Diseases of the Oral Cavity and Salivary Glands Practice Questions

Q: Which of the following is not always a true odontogenic infection?

Maxillary sinusitis. **Explanation:** The core concept here is the distinction between infections that **originate** from the teeth (odontogenic) and those that can have multiple etiologies. **Why Maxillary Sinusitis is the correct answer:** While maxillary sinusitis can be odontogenic in origin (approximately 10–12% of cases, usually due to periapical infections of the maxillary molars or premolars), it is **not always** odontogenic. The vast majority of maxillary sinusitis cases are **rhinogenic**, following viral upper respiratory tract infections or allergic rhinitis. Therefore, it is the only option that is not inherently or "always" a true odontogenic infection. **Analysis of incorrect options:** * **Periapical Abscess:** This is a true odontogenic infection. It occurs at the apex of the tooth root, typically following dental caries that lead to pulp necrosis and subsequent infection of the periapical tissues. * **Periodontal Abscess:** This is also a true odontogenic infection. It originates in the supporting structures of the teeth (the periodontium), often due to deep periodontal pockets or food impaction. **High-Yield Clinical Pearls for NEET-PG:** * **Odontogenic Sinusitis:** Suspect this if the sinusitis is **unilateral** and associated with a **foul-smelling (cacosmia)** discharge. * **First Molar Rule:** The maxillary first molar is the tooth most commonly associated with odontogenic maxillary sinusitis due to the proximity of its roots to the sinus floor. * **Ludwig’s Angina:** A life-threatening cellulitis of the submandibular space, most commonly caused by an odontogenic infection of the **2nd and 3rd mandibular molars**.

Q: In MPDS (Masticatory Muscle Pain Dysfunction Syndrome), which muscle is most commonly involved?

Lateral pterygoid. **Explanation:** **Masticatory Muscle Pain Dysfunction Syndrome (MPDS)**, also known as Temporomandibular Joint Dysfunction Syndrome, is a psychophysiological disorder characterized by pain, muscle tenderness, and restricted jaw movement. **Why Lateral Pterygoid is the Correct Answer:** The **lateral pterygoid** is the most frequently involved muscle in MPDS. This is primarily due to its unique anatomical role: it is the only muscle of mastication responsible for **opening the mouth** (depression of the mandible) and protrusion. In cases of stress-induced bruxism or malocclusion, this muscle undergoes constant fatigue and spasm. Spasm of the lateral pterygoid leads to the characteristic "clicking" sound of the TMJ and trismus (limited mouth opening). **Analysis of Incorrect Options:** * **Masseter:** While the masseter is a powerful elevator of the jaw and often shows tenderness in chronic cases, it is typically involved secondary to the lateral pterygoid. * **Temporalis:** This muscle is often associated with "tension-type headaches" in MPDS patients, but it is not the primary or most common site of initial muscle dysfunction. * **Medial Pterygoid:** Like the masseter, this is an elevator muscle. While it can be involved in internal derangements, it is less frequently the primary source of pain compared to its lateral counterpart. **High-Yield Clinical Pearls for NEET-PG:** * **Classic Triad of MPDS:** Pain, clicking/popping sounds in the TMJ, and limitation of jaw movement. * **Etiology:** Often linked to psychological stress, anxiety, and parafunctional habits (bruxism). * **Management:** Conservative treatment is the first line, including reassurance, soft diet, NSAIDs, and muscle relaxants. Occlusal splints (night guards) are highly effective. * **Differential Diagnosis:** Must be distinguished from Costen’s Syndrome (an older term for TMJ neuralgia).

Q: Adenomatoid odontogenic tumour is most commonly found in which location?

Anterior maxilla. **Explanation:** Adenomatoid Odontogenic Tumour (AOT) is a benign, slow-growing epithelial odontogenic lesion. It is often referred to as the **"Two-Thirds Tumor"** because approximately 2/3rd of cases occur in the maxilla, 2/3rd occur in young females (teenagers), and 2/3rd are associated with an impacted tooth (most commonly the maxillary canine). **1. Why Anterior Maxilla is Correct:** The most frequent site for AOT is the **anterior maxilla** (incisor-canine region). It typically presents as a well-circumscribed radiolucency surrounding the crown and part of the root of an unerupted tooth, mimicking a dentigerous cyst. However, unlike a dentigerous cyst, AOT often extends apically beyond the cemento-enamel junction. **2. Analysis of Incorrect Options:** * **Anterior mandible:** While AOT can occur here, it is significantly less common than the maxillary site. * **Posterior maxilla:** AOT has a strong predilection for the anterior segments of the jaws; posterior involvement is rare. * **Ramus of mandible:** This is a classic site for **Ameloblastoma** or **Odontogenic Keratocyst (OKC)**, but not for AOT. **3. Clinical Pearls for NEET-PG:** * **Radiological Appearance:** Often shows "snowflake" or "driven-snow" calcifications within the radiolucency (intralesional radiopacities). * **Histopathology:** Characterized by duct-like structures lined by cuboidal or columnar epithelium and whorled masses of epithelial cells (Rosette pattern). * **Treatment:** Conservative surgical enucleation; recurrence is extremely rare. * **Key Association:** Always remember the association with the **impacted maxillary canine**.

