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EHPLE Dental Medicine study materials
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EHPLE Dental Medicine practice questions

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Question 1Oral and Maxillofacial Anatomy, Histology and Physiology

Which permanent tooth typically erupts first in the oral cavity?

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

Explanation

The mandibular first molar is usually the first permanent tooth to erupt, appearing at approximately 6 years of age, often slightly before or around the same time as the mandibular central incisor. It erupts distal to the primary second molar without replacing any deciduous tooth, which is why it is sometimes mistaken for a primary tooth. The maxillary and mandibular central incisors follow at about 6 to 7 years.

Question 2Oral and Maxillofacial Anatomy, Histology and Physiology

Enamel is formed by which cell type during amelogenesis?

  1. Fibroblast
  2. Cementoblast
  3. Ameloblast Correct answer.
  4. Odontoblast

Explanation

Ameloblasts are the specialized epithelial cells of the inner enamel epithelium that secrete the enamel matrix and later mineralize it. Odontoblasts derive from the dental papilla and form dentin, not enamel. Cementoblasts produce cementum, and fibroblasts produce the periodontal ligament.

Question 3Oral and Maxillofacial Anatomy, Histology and Physiology

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

  1. Glossopharyngeal nerve (CN IX)
  2. Lingual branch of the mandibular division of the trigeminal nerve (CN V3) Correct answer.
  3. Facial nerve (CN VII)
  4. Hypoglossal nerve (CN XII)

Explanation

General sensation (touch, temperature, pain) 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 this region is carried by the chorda tympani of the facial nerve. The glossopharyngeal nerve supplies general and taste sensation to the posterior third, and the hypoglossal nerve is motor.

Question 4Oral and Maxillofacial Anatomy, Histology and Physiology

Which salivary gland secretion is predominantly mucous and is located in the floor of the mouth beneath the tongue?

  1. Submandibular gland
  2. Minor palatal glands
  3. Parotid gland
  4. Sublingual gland Correct answer.

Explanation

The sublingual gland is a mixed gland whose secretion is predominantly mucous, and it lies in the sublingual space of the floor of the mouth. The parotid is almost entirely serous, and the submandibular is mixed but predominantly serous. Minor palatal glands are mostly mucous but are located in the palate, not the floor of the mouth.

Question 5Oral and Maxillofacial Anatomy, Histology and Physiology

Dentin is secreted initially as which unmineralized matrix?

  1. Cementoid
  2. Predentin Correct answer.
  3. Enamel matrix
  4. Osteoid

Explanation

Odontoblasts first deposit predentin, an unmineralized collagenous matrix, at the dentinoenamel junction. Predentin subsequently mineralizes to become mature dentin, leaving a thin predentin layer adjacent to the pulp throughout life. Osteoid and cementoid are matrices of bone and cementum, respectively.

Question 6Oral and Maxillofacial Anatomy, Histology and Physiology

The temporomandibular joint is best classified as which type of joint?

  1. Synovial joint with a fibrocartilaginous disc Correct answer.
  2. Fibrous synarthrosis
  3. Primary cartilaginous synchondrosis
  4. Secondary cartilaginous symphysis

Explanation

The temporomandibular joint is a synovial joint containing a fibrocartilaginous articular disc that divides it into upper and lower compartments. It is unique among synovial joints in that its articular surfaces are covered by fibrocartilage rather than hyaline cartilage. It permits both hinge (rotation) and gliding (translation) movements.

Question 7Oral and Maxillofacial Anatomy, Histology and Physiology

Which muscle elevates the mandible and is the principal muscle of mastication?

  1. Digastric
  2. Geniohyoid
  3. Lateral pterygoid
  4. Masseter Correct answer.

Explanation

The masseter is a powerful elevator of the mandible and, along with the medial pterygoid and temporalis, generates the closing force of mastication. The lateral pterygoid primarily protrudes and depresses the mandible. The digastric and geniohyoid are suprahyoid depressor muscles.

Question 8Oral and Maxillofacial Anatomy, Histology and Physiology

In a normal Class I occlusion, which tooth relationship is present?

