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DHA Dentist Exam study materials
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DHA Dentist Exam practice questions

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Question 1General Medicine and Medical Emergencies Relevant to Dentistry

Which vital sign value in an adult is most consistent with a hypertensive emergency requiring immediate medical referral before dental treatment?

  1. 214/122 mmHg with headache and visual disturbance Correct answer.
  2. 138/88 mmHg
  3. 118/76 mmHg
  4. 152/94 mmHg

Explanation

Severely elevated blood pressure with signs of target-organ damage (headache, visual change, chest pain, neurologic deficit) defines a hypertensive emergency and warrants emergency medical evaluation rather than elective dental care. Isolated mild or moderate elevations without symptoms are managed by deferral and medical follow-up.

Question 2General Medicine and Medical Emergencies Relevant to Dentistry

A patient with a documented penicillin allergy develops diffuse urticaria, wheeze and hypotension minutes after an antibiotic dose in the dental office. What is the first-line drug and route?

  1. Intravenous hydrocortisone
  2. Intramuscular epinephrine Correct answer.
  3. Oral diphenhydramine
  4. Nebulized salbutamol

Explanation

Anaphylaxis is treated first with intramuscular epinephrine, which reverses bronchospasm and vasodilation and prevents further mediator release. Antihistamines, corticosteroids and bronchodilators are adjuncts only and do not substitute for epinephrine.

Question 3General Medicine and Medical Emergencies Relevant to Dentistry

Which finding best distinguishes vasovagal syncope from a hypoglycemic episode in a dental patient?

  1. A history of skipping breakfast
  2. A measured capillary glucose of 3.1 mmol/L
  3. Bradycardia with a prodrome of nausea and warmth Correct answer.
  4. Pallor and diaphoresis

Explanation

Vasovagal syncope classically produces bradycardia with a prodrome of warmth, nausea and lightheadedness due to increased vagal tone. Hypoglycemia typically causes tremor, tachycardia, confusion and sweating with a low measured glucose.

Question 4General Medicine and Medical Emergencies Relevant to Dentistry

A patient taking warfarin for atrial fibrillation needs a simple extraction. Which preoperative measure is most appropriate?

  1. Double the warfarin dose on the day of surgery
  2. Give fresh frozen plasma routinely before every extraction
  3. Check the INR and liaise with the prescriber, proceeding if within therapeutic range Correct answer.
  4. Stop warfarin 5 days before extraction without substitution

Explanation

Most simple dental extractions can be performed with a therapeutic INR (generally up to about 3.5) using local hemostatic measures, so the INR should be checked and the prescriber consulted. Warfarin should not be stopped abruptly because of thromboembolic risk.

Question 5General Medicine and Medical Emergencies Relevant to Dentistry

Which clinical feature most strongly suggests that chest pain in the dental chair is cardiac rather than musculoskeletal in origin?

  1. Pain radiating to the left arm and jaw with diaphoresis Correct answer.
  2. Pain localized to a single carious tooth
  3. Pain reproduced by palpation of the masseter
  4. Pain that resolves when the mouth is closed

Explanation

Cardiac ischemic pain typically radiates to the arm, neck or jaw and is accompanied by diaphoresis, dyspnea or nausea. Pain reproduced by palpation or related to jaw position points to a musculoskeletal cause.

Question 6General Medicine and Medical Emergencies Relevant to Dentistry

A patient becomes unresponsive, is not breathing normally, and has no palpable pulse. After calling for help and starting chest compressions, what is the correct compression rate and depth for an adult?

  1. 140–160 per minute at 8 cm depth
  2. 100–120 per minute at 5–6 cm depth Correct answer.
  3. 60–80 per minute at 2 cm depth
  4. 80–100 per minute at 3 cm depth

Explanation

High-quality adult CPR uses compressions at 100–120 per minute with a depth of about 5–6 cm, allowing full chest recoil. Rates or depths outside this range reduce cardiac output and increase injury.

Question 7General Medicine and Medical Emergencies Relevant to Dentistry

Which presentation is most characteristic of an acute adrenal (addisonian) crisis during a stressful dental procedure in a patient with known adrenal insufficiency?

