Diseases of the Oral Cavity and Salivary Glands — MCQs

Diseases of the Oral Cavity and Salivary Glands Indian Medical PG Practice Questions and MCQs

Question 271: What is the most common cyst of the oral region?

A. Dentigerous cyst
B. Keratocyst
C. Dermoid cyst
D. Periapical cyst (Correct Answer)

Explanation: **Explanation:** The **Periapical cyst** (also known as a **Radicular cyst**) is the most common cyst of the oral cavity, accounting for approximately 50–75% of all odontogenic cysts. It is an inflammatory cyst that arises from the epithelial rests of Malassez in the periodontal ligament. It typically develops at the apex of a non-vital (necrotic) tooth due to dental caries or trauma. **Analysis of Options:** * **A. Dentigerous cyst:** This is the second most common odontogenic cyst. It is a developmental cyst that forms around the crown of an **unerupted tooth** (most commonly the mandibular third molar). * **B. Keratocyst (Odontogenic Keratocyst/OKC):** Known for its aggressive behavior and high recurrence rate. While clinically significant due to its association with Gorlin-Goltz syndrome, it is less common than radicular or dentigerous cysts. * **C. Dermoid cyst:** A developmental cyst found in the midline of the floor of the mouth. It is relatively rare compared to odontogenic cysts. **High-Yield Clinical Pearls for NEET-PG:** * **Most common odontogenic cyst:** Periapical (Radicular) cyst. * **Most common developmental odontogenic cyst:** Dentigerous cyst. * **Radiological appearance:** Periapical cysts appear as a well-defined unilocular radiolucency at the apex of a pulp-involved tooth. * **Key Histology:** Characterized by **Rushton bodies** (eosinophilic linear/curved inclusions) in the epithelial lining. * **Treatment:** Endodontic (Root Canal) treatment or extraction with cyst enucleation.

Question 272: A 23-year-old female patient complains of decreased mouth opening for the past 4 days. What is the most likely cause?

A. Impacted third molar (Correct Answer)
B. Oral submucous fibrosis
C. Oropharyngeal fibrosis
D. Bony ankylosis of the temporomandibular joint

Explanation: **Explanation:** The correct answer is **Impacted third molar**. The key to solving this clinical scenario lies in the **acute onset** (4 days) of the symptoms. 1. **Why Impacted Third Molar is correct:** An impacted third molar (wisdom tooth) often leads to **Pericoronitis**—inflammation of the soft tissues surrounding the crown of a partially erupted tooth. This inflammation frequently spreads to the masseter muscle or the pterygomandibular space, causing **protective muscle spasm (Trismus)**. In a young adult (20–25 years), acute trismus is most commonly odontogenic in origin. 2. **Why the other options are incorrect:** * **Oral Submucous Fibrosis (OSMF):** While a very common cause of restricted mouth opening in India (due to betel nut chewing), it is a **chronic, progressive** condition. It does not develop over 4 days. * **Oropharyngeal Fibrosis:** This is typically a sequela of severe trauma, chemical burns, or radiotherapy. It is a chronic scarring process, not an acute presentation. * **Bony Ankylosis of the TMJ:** This results in permanent, severe restriction of jaw movement. It usually follows trauma or infection (like septic arthritis) and develops over **months to years**, not days. **High-Yield Clinical Pearls for NEET-PG:** * **Trismus vs. Ankylosis:** Trismus is a functional/spasmodic restriction (often reversible), whereas ankylosis is a structural/mechanical restriction. * **Most common cause of Trismus:** Impacted third molar/Pericoronitis. * **Quinsy (Peritonsillar Abscess):** Another high-yield cause of acute trismus due to irritation of the internal pterygoid muscle. * **OSMF Hallmark:** Presence of palpable vertical fibrous bands in the buccal mucosa and blanched appearance.

Question 273: What is the most common cause of unilateral parotid swelling in a 27-year-old male?