  1. The mesiobuccal cusp of the maxillary first molar occludes mesial to the buccal groove of the mandibular first molar
  2. The mesiobuccal cusp of the maxillary first molar occludes distal to the buccal groove of the mandibular first molar
  3. The mesiobuccal cusp of the maxillary first molar occludes in the buccal groove of the mandibular first molar Correct answer.
  4. The maxillary first molar is entirely buccal to the mandibular first molar

Explanation

Angle Class I (neutrocclusion) is defined by the mesiobuccal cusp of the maxillary first molar occluding in the buccal groove of the mandibular first molar. This relationship reflects normal anteroposterior jaw position. Class II and Class III describe mesial and distal deviations of this cusp, respectively.

Question 9Oral and Maxillofacial Anatomy, Histology and Physiology

Which nerve is at risk of injury during surgical removal of an impacted mandibular third molar because it runs in the mandibular canal?

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

Explanation

The inferior alveolar nerve travels through the mandibular canal and is vulnerable to injury during removal of deeply impacted mandibular third molars, producing transient or permanent lower lip and chin anesthesia. The lingual nerve can also be injured but lies lingual to the alveolar crest rather than within the canal. The long buccal and mylohyoid nerves are less commonly implicated.

Question 10Oral and Maxillofacial Anatomy, Histology and Physiology

Which structure separates the submandibular space from the sublingual space?

  1. Mylohyoid muscle Correct answer.
  2. Digastric anterior belly
  3. Stylohyoid ligament
  4. Geniohyoid muscle

Explanation

The mylohyoid muscle forms the floor of the mouth and separates the sublingual space above it from the submandibular space below it. Infections can spread between these spaces around the posterior free border of the mylohyoid. The geniohyoid lies above the mylohyoid, and the digastric and stylohyoid ligament are not the primary dividing structure.

Question 11Oral and Maxillofacial Anatomy, Histology and Physiology

Which type of dentin forms the bulk of the tooth and contains tubules with odontoblast processes?

  1. Circumpulpal dentin Correct answer.
  2. Intertubular dentin
  3. Tertiary dentin
  4. Mantle dentin

Explanation

Circumpulpal dentin constitutes the bulk of the dentin thickness and surrounds the pulp, containing the dentinal tubules that house odontoblast processes. Mantle dentin is the thin outer layer beneath enamel, and intertubular dentin is the matrix between tubules. Tertiary dentin is reparative, formed in response to injury.

Question 12Oral and Maxillofacial Anatomy, Histology and Physiology

Which nerve provides motor innervation to the muscles of facial expression, including the orbicularis oris and buccinator?

  1. Trigeminal nerve (CN V)
  2. Facial nerve (CN VII) Correct answer.
  3. Glossopharyngeal nerve (CN IX)
  4. Accessory nerve (CN XI)

Explanation

The facial nerve supplies all muscles of facial expression through its temporal, zygomatic, buccal, marginal mandibular, and cervical branches. The trigeminal nerve provides sensation and motor supply to the muscles of mastication, not facial expression. The glossopharyngeal and accessory nerves serve other head and neck functions.

Question 13Oral and Maxillofacial Anatomy, Histology and Physiology

During swallowing, which structure prevents food from entering the nasopharynx?

  1. Soft palate Correct answer.
  2. Epiglottis
  3. Uvula
  4. Palatoglossal arch

Explanation

During the pharyngeal phase of swallowing, the soft palate elevates and tenses to seal against the posterior pharyngeal wall, preventing nasal regurgitation. The epiglottis helps protect the larynx rather than the nasopharynx. The palatoglossal arch and uvula contribute to oral and pharyngeal function but do not seal the nasopharynx.

Question 14Oral and Maxillofacial Anatomy, Histology and Physiology

Which pulp tissue component is primarily responsible for the immune defense of the dental pulp?

  1. Fibroblasts
  2. Odontoblasts
  3. Macrophages and dendritic cells Correct answer.
  4. Erythrocytes

Explanation

The dental pulp contains a resident population of macrophages and dendritic cells that recognize and process antigens, contributing to local immune defense. Odontoblasts and fibroblasts have primarily formative and structural roles. Erythrocytes are oxygen-carrying cells within the pulp vasculature and are not immune cells.

Question 15Oral and Maxillofacial Anatomy, Histology and Physiology

The mandibular condyle is located in which fossa of the temporal bone?

  1. Subarcuate fossa
  2. Mandibular fossa Correct answer.
  3. Jugular fossa
  4. Pterygoid fossa

Explanation

The mandibular condyle articulates with the mandibular fossa (glenoid fossa) of the squamous part of the temporal bone. The pterygoid fossa is a depression between the pterygoid plates, and the jugular fossa houses the jugular bulb. The subarcuate fossa is a small depression on the petrous temporal bone.