  1. Hypotension with vomiting, weakness and confusion Correct answer.
  2. Fever with a productive cough
  3. Hypertension with bradycardia
  4. Sudden unilateral facial paralysis

Explanation

Adrenal crisis causes glucocorticoid deficiency with hypotension, nausea, vomiting, weakness and altered mental status, often triggered by stress or infection. Treatment requires urgent glucocorticoid replacement and fluid resuscitation.

Question 8General Medicine and Medical Emergencies Relevant to Dentistry

A patient with type 1 diabetes has a capillary glucose of 2.6 mmol/L and is conscious and able to swallow. What is the most appropriate immediate management?

  1. Give a dose of long-acting insulin
  2. Give 15–20 g of fast-acting oral carbohydrate and recheck in 15 minutes Correct answer.
  3. Administer intramuscular glucagon
  4. Recline the patient and monitor without intervention

Explanation

Conscious hypoglycemia is treated with rapidly absorbed oral carbohydrate (about 15–20 g), followed by rechecking glucose after 15 minutes and repeating if still low. Glucagon or intravenous dextrose is reserved for patients who cannot swallow or are unconscious.

Question 9General Medicine and Medical Emergencies Relevant to Dentistry

Which medication history most increases the risk of a hypertensive crisis during a dental appointment?

  1. A beta-blocker taken that morning
  2. A proton pump inhibitor
  3. A monoamine oxidase inhibitor combined with a sympathomimetic vasoconstrictor Correct answer.
  4. An inhaled corticosteroid

Explanation

MAO inhibitors can potentiate sympathomimetic amines such as those in vasoconstrictor-containing local anesthetic solutions, precipitating a hypertensive crisis. Vasoconstrictor use should be minimized or avoided in such patients.

Question 10General Medicine and Medical Emergencies Relevant to Dentistry

A patient reports a history of angina and takes sublingual nitroglycerin. During treatment he develops crushing chest pain. Which action sequence is most appropriate?

  1. Place the patient supine and give a vasoconstrictor-containing local anesthetic
  2. Continue treatment and reassess at the end of the appointment
  3. Give aspirin 300 mg and discharge the patient home
  4. Stop treatment, sit the patient upright, give sublingual nitroglycerin as prescribed, and call emergency services if pain persists Correct answer.

Explanation

Suspected acute coronary syndrome requires stopping the procedure, positioning the patient comfortably, administering prescribed nitroglycerin, and activating emergency services if pain does not resolve promptly. This minimizes myocardial oxygen demand and shortens time to definitive care.

Question 11General Medicine and Medical Emergencies Relevant to Dentistry

Which finding in a patient's history most raises concern for infective endocarditis prophylaxis before an invasive dental procedure?

  1. A coronary artery stent placed 3 years ago
  2. Mitral valve prolapse without regurgitation
  3. A prosthetic heart valve Correct answer.
  4. Hypertension controlled with medication

Explanation

Prosthetic heart valves carry the highest risk of adverse outcomes from infective endocarditis, and prophylaxis is recommended for invasive dental procedures in such patients. Most other cardiac conditions, including uncomplicated mitral valve prolapse and coronary stents, do not warrant prophylaxis.

Question 12General Medicine and Medical Emergencies Relevant to Dentistry

Which clinical sign is most consistent with a transient ischemic attack rather than a vasovagal episode?

  1. Bilateral blurring of vision with sweating and pallor
  2. Unilateral weakness of the arm and slurred speech resolving within an hour Correct answer.
  3. Brief loss of consciousness after prolonged standing
  4. Nausea relieved by lying flat

Explanation

Focal neurologic deficits such as unilateral weakness or speech disturbance suggest cerebral ischemia and require urgent evaluation. Vasovagal events cause global symptoms like pallor, sweating and brief syncope without focal deficits.

Question 13General Medicine and Medical Emergencies Relevant to Dentistry

A patient with severe asthma reports daily wheeze and uses a reliever inhaler frequently. Which precaution is most important before elective dental treatment?

  1. Use only general anesthesia
  2. Avoid all local anesthetics
  3. Give a prophylactic antibiotic
  4. Ensure the patient has their reliever inhaler available and consider deferring if acutely wheezy Correct answer.