A. Warthin's tumor
B. Pleomorphic adenoma (Correct Answer)
C. Adenocarcinoma
D. Hemangioma

Explanation: **Explanation:** **Pleomorphic Adenoma (Benign Mixed Tumor)** is the most common salivary gland tumor overall, accounting for approximately 80% of all parotid tumors. It typically presents as a slow-growing, painless, firm, and mobile unilateral swelling. While it can occur at any age, it most frequently presents in the 3rd to 5th decades of life, making it the most likely diagnosis for a 27-year-old male with unilateral parotid enlargement. **Analysis of Incorrect Options:** * **Warthin’s Tumor (Papillary Cystadenoma Lymphomatosum):** This is the second most common benign parotid tumor. However, it typically affects older males (5th–6th decade), is strongly associated with smoking, and is the most common salivary tumor to present **bilaterally** (though often metachronous). * **Adenocarcinoma:** While malignant tumors can cause parotid swelling, they are less common than benign ones. Malignancy is usually suspected if there is rapid growth, pain, skin fixation, or facial nerve palsy. * **Hemangioma:** This is the most common salivary gland tumor in **children/infants**, not adults. It typically presents as a soft, bluish swelling that may enlarge with crying. **NEET-PG High-Yield Pearls:** * **Most common site for salivary tumors:** Parotid gland (80%). * **Most common benign tumor:** Pleomorphic Adenoma (most common in both adults and children). * **Most common malignant tumor (Overall):** Mucoepidermoid carcinoma. * **Most common malignant tumor (Submandibular/Minor glands):** Adenoid cystic carcinoma (known for perineural invasion). * **Frey’s Syndrome:** A common post-operative complication of parotidectomy (diagnosed by the Minor’s Starch-Iodine test).

Question 274: What is the investigation of choice for submandibular sialolithiasis?

A. Sialography
B. CT scan
C. USG
D. X-ray (Correct Answer)

Explanation: **Explanation:** **1. Why X-ray is the Correct Answer:** For submandibular sialolithiasis, the **Investigation of Choice (IOC)** is a plain X-ray. This is because approximately **80-90% of submandibular stones are radiopaque** due to their high calcium and phosphate content. The specific view used is the **Intraoral Periapical (IOPA) view** or the **Mandibular Occlusal view**, which effectively visualizes stones within the Wharton’s duct or the gland itself. **2. Analysis of Incorrect Options:** * **Sialography (A):** Historically used to visualize the ductal system using contrast. However, it is **contraindicated in acute infection** and can push the stone further back into the gland. It is rarely used now for diagnosis. * **CT Scan (B):** While highly sensitive for detecting small or multiple stones, it is expensive and involves radiation. It is usually reserved for complex cases or when X-rays are negative but clinical suspicion remains high. * **USG (C):** A non-invasive first-line screening tool that is excellent for detecting radiolucent stones, but X-ray remains the standard initial investigation of choice for the submandibular gland. **3. Clinical Pearls for NEET-PG:** * **Submandibular vs. Parotid:** 80% of submandibular stones are radiopaque, whereas 80% of parotid stones are **radiolucent** (making USG or CT better for parotid stones). * **Wharton’s Duct:** The most common site for sialolithiasis due to the alkaline nature of saliva, high calcium content, and the upward (antigravity) course of the duct. * **Clinical Presentation:** "Mealtime syndrome"—recurrent painful swelling of the gland triggered by the sight or smell of food. * **Gold Standard:** Non-contrast CT (NCCT) is the most sensitive imaging modality, but for exam purposes, X-ray is the established IOC for submandibular stones.

Question 275: Which type of caries is associated with pre-eruptive enamel hypoplasia?