Question 16Oral and Maxillofacial Anatomy, Histology and Physiology

Which of the following best describes the arrangement of enamel rods at the dentinoenamel junction?

  1. They terminate before reaching the dentinoenamel junction
  2. They are oriented perpendicular to the dentinoenamel junction and interlock, contributing to the scalloped junction Correct answer.
  3. They are randomly oriented with no consistent pattern
  4. They run parallel to the dentinoenamel junction throughout

Explanation

Enamel rods are generally oriented perpendicular to the dentinoenamel junction, where they interdigitate and produce a scalloped interface with dentin. This interlocking improves the mechanical bond between enamel and dentin. Rods do not terminate before the junction, and their orientation is not random.

Question 17Oral and Maxillofacial Anatomy, Histology and Physiology

Which salivary gland duct opens into the oral cavity at the parotid papilla opposite the maxillary second molar?

  1. Wharton duct
  2. Rivinus duct
  3. Bartholin duct
  4. Stensen duct Correct answer.

Explanation

Stensen duct is the duct of the parotid gland and opens at the parotid papilla on the buccal mucosa opposite the maxillary second molar. Wharton duct drains the submandibular gland at the sublingual caruncle. Bartholin duct drains the sublingual gland, and Rivinus ducts are the minor sublingual ducts.

Question 18Oral and Maxillofacial Anatomy, Histology and Physiology

A patient reports loss of sensation over the chin and lower lip after a mandibular fracture. Which nerve is most likely injured?

  1. Mylohyoid nerve
  2. Mental nerve Correct answer.
  3. Infraorbital nerve
  4. Long buccal nerve

Explanation

The mental nerve exits the mental foramen and supplies sensation to the chin and lower lip, so it is commonly injured in fractures involving the mandibular body or parasymphysis. The infraorbital nerve supplies the midface, not the chin. The long buccal nerve supplies buccal gingiva, and the mylohyoid nerve is motor to the mylohyoid and anterior digastric.

Question 19Oral and Maxillofacial Anatomy, Histology and Physiology

Which primary tooth is typically the last to erupt in the maxillary arch?

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

Explanation

The primary maxillary second molar usually erupts last in the maxillary arch, at approximately 25 to 33 months of age. The primary central incisors erupt first at about 8 to 12 months. The maxillary lateral incisor and first molar erupt earlier than the second molar.

Question 20Oral and Maxillofacial Anatomy, Histology and Physiology

Which epithelial structure gives rise to the root sheath that induces cementum formation?

  1. Rests of Malassez
  2. Reduced enamel epithelium
  3. Hertwig epithelial root sheath Correct answer.
  4. Dental lamina

Explanation

Hertwig epithelial root sheath is a collar of epithelial cells that guides root development; its fragmentation exposes the root dentin and allows cementoblasts to deposit cementum. The dental lamina initiates tooth development, and reduced enamel epithelium covers the erupting crown. Rests of Malassez are remnants of the root sheath in the periodontal ligament.

Question 21Oral and Maxillofacial Anatomy, Histology and Physiology

A 30-year-old patient has a cusp of Carabelli. On which tooth surface is it typically located?

  1. Lingual surface of the mandibular second molar
  2. Occlusal surface of the maxillary second premolar
  3. Lingual surface of the maxillary first molar Correct answer.
  4. Buccal surface of the mandibular first molar

Explanation

The cusp of Carabelli is an accessory cusp located on the mesiolingual surface of the maxillary first permanent molar. It is most common in the maxillary first molar and rare in the mandibular teeth. Its presence is a useful anatomical variant in restorative and endodontic treatment planning.

Question 22Oral and Maxillofacial Anatomy, Histology and Physiology

Which of the following best explains why the mandibular first molar can be mistaken for a primary tooth?

  1. It erupts within an intact primary arch without exfoliating a predecessor Correct answer.
  2. It erupts after the premolars replace the primary molars
  3. It is always smaller than the primary second molar
  4. It has a crown with a distinct cervical constriction

Explanation

The mandibular first molar erupts distal to the primary second molar without replacing any primary tooth, so it appears in an otherwise intact primary arch around age 6. This positional eruption is why it is sometimes mistaken for a primary tooth. It is larger than the primary second molar and has a less pronounced cervical constriction than primary teeth.