Explanation

Patients with poorly controlled asthma are at risk of acute bronchospasm; treatment should be deferred if they are acutely symptomatic, and their reliever inhaler must be accessible. Aspirin-containing analgesics and some triggers should be avoided in sensitive patients.

Question 14General Medicine and Medical Emergencies Relevant to Dentistry

Which statement about epinephrine in local anesthetic solutions for patients with cardiovascular disease is most accurate?

  1. Epinephrine should be given intravenously for hemostasis
  2. Epinephrine raises the seizure threshold
  3. Epinephrine is absolutely contraindicated in all cardiac patients
  4. Limited doses of epinephrine with careful aspiration are generally acceptable in stable cardiac patients Correct answer.

Explanation

Small, carefully administered doses of vasoconstrictor with aspiration are generally safe in stable cardiovascular disease and improve hemostasis and anesthesia quality. Absolute avoidance is not required, but dose limits and monitoring apply.

Question 15General Medicine and Medical Emergencies Relevant to Dentistry

A patient on long-term high-dose corticosteroid therapy undergoes a stressful surgical extraction. Why is supplemental corticosteroid considered?

  1. To prevent infective endocarditis
  2. To prevent hypertensive crisis
  3. To cover possible secondary adrenal insufficiency under stress Correct answer.
  4. To reverse the effects of local anesthetic

Explanation

Long-term exogenous steroids can suppress the hypothalamic-pituitary-adrenal axis, so an acute stressor may precipitate adrenal insufficiency. Supplemental glucocorticoid cover is considered for significant surgical stress.

Question 16General Medicine and Medical Emergencies Relevant to Dentistry

Which finding most suggests that a patient's dizziness is due to orthostatic hypotension rather than a cardiac arrhythmia?

  1. Symptoms occurring on standing that improve on sitting, with a fall in systolic pressure of 20 mmHg Correct answer.
  2. Palpitations with a documented irregular pulse
  3. Chest pain preceding the dizziness
  4. A family history of sudden cardiac death

Explanation

Orthostatic hypotension produces symptoms on standing with a documented postural drop in blood pressure and relief on sitting or lying down. Palpitations, chest pain and a family history of sudden death point toward a cardiac arrhythmia.

Question 17General Medicine and Medical Emergencies Relevant to Dentistry

Which action is most appropriate when a patient with a known seizure disorder begins to have a generalized tonic-clonic seizure during treatment?

  1. Clear the area, protect the head, and allow the seizure to run its course while timing it Correct answer.
  2. Give oral water immediately
  3. Restrain the limbs firmly
  4. Place objects between the teeth

Explanation

During a seizure the priority is to prevent injury by clearing the area and protecting the head while timing the event. Nothing should be placed in the mouth, and the patient should not be restrained; prolonged seizures require emergency services.

Question 18General Medicine and Medical Emergencies Relevant to Dentistry

A patient reports a history of peptic ulcer disease and is prescribed a nonsteroidal anti-inflammatory drug after extraction. Which precaution is most appropriate?

  1. Advise taking it on an empty stomach
  2. Combine with high-dose aspirin
  3. Prescribe the maximum dose for the longest duration
  4. Co-prescribe a gastroprotective agent or choose a paracetamol-based regimen Correct answer.

Explanation

NSAIDs increase the risk of ulcer bleeding, so in patients with ulcer history a gastroprotective agent or an alternative analgesic such as paracetamol is preferred. The lowest effective dose for the shortest time should be used.

Question 19General Medicine and Medical Emergencies Relevant to Dentistry

Which electrolyte disturbance is most likely to cause prolonged bleeding and should be considered in a patient with liver disease undergoing extraction?

  1. Hypercalcemia
  2. Hypernatremia
  3. Hyperkalemia
  4. Coagulopathy from impaired hepatic synthesis of clotting factors Correct answer.

Explanation

The liver synthesizes most clotting factors, so hepatic dysfunction can cause coagulopathy with prolonged bleeding. Checking platelet count and coagulation studies and using local hemostatic measures is important.

Question 20General Medicine and Medical Emergencies Relevant to Dentistry

A patient with chronic kidney disease on hemodialysis is scheduled for extraction. Which timing consideration is most appropriate?