A. Secondary caries
B. Chronic caries
C. Occult caries (Correct Answer)
D. Incipient caries

Explanation: **Explanation:** **Occult caries** (also known as "hidden caries") refers to carious lesions that are not clinically visible on the enamel surface during a routine visual examination but are detected radiographically in the underlying dentin. The association with **pre-eruptive enamel hypoplasia** is a key diagnostic feature. In this condition, a developmental defect or hypoplastic pit exists on the enamel surface before the tooth even erupts. Once the tooth enters the oral cavity, bacteria penetrate this microscopic defect. While the surface enamel appears relatively intact or minimally affected, the decay spreads rapidly and extensively within the softer dentin underneath. **Analysis of Incorrect Options:** * **Secondary caries:** Also called recurrent caries, these occur at the margins of an existing restoration (filling) due to microleakage. * **Chronic caries:** These are slow-progressing lesions, often characterized by a large, open cavity with hard, leathery, and darkly pigmented dentin. * **Incipient caries:** This is the earliest stage of enamel decay (white spot lesion) that has not yet penetrated the dentino-enamel junction (DEJ) and can often be remineralized. **High-Yield NEET-PG Pearls:** * **Diagnosis:** Occult caries are best diagnosed using **Bitewing radiographs**. * **Clinical Presentation:** A "fluoride syndrome" is sometimes associated with this, where fluoride makes the surface enamel very hard and resistant, masking the extensive destruction occurring in the dentin below. * **Pre-eruptive Intracoronal Resorption (PIR):** Often confused with occult caries, PIR is a radiolucent lesion found in the dentin of unerupted teeth, whereas occult caries occur only after the tooth is exposed to the oral environment.

Question 276: Which of the following is true about aphthous ulcers?

A. Viral predisposition (Correct Answer)
B. Recurrent ulcers
C. Deep ulcers
D. Involves the mucosa of the hard palate

Explanation: **Explanation:** Aphthous ulcers (Recurrent Aphthous Stomatitis) are common, painful, inflammatory oral mucosal lesions. **Why Option A is Correct:** While the exact etiology of aphthous ulcers is idiopathic, they are strongly associated with a **viral predisposition**, particularly the **Human Herpes Virus-6 (HHV-6)** and Cytomegalovirus. Other triggers include genetic factors, stress, trauma, and nutritional deficiencies (Vitamin B12, Iron, Folic acid). **Analysis of Incorrect Options:** * **Option B (Recurrent ulcers):** While the condition is indeed recurrent, in the context of standard NEET-PG questioning patterns and specific textbook references (like Dhingra), the "viral predisposition" is often highlighted as a key etiopathogenic factor. *Note: In many clinical contexts, B is also technically true, but A is the preferred academic answer regarding etiology.* * **Option C (Deep ulcers):** Most aphthous ulcers (Minor type, 80%) are **superficial**, small (<10mm), and non-scarring. Only the "Major" variant (Sutton’s disease) is deep and leaves a scar. * **Option D (Hard palate):** Aphthous ulcers characteristically involve **non-keratinized mucosa** (buccal mucosa, labial mucosa, floor of mouth). They typically **spare** the keratinized mucosa of the hard palate and gingiva (which are more commonly involved in Herpetic Gingivostomatitis). **High-Yield Clinical Pearls for NEET-PG:** * **Triad of Behçet’s Syndrome:** Recurrent oral aphthous ulcers, genital ulcers, and uveitis. * **Appearance:** Well-defined, round/oval ulcers with a **central yellowish-grey necrotic base** and a **peripheral erythematous halo**. * **Treatment:** Topical corticosteroids (Triamcinolone) and analgesics. For severe cases, systemic steroids or Thalidomide may be used.

Question 277: Pain due to acute irreversible pulpitis is:

A. Spontaneous (Correct Answer)
B. Sharp-shock like
C. Lasting for short duration
D. Continuous

Explanation: **Explanation:** **Acute Irreversible Pulpitis** is a clinical condition where the dental pulp is damaged beyond repair due to inflammation, typically resulting from deep caries or trauma. **1. Why "Spontaneous" is correct:** The hallmark of irreversible pulpitis is **spontaneous pain**. Unlike reversible pulpitis, where pain requires an external stimulus (like cold or sweets), the pain in the irreversible stage occurs without any provocation. This is due to increased intrapulpal pressure and the release of inflammatory mediators that lower the threshold of nociceptors, causing them to fire even in the absence of external triggers. **2. Why other options are incorrect:** * **Sharp-shock like:** This is characteristic of **Trigeminal Neuralgia**. The pain in pulpitis is typically described as dull, throbbing, or aching, though it can be severe. * **Lasting for short duration:** This describes **Reversible Pulpitis**. In reversible cases, pain subsides immediately (within seconds) after the stimulus is removed. In irreversible pulpitis, the pain lingers for minutes to hours. * **Continuous:** While the pain can be prolonged, it is classically described as **intermittent or spontaneous episodes** rather than a constant, never-ending state. Continuous pain is more often associated with periapical abscesses or advanced necrosis. **High-Yield Clinical Pearls for NEET-PG:** * **Night Pain:** A classic symptom of irreversible pulpitis is pain that worsens when the patient lies down (due to increased cephalic blood pressure). * **Referred Pain:** Pain is often poorly localized and may be referred to the ear (if mandibular molars are involved) or the temple. * **Treatment:** The only definitive treatments are **Root Canal Treatment (RCT)** or extraction. * **Progression:** If left untreated, irreversible pulpitis leads to **pulpal necrosis**, at which point the tooth may become asymptomatic until a periapical infection develops.

Question 278: Non-inflammatory, non-neoplastic enlargement of the salivary gland is:

A. Sialadenoma
B. Sialosis
C. Sialadenosis
D. Both Sialosis and Sialadenosis (Correct Answer)

Explanation: ### Explanation **Concept Overview** The correct answer is **D (Both Sialosis and Sialadenosis)** because these two terms are synonymous. They describe a benign, non-inflammatory, and non-neoplastic condition characterized by recurrent, painless, bilateral enlargement of the salivary glands, most commonly the **parotid gland**. **Why the Correct Answer is Right** * **Sialosis/Sialadenosis:** The pathophysiology involves a peripheral autonomic neuropathy leading to acinar hypertrophy (enlargement of cells) rather than an increase in cell number (hyperplasia) or inflammation. * It is typically associated with systemic metabolic or endocrine disorders, such as **Diabetes Mellitus**, chronic alcoholism, malnutrition (Bulimia/Anorexia), and liver cirrhosis. **Analysis of Other Options** * **A. Sialadenoma:** This refers to a true benign epithelial neoplasm (tumor) of the salivary gland (e.g., Pleomorphic adenoma). The question specifically excludes neoplastic conditions. * **B & C:** While both are technically correct, selecting only one would be incomplete as they are interchangeable medical terms for the same pathology. **High-Yield Clinical Pearls for NEET-PG** * **Clinical Presentation:** Look for a "soft, non-tender, bilateral parotid swelling" in a patient with a history of alcohol abuse or uncontrolled diabetes. * **Sialography Finding:** Often shows a **"leafless tree"** appearance due to the compression of small ducts by hypertrophied acini. * **Histology:** Characterized by enlarged acinar cells (up to 2-3 times normal size) with cytoplasm packed with zymogen granules, but **no inflammatory infiltrate**. * **Management:** Primarily involves treating the underlying systemic cause (e.g., glycemic control or nutritional rehabilitation).

Question 279: A patient presents with diffuse bilateral swelling below the chin region. Intraorally, the lower left molar is infected. What is the probable source of infection?

A. Submaxillary space infection
B. Submandibular space infection (Correct Answer)
C. Sublingual space infection
D. Submental space infection