Question 23Oral and Maxillofacial Anatomy, Histology and Physiology

Which feature distinguishes interglobular dentin from normal circumpulpal dentin?

  1. It contains a higher density of peritubular dentin
  2. It lacks dentinal tubules entirely
  3. It contains unmineralized globular spaces between mineralized globules Correct answer.
  4. It is formed only after pulp exposure

Explanation

Interglobular dentin results from incomplete fusion of mineralized globules, leaving unmineralized interglobular spaces between them, often near the mantle dentin. It still contains dentinal tubules and is not a reparative response to pulp exposure. It represents defective or incomplete mineralization rather than increased peritubular dentin.

Question 24Oral and Maxillofacial Anatomy, Histology and Physiology

Which anatomical structure must be identified to perform a safe inferior alveolar nerve block, where the needle is directed toward the mandibular foramen?

  1. Lingula of the mandible Correct answer.
  2. Mylohyoid line
  3. Coronoid process
  4. Genial tubercles

Explanation

The lingula of the mandible is a bony projection that overlies the mandibular foramen on the medial ramus, serving as a landmark for inferior alveolar nerve block. The coronoid process is anterior to the ramus, and the genial tubercles are on the lingual symphysis. The mylohyoid line is a ridge on the medial mandible but not the foramen landmark.

Question 25Oral Pathology and Oral Medicine

A 34-year-old woman presents with a 4 mm shallow, painful ulcer on the ventral tongue with a yellow fibrinous base and a red halo, preceded by a vesicle 2 days earlier. She has similar episodes 3–4 times yearly. What is the most likely diagnosis?

  1. Traumatic ulceration from a sharp cusp
  2. Squamous cell carcinoma
  3. Recurrent aphthous stomatitis (minor) Correct answer.
  4. Secondary herpes simplex infection

Explanation

Minor recurrent aphthous ulcers are shallow, under 1 cm, heal within 10–14 days without scarring, and recur periodically; they begin as an ulcer rather than a vesicle. Vesicle-precursor lesions that rupture into clustered erosions suggest herpes, but solitary recurrent shallow ulcers on non-keratinized mucosa fit aphthous disease.

Question 26Oral Pathology and Oral Medicine

Which mucosal site is most characteristically affected by oral lichen planus?

  1. Palatine tonsil
  2. Floor of mouth
  3. Buccal mucosa Correct answer.
  4. Dorsal tongue

Explanation

Oral lichen planus most often affects the buccal mucosa bilaterally, typically presenting as reticular white striae (Wickham striae). The buccal mucosa is the classic site because the disease favors areas where the epithelium is thin and subjected to mild trauma.

Question 27Oral Pathology and Oral Medicine

A patient reports a sudden onset of unilateral facial paralysis with inability to close the eye, loss of the nasolabial fold, and altered taste on the same side over 24 hours. Which diagnosis fits best?

  1. Trigeminal neuralgia
  2. Bell palsy Correct answer.
  3. Myasthenia gravis
  4. Cerebrovascular accident

Explanation

Bell palsy is an acute idiopathic peripheral facial nerve palsy causing unilateral weakness of the entire face, including the forehead, with possible taste disturbance and eye-closure difficulty. The acute, isolated, unilateral lower motor neuron pattern without other neurologic deficits is characteristic.

Question 28Oral Pathology and Oral Medicine

Which organism is most commonly implicated in acute necrotizing ulcerative gingivitis?

  1. Candida albicans
  2. Human papillomavirus type 16
  3. Streptococcus mutans
  4. Prevotella intermedia with fusiform bacteria and spirochetes Correct answer.

Explanation

Acute necrotizing ulcerative gingivitis is a fusospirochetal infection in which Prevotella intermedia, fusiform bacilli, and spirochetes act together, often in the setting of stress, smoking, or poor oral hygiene. The punched-out, crater-like interdental papillae with pseudomembrane reflect this mixed anaerobic flora.

Question 29Oral Pathology and Oral Medicine

A 45-year-old man has a painless, fluctuant swelling of the floor of the mouth that elevates the tongue and is translucent and bluish. Which diagnosis is most likely?

  1. Pleomorphic adenoma
  2. Ludwig angina
  3. Dermoid cyst
  4. Ranula Correct answer.

Explanation

A ranula is a mucocele arising from the sublingual gland that presents as a painless, bluish, fluctuant floor-of-mouth swelling displacing the tongue. Its translucent appearance and location over the sublingual gland are typical.