  1. Avoid all local anesthesia
  2. Perform treatment without checking medications
  3. Schedule on the day after dialysis and review anticoagulation used during dialysis Correct answer.
  4. Schedule immediately before dialysis to reduce bleeding

Explanation

Patients on hemodialysis often receive heparin during sessions, so dental treatment is best scheduled the day after dialysis when hemostasis is more predictable. Medication review, including anticoagulants and renally cleared drugs, is also essential.

Question 21Oral Medicine, Oral Pathology, and Oral Diagnosis

Which organism is most commonly implicated as the primary pathogen in necrotizing ulcerative gingivitis (trench mouth)?

  1. Streptococcus mutans
  2. Prevotella intermedia with fusiform bacteria and spirochetes Correct answer.
  3. Candida albicans
  4. Actinomyces israelii

Explanation

Necrotizing ulcerative gingivitis is a polymicrobial anaerobic infection in which Prevotella intermedia, fusiform bacilli, and spirochetes act together. These organisms proliferate in the setting of stress, poor oral hygiene, and impaired host resistance.

Question 22Oral Medicine, Oral Pathology, and Oral Diagnosis

A patient reports a sudden, sharp, electric shock-like pain on the right cheek triggered by touching the skin or brushing teeth, lasting seconds. Which diagnosis is most likely?

  1. Postherpetic neuralgia
  2. Trigeminal neuralgia Correct answer.
  3. Atypical odontalgia
  4. Temporomandibular disorder

Explanation

Brief, lancinating, electric shock-like pain triggered by innocuous stimuli in the distribution of the trigeminal nerve is the classic presentation of trigeminal neuralgia. Attacks are paroxysmal and last seconds to a couple of minutes.

Question 23Oral Medicine, Oral Pathology, and Oral Diagnosis

Which clinical feature best distinguishes a recurrent aphthous ulcer from a traumatic ulcer?

  1. Presence of a pseudomembrane
  2. A single lesion with an indurated border
  3. A history of similar recurrent lesions on non-keratinized mucosa Correct answer.
  4. Location on the lateral border of the tongue

Explanation

Recurrent aphthous stomatitis is characterized by repeated episodes of ulcers typically on non-keratinized mucosa such as the buccal and labial mucosa. Traumatic ulcers are single and resolve once the cause is removed.

Question 24Oral Medicine, Oral Pathology, and Oral Diagnosis

Which of the following is the most common odontogenic cyst of the jaws?

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

Explanation

The radicular (periapical) cyst is the most frequent odontogenic cyst and arises from epithelial rests of Malassez after pulp necrosis. It presents at the apex of a non-vital tooth.

Question 25Oral Medicine, Oral Pathology, and Oral Diagnosis

Which condition is characterized by white, adherent plaques on the oral mucosa that cannot be wiped off and cannot be classified clinically as any other disease?

  1. Linea alba
  2. Oral candidiasis
  3. Lichen planus
  4. Leukoplakia Correct answer.

Explanation

Leukoplakia is a clinical diagnosis of exclusion: a predominantly white plaque that cannot be rubbed off and does not fit another definable lesion. Biopsy is required to rule out dysplasia or carcinoma.

Question 26Oral Medicine, Oral Pathology, and Oral Diagnosis

Which of the following is the most important risk factor for oral squamous cell carcinoma?

  1. Tobacco use Correct answer.
  2. Fluoride exposure
  3. Chronic candidiasis
  4. Bruxism

Explanation

Tobacco use, alone and especially in combination with alcohol, is the strongest established risk factor for oral squamous cell carcinoma. Risk rises with the dose and duration of exposure.

Question 27Oral Medicine, Oral Pathology, and Oral Diagnosis

A patient has unilateral facial paralysis with inability to close the eye, loss of the nasolabial fold, and a metallic taste disturbance. Which diagnosis is most consistent?

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

Explanation

Acute unilateral lower motor neuron facial palsy with inability to close the eye and associated taste disturbance is typical of Bell palsy. The forehead is involved because the lesion is peripheral to the facial nucleus.

Question 28Oral Medicine, Oral Pathology, and Oral Diagnosis

Which radiographic feature is most characteristic of a dentigerous cyst?

