the same site several times a year and crusts within two days. Which diagnosis is most consistent with this presentation?

  1. Herpes labialis Correct answer.
  2. Actinic cheilitis
  3. Mucocele
  4. Recurrent aphthous ulcer

Explanation

Recurrent grouped vesicles at the vermilion border that rupture and crust within days represent herpes labialis, caused by reactivation of latent herpes simplex virus in the trigeminal ganglion. The short, self-limiting course and strict site recurrence are characteristic.

Question 32Oral Pathology and Oral Medicine

Which organism is the principal causative agent of acute necrotizing ulcerative gingivitis?

  1. Porphyromonas gingivalis alone
  2. Candida albicans
  3. Prevotella intermedia with fusiform bacteria and spirochetes Correct answer.
  4. Streptococcus mutans

Explanation

Acute necrotizing ulcerative gingivitis is a polymicrobial anaerobic infection in which Prevotella intermedia, fusiform bacilli and spirochetes act together, typically in a patient under stress or with poor oral hygiene. The punched-out interdental papillae with pseudomembrane and fetor oris are the clinical hallmarks.

Question 33Oral Pathology and Oral Medicine

Which clinical feature most strongly suggests a benign rather than a malignant ulcer of the oral mucosa?

  1. Fixation to underlying deep tissues
  2. Persistence beyond three weeks after irritant removal
  3. Sharp, well-defined borders with a history of trauma at the site Correct answer.
  4. Rolled everted margins with induration

Explanation

Traumatic ulcers have clean, well-demarcated borders and heal within one to two weeks once the cause is removed. Induration, rolled margins, fixation and persistence beyond three weeks are red flags that require biopsy to exclude malignancy.

Question 34Oral Pathology and Oral Medicine

Which condition is characterized by bilateral painless enlargement of the parotid glands with a dry mouth and dry eyes, and positive anti-Ro and anti-La antibodies?

  1. Sialadenosis
  2. Sialolithiasis
  3. Sjögren syndrome Correct answer.
  4. Pleomorphic adenoma

Explanation

Sjögren syndrome is an autoimmune exocrinopathy producing xerostomia, keratoconjunctivitis sicca and bilateral parotid enlargement, with anti-Ro/SSA and anti-La/SSB antibodies in most patients. The bilateral and systemic nature distinguishes it from localized salivary lesions.

Question 35Oral Pathology and Oral Medicine

A 24-year-old man has a 6 mm yellowish-white, slightly raised plaque on the buccal mucosa at the occlusal line, corresponding to a sharp cusp. It is asymptomatic and cannot be wiped off. What is the most appropriate initial management?

  1. Excisional biopsy of the lesion
  2. Removal of the mechanical irritant and review in two weeks Correct answer.
  3. Topical antifungal therapy for two weeks
  4. Systemic corticosteroids

Explanation

This is a frictional keratosis, a reactive white lesion caused by chronic low-grade mechanical trauma. Eliminating the source of friction and reassessing after two weeks is the correct first step, with biopsy reserved for lesions that persist.

Question 36Oral Pathology and Oral Medicine

Which radiographic feature is typical of an ameloblastoma of the mandible?

  1. Ground-glass opacity with loss of lamina dura
  2. Sunburst periosteal reaction
  3. Punched-out radiolucencies of the skull vault
  4. Multilocular soap-bubble radiolucency in the posterior mandible Correct answer.

Explanation

Ameloblastoma classically appears as a multilocular, soap-bubble or honeycomb radiolucency in the posterior mandible or ramus, often with root resorption. It is locally aggressive and benign in behavior in most cases.

Question 37Oral Pathology and Oral Medicine

A 45-year-old man reports a burning sensation of the tongue and buccal mucosa for three months, worse with spicy food. Examination shows no ulceration, but he has type 2 diabetes and takes a diuretic. Which diagnosis should be considered first?