Question 30Oral Pathology and Oral Medicine

Which radiographic feature is most characteristic of an odontogenic keratocyst?

  1. Cotton-wool radiopacity
  2. Well-defined radiolucency that grows along the bone with minimal expansion Correct answer.
  3. Sunburst periosteal reaction
  4. Ground-glass bone texture

Explanation

Odontogenic keratocysts typically appear as well-defined radiolucencies that extend along the medullary cavity with little buccolingual expansion, especially in the posterior mandible. This growth pattern helps distinguish them from other cysts and tumors.

Question 31Oral Pathology and Oral Medicine

A patient develops a burning sensation and erythema on the palate after using a new denture for several days. Which factor most directly predisposes to denture stomatitis?

  1. Continuous denture wear with poor denture hygiene Correct answer.
  2. Increased salivary flow
  3. High-protein diet
  4. Bruxism

Explanation

Denture stomatitis is chiefly caused by Candida albicans proliferation beneath an ill-fitting or continuously worn denture, especially with poor hygiene and reduced salivary flow. Removing the denture at night and cleaning it reduces the fungal load.

Question 32Oral Pathology and Oral Medicine

A 60-year-old man has a persistent, indurated ulcer with rolled margins on the lateral border of the tongue for 6 weeks. He smokes and drinks alcohol daily. Which is the most appropriate immediate step?

  1. Prescribe topical corticosteroids and review in 4 weeks
  2. Reassure and advise mouth rinses
  3. Prescribe antibiotics for 7 days
  4. Refer for urgent biopsy and specialist assessment Correct answer.

Explanation

A persistent indurated ulcer with rolled margins in a high-risk patient is suspicious for oral squamous cell carcinoma and requires urgent biopsy and specialist referral. Delay with empirical treatment risks progression and worsens prognosis.

Question 33Oral Pathology and Oral Medicine

Which clinical finding best distinguishes a mucocele from a fibroma on the lower lip?

  1. Mucocele is fluctuant and bluish with a history of fluctuation in size Correct answer.
  2. Fibroma is painful and rapidly enlarging
  3. Mucocele is firm and pedunculated
  4. Fibroma is fluctuant and bluish

Explanation

A mucocele is a retention or extravasation cyst of a minor salivary gland that appears as a soft, fluctuant, bluish nodule that may wax and wane as it ruptures and refills. A fibroma is a firm, sessile, mucosa-colored reactive nodule from chronic trauma.

Question 34Oral Pathology and Oral Medicine

A patient with a history of recurrent herpes labialis reports a prodrome of tingling before vesicles appear. Which statement about the prodrome is correct?

  1. It reflects reactivation of latent virus in the trigeminal ganglion with migration along the nerve Correct answer.
  2. It reflects viral replication in the dorsal root ganglion
  3. It indicates a new primary infection
  4. It is caused by bacterial superinfection

Explanation

Recurrent herpes labialis results from reactivation of latent herpes simplex virus in the trigeminal ganglion, with virus traveling along sensory nerve branches to the lip. The tingling prodrome corresponds to this neural reactivation and migration before vesicle formation.

Question 35Oral Pathology and Oral Medicine

Which laboratory finding is most consistent with primary Sjögren syndrome?

  1. Elevated serum calcium
  2. Elevated serum amylase
  3. Positive anti-double-stranded DNA
  4. Positive anti-Ro/SSA and anti-La/SSB antibodies Correct answer.

Explanation

Primary Sjögren syndrome is characterized by sicca symptoms with autoantibodies against Ro/SSA and La/SSB, often with a positive labial salivary gland biopsy and reduced Schirmer test. These antibodies support the diagnosis of the autoimmune exocrinopathy.

Question 36Oral Pathology and Oral Medicine

A 28-year-old woman has multiple painful oral ulcers and a history of similar genital ulcers and uveitis. Which diagnosis should be considered?

  1. Pemphigus vulgaris
  2. Behçet disease Correct answer.
  3. Erythema multiforme
  4. Iron deficiency anemia

Explanation

Behçet disease is a systemic vasculitis with recurrent oral and genital aphthous ulcers and ocular inflammation such as uveitis. The combination of oral, genital, and ocular lesions is the classic triad.