  1. A well-defined radiolucency attached at the cementoenamel junction of an unerupted tooth Correct answer.
  2. A ground-glass opacity of the maxilla
  3. A periapical radiolucency of a non-vital tooth
  4. A multilocular soap-bubble radiolucency in the posterior mandible

Explanation

A dentigerous cyst encloses the crown of an unerupted tooth and attaches at the cementoenamel junction. This distinguishes it from other pericoronal radiolucencies.

Question 29Oral Medicine, Oral Pathology, and Oral Diagnosis

Which of the following medications is most strongly associated with gingival overgrowth?

  1. Phenytoin Correct answer.
  2. Metformin
  3. Levothyroxine
  4. Atorvastatin

Explanation

Phenytoin, along with cyclosporine and calcium channel blockers, is a well-recognized cause of drug-induced gingival overgrowth. The enlargement is more pronounced in the presence of plaque.

Question 30Oral Medicine, Oral Pathology, and Oral Diagnosis

A patient presents with multiple painful vesicles and ulcers on the gingiva and hard palate, with fever and cervical lymphadenopathy. Which diagnosis is most likely?

  1. Herpangina
  2. Recurrent herpes labialis
  3. Primary herpetic gingivostomatitis Correct answer.
  4. Aphthous stomatitis

Explanation

Primary herpes simplex infection produces widespread vesicles and erosions on keratinized mucosa such as gingiva and hard palate, with systemic symptoms. It typically affects children or young adults.

Question 31Oral Medicine, Oral Pathology, and Oral Diagnosis

Which of the following best describes the classic clinical appearance of oral lichen planus?

  1. A painless fluctuant swelling of the lip
  2. A single indurated ulcer on the lateral tongue
  3. Yellowish nodules on the buccal mucosa
  4. Bilateral white reticular striae on the buccal mucosa Correct answer.

Explanation

Oral lichen planus most commonly presents as bilateral, symmetrical white reticular striae (Wickham striae) on the buccal mucosa. It is a chronic immune-mediated condition.

Question 32Oral Medicine, Oral Pathology, and Oral Diagnosis

Which laboratory finding is characteristic of pernicious anemia, which can present with glossitis and oral burning?

  1. Thrombocytosis with normal hemoglobin
  2. Elevated serum folate with normal B12
  3. Microcytic anemia with low ferritin
  4. Macrocytic anemia with low serum vitamin B12 Correct answer.

Explanation

Pernicious anemia results from intrinsic factor deficiency and produces a macrocytic anemia with low vitamin B12. Patients may develop atrophic glossitis and oral burning.

Question 33Oral Medicine, Oral Pathology, and Oral Diagnosis

Which of the following is the most appropriate initial management for a patient with a suspected oral mucocele on the lower lip?

  1. Observation and, if persistent, surgical excision Correct answer.
  2. Immediate radical excision with margins
  3. Systemic antifungal therapy
  4. Topical corticosteroid application

Explanation

Mucoceles are benign salivary extravasation phenomena that may resolve spontaneously, so observation is reasonable before conservative surgical removal. Recurrence is reduced by removing the associated minor salivary gland.

Question 34Oral Medicine, Oral Pathology, and Oral Diagnosis

Which finding on a panoramic radiograph is most suggestive of an ameloblastoma?

  1. A radiopaque mass attached to a tooth root
  2. A unilocular radiolucency at the apex of a carious tooth
  3. A diffuse ground-glass opacity
  4. A multilocular radiolucency with a soap-bubble appearance in the posterior mandible Correct answer.

Explanation

Ameloblastoma classically appears as a multilocular, soap-bubble or honeycomb radiolucency in the posterior mandible. It is locally aggressive and has a high recurrence rate.

Question 35Oral Medicine, Oral Pathology, and Oral Diagnosis

A patient with long-standing gastroesophageal reflux reports erosion of the palatal surfaces of the maxillary teeth. Which factor best explains this pattern?

  1. Attrition from nocturnal bruxism
  2. Erosion caused by dietary citrus fruits alone
  3. Abrasion from aggressive toothbrushing
  4. Regurgitated gastric acid pooling on the palatal surfaces Correct answer.