  1. Erythema multiforme
  2. Burning mouth syndrome of psychological origin
  3. Secondary candidiasis related to diabetes and diuretic use Correct answer.
  4. Trigeminal neuralgia

Explanation

Diabetes mellitus and diuretic-induced xerostomia predispose to candidal overgrowth, which can present as chronic burning without visible plaques. Identifying and correcting the predisposing factors, with a trial of antifungal therapy, is the logical first step.

Question 38Oral Pathology and Oral Medicine

Which histological finding is characteristic of oral lichen planus?

  1. Periapical granuloma with foam cells
  2. Subepithelial clefting with immune deposits along the basement membrane
  3. Band-like lymphocytic infiltrate at the epithelium-connective tissue interface with saw-tooth rete ridges Correct answer.
  4. Pseudoepitheliomatous hyperplasia with atypical keratinocytes

Explanation

Oral lichen planus shows a dense band-like T-lymphocyte infiltrate hugging the basement membrane, basal cell liquefactive degeneration and saw-tooth rete ridges. These features reflect a lichenoid interface mucositis.

Question 39Oral Pathology and Oral Medicine

A 60-year-old smoker has a 2 cm painless, indurated ulcer on the lateral border of the tongue present for six weeks. What is the most appropriate next step?

  1. Start antifungal lozenges
  2. Prescribe a chlorhexidine mouthwash and review in one month
  3. Perform an incisional biopsy of the ulcer edge Correct answer.
  4. Reassure the patient that most tongue ulcers are traumatic

Explanation

An indurated ulcer persisting beyond three weeks in a smoker is highly suspicious for squamous cell carcinoma, and incisional biopsy of the indurated edge provides the diagnosis. Early biopsy avoids delay in managing a potentially curable cancer.

Question 40Oral Pathology and Oral Medicine

Which feature distinguishes a radicular cyst from a periapical granuloma?

  1. Association with a non-vital tooth
  2. Connection to the root canal
  3. Presence of a stratified squamous epithelial lining Correct answer.
  4. Presence of inflammatory cells

Explanation

Both lesions arise from a non-vital tooth and contain inflammation, but only a radicular cyst has a true epithelial lining derived from the cell rests of Malassez. The epithelial lining is the defining histological difference.

Question 41Oral Pathology and Oral Medicine

A patient with a history of recurrent aphthous stomatitis asks about the typical natural history of minor aphthae. Which statement is correct?

  1. They are 1-2 cm ulcers lasting four to six weeks
  2. They are under 1 cm, heal within 10-14 days without scarring Correct answer.
  3. They heal with scarring after six weeks
  4. They always involve the attached gingiva and palate

Explanation

Minor aphthous ulcers are smaller than 1 cm, resolve within about 10 to 14 days and heal without scarring. Major aphthae exceed 1 cm, persist for weeks and may scar.

Question 42Oral Pathology and Oral Medicine

Which clinical presentation is most typical of oral hairy leukoplakia?

  1. A painful ulcer with a pseudomembrane on the tonsil
  2. A red velvety patch on the soft palate
  3. Bilateral corrugated white plaques on the lateral borders of the tongue in an HIV-positive patient Correct answer.
  4. A solitary white patch on the floor of the mouth in a non-smoker

Explanation

Oral hairy leukoplakia is caused by Epstein-Barr virus and appears as vertical corrugated white plaques on the lateral tongue, strongly associated with HIV infection and immunosuppression. It is usually asymptomatic and cannot be wiped off.

Question 43Oral Pathology and Oral Medicine

A 35-year-old woman has sudden onset of multiple painful oral erosions with hemorrhagic crusts on the lips, plus target lesions on the hands, two weeks after starting a new antibiotic. What is the most likely diagnosis?

  1. Primary herpetic gingivostomatitis
  2. Pemphigus vulgaris
  3. Erythema multiforme Correct answer.
  4. Herpangina

Explanation

Erythema multiforme is an acute immune-mediated reaction, often triggered by infection or drugs, producing target skin lesions and hemorrhagic crusting of the lips with oral erosions. The abrupt onset after a new medication and the acral targets are classic.