Question 37Oral Pathology and Oral Medicine

Which feature most reliably differentiates pemphigus vulgaris from mucous membrane pemphigoid on clinical examination?

  1. Mucous membrane pemphigoid shows positive Nikolsky sign
  2. Mucous membrane pemphigoid affects only keratinized mucosa
  3. Pemphigus vulgaris shows intraepithelial blisters that rupture easily, leaving widespread erosions Correct answer.
  4. Pemphigus vulgaris shows subepithelial blisters that remain intact

Explanation

Pemphigus vulgaris is an intraepithelial (suprabasal) acantholytic disease, so blisters are fragile and rupture quickly, producing extensive erosions and a positive Nikolsky sign. Mucous membrane pemphigoid is subepithelial, so blisters are more tense and remain intact longer, with scarring of mucosa.

Question 38Oral Pathology and Oral Medicine

A patient with long-standing iron deficiency anemia develops a smooth, red, depapillated tongue and angular cheilitis. Which term best describes the tongue change?

  1. Hairy tongue
  2. Geographic tongue
  3. Atrophic glossitis Correct answer.
  4. Fissured tongue

Explanation

Atrophic glossitis is loss of filiform papillae producing a smooth, red, sore tongue, classically associated with iron, B12, or folate deficiency. Angular cheilitis frequently coexists in these nutritional deficiencies.

Question 39Oral Pathology and Oral Medicine

Which of the following is the most appropriate initial management for a patient with symptomatic oral lichen planus limited to reticular striae without erosions?

  1. Topical corticosteroid application
  2. No treatment, with monitoring and reassurance Correct answer.
  3. Systemic chemotherapy
  4. Surgical excision of all striae

Explanation

Asymptomatic reticular oral lichen planus generally requires no active treatment, only reassurance, avoidance of triggers, and periodic monitoring for malignant transformation. Topical corticosteroids are reserved for symptomatic or erosive disease.

Question 40Oral Pathology and Oral Medicine

A patient reports a burning mouth that is worse in the evening and is associated with dry mouth and a bitter metallic taste, with normal-appearing mucosa. Which factor most strongly suggests a psychogenic component?

  1. Symptoms fluctuating with stress and improving with distraction Correct answer.
  2. Associated oral ulceration
  3. Constant pain present on waking
  4. Marked weight loss

Explanation

Burning mouth syndrome with a psychogenic component often shows symptoms that vary with stress, improve with distraction, and occur with a clinically normal mucosa. Organic causes tend to produce constant symptoms and identifiable mucosal or systemic findings.

Question 41Oral Pathology and Oral Medicine

Which radiographic appearance is typical of fibrous dysplasia of the jaws?

  1. Well-circumscribed unilocular radiolucency around a crown
  2. Ground-glass opacification with blending into surrounding bone Correct answer.
  3. Sunburst periosteal spiculation
  4. Multiple punched-out radiolucencies

Explanation

Fibrous dysplasia produces a ground-glass or orange-peel radiopacity in which the lesional bone blends imperceptibly with adjacent bone. It is a developmental fibro-osseous lesion that expands bone and may cause facial asymmetry.

Question 42Oral Pathology and Oral Medicine

A patient on long-term bisphosphonate therapy develops exposed necrotic bone in the mandible after a tooth extraction. Which term best describes this condition?

  1. Medication-related osteonecrosis of the jaw Correct answer.
  2. Paget disease of bone
  3. Osteomyelitis of the maxilla
  4. Osteoradionecrosis

Explanation

Medication-related osteonecrosis of the jaw is defined by exposed bone persisting more than 8 weeks in a patient with current or prior antiresorptive or antiangiogenic therapy and no history of head and neck radiation. Extraction is a common trigger.

Question 43Oral Pathology and Oral Medicine

A 7-year-old child has a well-defined unilocular radiolucency surrounding the crown of an unerupted mandibular first molar. The tooth is displaced. What is the most likely diagnosis?

  1. Dentigerous cyst Correct answer.
  2. Odontoma
  3. Ameloblastoma
  4. Radicular cyst

Explanation

A dentigerous cyst encloses the crown of an unerupted tooth and attaches at the cementoenamel junction, commonly affecting impacted mandibular third molars or unerupted premolars. It is the most common developmental odontogenic cyst.

Question 44Oral Pathology and Oral Medicine

Which clinical feature most strongly suggests a malignant rather than a benign salivary gland swelling?