Explanation

In gastroesophageal reflux, regurgitated gastric acid contacts the palatal surfaces of the maxillary teeth, producing characteristic erosion there. The mandibular teeth are relatively spared because the tongue protects them.

Question 36Oral Medicine, Oral Pathology, and Oral Diagnosis

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

  1. Gingiva of the maxilla
  2. Lateral border of the tongue Correct answer.
  3. Hard palate
  4. Buccal mucosa

Explanation

The lateral border and ventral surface of the tongue are the most frequent intraoral sites for squamous cell carcinoma. These areas are bathed in saliva and exposed to carcinogens.

Question 37Oral Medicine, Oral Pathology, and Oral Diagnosis

A patient reports a burning sensation of the tongue and buccal mucosa that is present on waking and persists all day, with a normal clinical examination. Which diagnosis should be considered?

  1. Trigeminal neuralgia
  2. Burning mouth syndrome Correct answer.
  3. Recurrent aphthous stomatitis
  4. Oral submucous fibrosis

Explanation

Burning mouth syndrome is characterized by a chronic intraoral burning sensation with a clinically normal mucosa, often worst in the morning or throughout the day. Secondary causes such as anemia, diabetes, and dry mouth should be excluded.

Question 38Oral Medicine, Oral Pathology, and Oral Diagnosis

Which of the following is the most appropriate first step in evaluating a persistent oral ulcer that has not healed after removal of an apparent local irritant?

  1. Perform a panoramic radiograph only
  2. Prescribe a topical antifungal and review in 6 months
  3. Incisional biopsy of the lesion Correct answer.
  4. Reassure the patient and review in 1 year

Explanation

Any oral ulcer persisting beyond about two weeks after removal of local causes warrants biopsy to exclude malignancy. Incisional biopsy of the representative area is standard.

Question 39Oral Medicine, Oral Pathology, and Oral Diagnosis

Which of the following is a characteristic feature of oral submucous fibrosis?

  1. Painless bleeding on probing
  2. Progressive restricted mouth opening with mucosal blanching Correct answer.
  3. Fetor oris with necrotic papillae
  4. Diffuse gingival enlargement

Explanation

Oral submucous fibrosis results from areca (betel) nut chewing and causes juxtaepithelial fibrosis with progressive trismus and pale, blanched mucosa. It carries a significant risk of malignant transformation.

Question 40Oral Medicine, Oral Pathology, and Oral Diagnosis

A patient on warfarin requires a dental extraction with an INR of 3.8. Which is the most appropriate action?

  1. Consult the prescribing physician before proceeding with the extraction Correct answer.
  2. Stop warfarin permanently and extract the tooth
  3. Proceed immediately without any modification
  4. Double the warfarin dose before the procedure

Explanation

An INR of 3.8 exceeds the usual threshold for routine minor oral surgery, so the anticoagulation status should be discussed with the managing physician before extraction. Local hemostatic measures may be used once the INR is acceptable.

Question 41Oral Medicine, Oral Pathology, and Oral Diagnosis

Which of the following best explains why a radicular cyst is associated with a non-vital tooth?

  1. Odontogenic epithelium undergoes neoplastic transformation
  2. Salivary gland tissue undergoes cystic degeneration
  3. The reduced enamel epithelium surrounds an unerupted crown
  4. Epithelial rests of Malassez proliferate in response to periapical inflammation Correct answer.

Explanation

Pulp necrosis leads to periapical inflammation, which stimulates proliferation of epithelial rests of Malassez and cyst formation. This explains the consistent association of radicular cysts with non-vital teeth.

Question 42Oral Medicine, Oral Pathology, and Oral Diagnosis

A patient with a history of treated breast cancer presents with a well-circumscribed radiolucency in the posterior mandible. Which finding would most increase suspicion of a metastatic lesion rather than a primary odontogenic lesion?

  1. A positive pulp vitality test in adjacent teeth
  2. A soap-bubble multilocular pattern
  3. Presence of an impacted third molar within the radiolucency
  4. A history of malignancy with multiple lesions and rapid growth Correct answer.

Explanation

Metastatic jaw lesions are suggested by a known primary malignancy, rapid growth, and sometimes multiple lesions, often with a moth-eaten border. Metastases to the jaws most often affect the posterior mandible.