Explanation: ### Explanation The patient presents with signs of **Ludwig’s Angina**, a rapidly spreading cellulitis of the submandibular space. The key to this question lies in the anatomical relationship between the mandibular molars and the **mylohyoid muscle**. **1. Why Submandibular Space is Correct:** The submandibular space is divided by the mylohyoid muscle into the sublingual space (above) and the submaxillary space (below). The roots of the **2nd and 3rd mandibular molars** extend below the mylohyoid line. Therefore, an infection originating from these teeth (as seen in this patient) penetrates the medial cortical plate of the mandible below the muscle attachment, leading directly to a **submandibular space infection**. This typically presents as a "woody" or "brawny" bilateral swelling below the chin. **2. Analysis of Incorrect Options:** * **Submaxillary space infection:** While the submaxillary space is a *component* of the submandibular space, the term "Submandibular space" is the standard clinical descriptor for the entire complex involved in Ludwig’s Angina (comprising submental, sublingual, and submaxillary compartments). * **Sublingual space infection:** This occurs when the infection originates from teeth whose roots lie *above* the mylohyoid line (e.g., incisors, canines, premolars, and sometimes the 1st molar). * **Submental space infection:** This involves the midline area between the anterior bellies of the digastric muscles, usually arising from mandibular incisors. **3. NEET-PG High-Yield Pearls:** * **Ludwig’s Angina:** A bilateral involvement of submandibular, sublingual, and submental spaces. It is a **cellulitis**, not an abscess. * **Most common cause:** Dental infection (80%), specifically the 2nd and 3rd molars. * **Clinical Sign:** "Double Tongue" appearance (elevation and protrusion of the tongue). * **Primary Danger:** Asphyxia due to laryngeal edema or posterior displacement of the tongue. * **Management:** Airway maintenance is the priority, followed by IV antibiotics and incision/drainage if necessary.

Question 280: A 30-year-old man presents with fever, malaise, halitosis, and oral lesions. Examination reveals lymphadenopathy and inflamed gingiva with ulcerations of the interdental papillae that bleed easily. What is he MOST likely suffering from?

A. Ludwig's angina
B. Vincent's angina (Correct Answer)
C. Oral thrush
D. Lemierre's disease

Explanation: **Explanation:** The clinical presentation of fever, halitosis, and specifically **ulceration of the interdental papillae** that bleed easily is pathognomonic for **Vincent’s Angina**, also known as Acute Necrotizing Ulcerative Gingivitis (ANUG) or "Trench Mouth." **1. Why Vincent’s Angina is correct:** It is a non-contagious infection caused by a symbiotic combination of **fusiform bacilli** and **spirochetes** (*Borrelia vincentii*). The hallmark is the "punched-out" crater-like ulcers on the interdental papillae, covered by a gray pseudomembrane. Patients typically present with a metallic taste, foul breath (halitosis), and significant pain. **2. Why the other options are incorrect:** * **Ludwig’s Angina:** This is a rapidly spreading cellulitis of the submandibular, sublingual, and submental spaces. It presents with "woody" hard swelling of the neck and floor of the mouth, often causing airway compromise, but not localized interdental papillary ulcers. * **Oral Thrush (Candidiasis):** Caused by *Candida albicans*, it presents as white, curd-like patches that can be scraped off to reveal an erythematous base. It is usually painless and lacks the necrotizing gingivitis seen here. * **Lemierre’s Disease:** This is a rare, life-threatening condition characterized by septic thrombophlebitis of the internal jugular vein, usually following an oropharyngeal infection (often *Fusobacterium necrophorum*). It presents with neck pain and pulmonary septic emboli rather than primary gingival ulceration. **High-Yield Clinical Pearls for NEET-PG:** * **Causative Organisms:** *Fusobacterium fusiforme* and *Borrelia vincentii*. * **Risk Factors:** Poor oral hygiene, stress (common in soldiers, hence "Trench Mouth"), and smoking. * **Management:** Treatment involves debridement, hydrogen peroxide mouthwashes, and antibiotics (Metronidazole is the drug of choice). * **Differential:** Do not confuse Vincent's Angina (gingivitis) with **Vincent's Stomatitis** (involvement of the entire oral mucosa).

Practice by Chapter

Stomatitis

Practice Questions

Oral Ulcers

Practice Questions

Oral Leukoplakia

Practice Questions

Oral Cancers

Practice Questions

Sialadenitis

Practice Questions

Sialolithiasis

Practice Questions

Salivary Gland Tumors

Practice Questions

Ranula

Practice Questions

Xerostomia

Practice Questions

Sjögren's Syndrome

Practice Questions

Oral Manifestations of Systemic Diseases

Practice Questions

Temporomandibular Joint Disorders

Practice Questions

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