  1. Slow growth over many years
  2. Firm, fixed mass with facial nerve palsy Correct answer.
  3. Soft, compressible consistency
  4. Bilateral diffuse enlargement

Explanation

A firm, fixed salivary mass with facial nerve palsy raises strong suspicion of malignancy because benign tumors are usually mobile and do not invade the nerve. Rapid growth and pain also favor malignancy.

Question 45Oral Pathology and Oral Medicine

A patient with HIV has a white, wipeable plaque on the buccal mucosa and dorsal tongue. Which diagnosis is most likely?

  1. Oral hairy leukoplakia
  2. Lichen planus
  3. Leukoplakia
  4. Pseudomembranous candidiasis Correct answer.

Explanation

Pseudomembranous candidiasis appears as white curd-like plaques that wipe off to leave an erythematous base, and it is common in immunocompromised patients such as those with HIV. It responds to antifungal therapy.

Question 46Oral Pathology and Oral Medicine

Which statement about the malignant transformation potential of oral lichen planus is most accurate?

  1. It has no malignant potential
  2. Risk is highest in reticular lesions
  3. A small but real risk warrants long-term follow-up Correct answer.
  4. All cases progress to carcinoma within 5 years

Explanation

Oral lichen planus carries a small but recognized risk of malignant transformation to squamous cell carcinoma, so long-term periodic review is advised, particularly for erosive or atrophic lesions. The risk is low overall and not universal.

Question 47Oral Pathology and Oral Medicine

A 55-year-old with a 20-year history of iron deficiency anemia and dysphagia is found to have a postcricoid web and an oral mucosal lesion. Which syndrome should be suspected?

  1. Plummer-Vinson syndrome Correct answer.
  2. Sjögren syndrome
  3. Peutz-Jeghers syndrome
  4. Gardner syndrome

Explanation

Plummer-Vinson syndrome combines iron deficiency anemia, dysphagia from esophageal webs, and atrophic oral mucosal changes, and it is associated with an increased risk of upper aerodigestive carcinoma. The triad of anemia, dysphagia, and glossitis is characteristic.

Question 48Oral Pathology and Oral Medicine

A patient with a history of treated acromegaly presents with mandibular prognathism and spacing of teeth. Which mechanism best explains the oral changes?

  1. Excess growth hormone causing continued bone apposition and soft tissue enlargement Correct answer.
  2. Excess parathyroid hormone causing bone resorption
  3. Excess insulin causing gingival overgrowth
  4. Excess cortisol causing bone deposition

Explanation

Acromegaly results from excess growth hormone, usually from a pituitary adenoma, causing continued appositional growth of the mandible and enlargement of soft tissues, which produces prognathism, tooth spacing, and macroglossia. These changes are not caused by parathyroid, cortisol, or insulin excess.

Question 49Cariology and Restorative Dentistry

According to the classic acidogenic theory, which sequence best describes the initiation of a smooth-surface carious lesion?

  1. Mechanical abrasion removes surface enamel, allowing bacteria to invade the dentinal tubules directly
  2. Fluoride ions displace calcium in the hydroxyapatite lattice, weakening the crystal and causing collapse
  3. Fermentable carbohydrate is metabolised by plaque bacteria, producing organic acids that diffuse into enamel and demineralise it Correct answer.
  4. Salivary proteins precipitate on enamel and are then digested by proteolytic bacteria, exposing the dentine

Explanation

The acidogenic (chemoparasitic) theory holds that dietary fermentable carbohydrate is converted by plaque microorganisms into organic acids, chiefly lactic acid, which diffuse into enamel and dissolve mineral. This produces subsurface demineralisation with a relatively intact surface layer. Proteolysis and abrasion are separate mechanisms and do not describe caries initiation.

Question 50Cariology and Restorative Dentistry

Which bacterial species is most strongly associated with the initiation of coronal caries on a previously sound tooth surface?

  1. Streptococcus mutans Correct answer.
  2. Actinomyces israelii
  3. Veillonella parvula
  4. Lactobacillus acidophilus

Explanation

Streptococcus mutans is the organism most consistently linked to the initiation of coronal caries because of its acidogenicity, aciduricity and ability to adhere to the pellicle via glucosyltransferase-derived glucans. Lactobacilli are more associated with established cavitated lesions and progression. Actinomyces and Veillonella are not regarded as primary initiators of smooth-surface caries.