Question 43Oral Medicine, Oral Pathology, and Oral Diagnosis

Which of the following mechanisms best explains the oral manifestations of pemphigus vulgaris?

  1. Defective collagen synthesis in the lamina propria
  2. Autoantibodies against hemidesmosomes cause subepithelial separation
  3. IgE-mediated mast cell degranulation
  4. Autoantibodies against desmoglein cause intraepithelial acantholysis Correct answer.

Explanation

Pemphigus vulgaris is caused by IgG autoantibodies against desmoglein 1 and 3, producing intraepithelial acantholysis and fragile bullae that rupture into painful erosions.

Question 44Oral Medicine, Oral Pathology, and Oral Diagnosis

A patient with a suspected odontogenic infection has trismus, dysphagia, and elevation of the floor of the mouth. Which space infection is most likely, and why is it urgent?

  1. Chronic periodontitis, because it causes bone loss
  2. Periapical abscess, because it is confined to bone
  3. Ludwig angina, because it can compromise the airway Correct answer.
  4. Pericoronitis, because it causes localized pain

Explanation

Bilateral submandibular and sublingual space involvement with floor-of-mouth elevation and dysphagia characterizes Ludwig angina, a rapidly spreading cellulitis that threatens the airway. Urgent airway assessment and drainage are required.

Question 45Restorative Dentistry and Endodontics

Which dental material is most commonly used as a direct esthetic restoration for anterior teeth because it bonds micromechanically to etched enamel?

  1. Amalgam
  2. Zinc phosphate cement
  3. Glass ionomer cement
  4. Composite resin Correct answer.

Explanation

Composite resin bonds to acid-etched enamel via micromechanical interlocking and is widely used for direct anterior esthetics. Amalgam is non-esthetic and does not bond, while cements are luting agents.

Question 46Restorative Dentistry and Endodontics

In root canal treatment, the working length is best defined as the distance from a coronal reference point to which anatomic landmark?

  1. The apical constriction Correct answer.
  2. The cementoenamel junction
  3. The furcation
  4. The radiographic apex of the root

Explanation

Working length is measured to the apical constriction, generally 0.5-1.0 mm short of the radiographic apex, because instrumentation beyond it risks extrusion and damage.

Question 47Restorative Dentistry and Endodontics

What is the primary function of a rubber dam during endodontic treatment?

  1. To improve access to the pulp chamber
  2. To reduce the need for local anesthesia
  3. To isolate the tooth and maintain an aseptic field Correct answer.
  4. To shorten the setting time of sealer

Explanation

The rubber dam isolates the operative field, protects the airway, and helps maintain asepsis. It does not affect anesthesia requirements or sealer chemistry.

Question 48Restorative Dentistry and Endodontics

Which irrigant is the standard antimicrobial solution used during chemomechanical preparation of the root canal system?

  1. Hydrogen peroxide
  2. Sodium hypochlorite Correct answer.
  3. Chlorhexidine gluconate
  4. Saline

Explanation

Sodium hypochlorite is the primary irrigant because it dissolves organic tissue and is antimicrobial. Chlorhexidine lacks tissue-dissolving capacity and saline has no antimicrobial action.

Question 49Restorative Dentistry and Endodontics

Which bur type is designed with a non-cutting tip for safe axial extension during cavity preparation?

  1. Plain fissure bur Correct answer.
  2. Inverted cone bur
  3. Round bur
  4. Fissure crosscut bur

Explanation

A plain (non-crosscut) fissure bur has a safe, non-cutting tip that allows axial wall extension without gouging the pulpal floor. Crosscut fissure burs cut aggressively in all directions.

Question 50Restorative Dentistry and Endodontics

Which of the following is a characteristic of a Class II cavity preparation according to GV Black's classification?

  1. Involves the proximal surfaces of posterior teeth Correct answer.
  2. Involves only the occlusal pits and fissures
  3. Involves the cervical third of any tooth
  4. Involves the incisal angle of anterior teeth

Explanation

Class II preparations involve proximal surfaces of posterior teeth (premolars and molars). Class I is pits and fissures, Class IV involves the incisal angle, and Class V is the cervical third.