Question 44Oral Pathology and Oral Medicine

Which tumor most commonly arises in the parotid gland and shows a mixture of epithelial and myxochondroid stroma on histology?

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

Explanation

Pleomorphic adenoma is the most common salivary gland tumor, most often in the parotid, and is defined by epithelial and myoepithelial cells in a myxochondroid stroma. It is benign but requires complete excision because of recurrence risk.

Question 45Oral Pathology and Oral Medicine

A 50-year-old woman presents with painful, shallow ulcers on the gingiva and hard palate. Direct immunofluorescence shows linear IgG and C3 along the basement membrane zone. Which diagnosis is most likely?

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

Explanation

Mucous membrane pemphigoid is a subepithelial autoimmune blistering disease with linear IgG and C3 deposition along the basement membrane and a predilection for gingiva and palate. The lesions are tense blisters that rupture into shallow, sometimes scar-forming erosions.

Question 46Oral Pathology and Oral Medicine

Which finding on panoramic radiography is most suggestive of an odontogenic keratocyst rather than a dentigerous cyst?

  1. Root resorption of adjacent teeth
  2. Uniform ballooning expansion of the cortex in all directions
  3. A well-defined radiolucency attached to the crown of an impacted third molar
  4. Anterior-posterior expansion greater than buccolingual expansion with a scalloped outline Correct answer.

Explanation

Odontogenic keratocysts tend to grow along the medullary cavity with minimal buccolingual expansion, producing a scalloped outline and anterior-posterior enlargement. Dentigerous cysts more typically cause uniform ballooning expansion around the crown of an unerupted tooth.

Question 47Oral Pathology and Oral Medicine

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

  1. Tumor grade alone
  2. Patient age at diagnosis
  3. Duration of symptoms before diagnosis
  4. Presence and extent of cervical lymph node metastasis Correct answer.

Explanation

Cervical lymph node metastasis, and particularly the number and level of involved nodes with extracapsular spread, is the strongest predictor of survival in oral squamous cell carcinoma. Tumor grade and symptom duration influence management but carry less prognostic weight.

Question 48Oral Pathology and Oral Medicine

A 70-year-old man develops unilateral facial paralysis, otalgia and a violaceous swelling of the parotid region. Which diagnosis should be suspected?

  1. Bell palsy
  2. Parotid abscess
  3. Sialolithiasis of the parotid duct
  4. Malignant parotid tumor with perineural invasion Correct answer.

Explanation

Facial nerve palsy with otalgia and an indurated parotid mass suggests a malignant parotid neoplasm, such as adenoid cystic carcinoma or mucoepidermoid carcinoma, invading the facial nerve. Pain and nerve deficit are red flags for malignancy in a salivary mass.

Question 49Oral Pathology and Oral Medicine

Which mechanism best explains the oral manifestations of pemphigus vulgaris?

  1. T-cell-mediated destruction of basal keratinocytes
  2. Autoantibodies against hemidesmosomal antigens causing subepithelial separation
  3. Autoantibodies against desmoglein 3 causing intraepithelial acantholysis Correct answer.
  4. Immune complex deposition in dermal vessels

Explanation

Pemphigus vulgaris is caused by IgG autoantibodies against desmoglein 3, which disrupt desmosomal adhesion and produce intraepithelial acantholysis and flaccid blisters. Oral lesions often precede skin involvement.

Question 50Oral Pathology and Oral Medicine

A patient with chronic kidney disease develops gingival overgrowth while taking ciclosporin and a calcium channel blocker. Which management approach is most appropriate initially?

  1. Topical corticosteroid application
  2. Meticulous oral hygiene with periodontal therapy and liaison with the physician about drug substitution Correct answer.
  3. Radiotherapy to the gingival tissues
  4. Immediate gingivectomy without plaque control

Explanation

Drug-induced gingival overgrowth is aggravated by plaque, and ciclosporin with a calcium channel blocker has a synergistic effect. Plaque control and periodontal debridement should come first, with discussion of alternative medication if overgrowth persists.