Q: A 60-year-old man presents with an ulcer on the lateral margin of his tongue, also complaining of ear pain. What is the most probable diagnosis?

Carcinomatous ulcer. ### Explanation The correct diagnosis is **Carcinomatous ulcer** (Squamous Cell Carcinoma of the tongue). **1. Why it is correct:** In an elderly patient (60 years), a chronic ulcer on the **lateral margin of the tongue** is highly suspicious of malignancy. The key clinical feature here is the **referred otalgia (ear pain)**. The tongue is supplied by the lingual nerve (a branch of the mandibular nerve, V3). Malignant infiltration of the lingual nerve causes pain that is referred to the ear via the **auriculotemporal nerve** (also a branch of V3). This "referred pain" is a classic red flag for base of tongue or lateral tongue carcinoma. **2. Why other options are incorrect:** * **Dental ulcer:** These are usually acute, associated with a sharp tooth or ill-fitting denture, and typically heal once the source of trauma is removed. They rarely cause referred otalgia unless severely infected. * **Tuberculosis ulcer:** These are typically **exquisitely painful**, shallow, with undermined edges, and usually occur on the tip of the tongue in patients with active pulmonary TB. * **Syphilitic ulcer:** Primary syphilis (chancre) is painless and usually on the tip; tertiary syphilis (gumma) occurs on the **dorsum** of the tongue in the midline, not the lateral margin. **3. NEET-PG High-Yield Pearls:** * **Most common site** for oral cavity cancer: Lower lip (globally), but in India, it is the **buccal mucosa** (due to tobacco chewing). * **Most common site for tongue cancer:** Lateral border of the anterior two-thirds. * **Lymphatic spread:** Tongue tip drains to Submental nodes (Level Ia); Lateral tongue drains to Submandibular (Level Ib) and then to Jugulodigastric nodes. * **Trotter’s Triad** (for Nasopharyngeal Ca) also involves referred otalgia, but the tongue ulcer specifically points to V3 involvement.

Q: What is the most common primary malignant tumor of the parotid gland?

Mucoepidermoid carcinoma. **Explanation:** **Mucoepidermoid carcinoma (Option B)** is the most common primary malignant tumor of the parotid gland, as well as the most common malignant salivary gland tumor overall in both adults and children. It is characterized histologically by a mixture of mucus-secreting cells, epidermoid cells, and intermediate cells. Its prognosis depends heavily on the histological grade (low, intermediate, or high). **Analysis of Incorrect Options:** * **Warthin’s tumor (Option A):** This is the second most common **benign** tumor of the parotid gland (after Pleomorphic Adenoma). It is not malignant. It is strongly associated with smoking and is often bilateral or multicentric. * **Acinic cell carcinoma (Option C):** This is the second most common malignancy of the parotid gland. It is generally slow-growing and has a relatively better prognosis compared to other malignancies. * **Adenoid cystic carcinoma (Option D):** While this is the most common malignant tumor of the **submandibular and minor salivary glands**, it is less common in the parotid. It is notorious for **perineural invasion**, leading to pain and late recurrences. **High-Yield Clinical Pearls for NEET-PG:** * **Rule of 80s for Parotid:** 80% of salivary tumors occur in the parotid; 80% of parotid tumors are benign; 80% of those are Pleomorphic Adenomas. * **Most common benign tumor:** Pleomorphic Adenoma (all glands). * **Most common malignancy:** Mucoepidermoid carcinoma (Parotid and overall). * **Most common malignancy in Submandibular/Minor glands:** Adenoid cystic carcinoma. * **Malignancy Risk:** The smaller the salivary gland, the higher the risk of a tumor being malignant (Parotid < Submandibular < Sublingual).

Q: A cyst arising from an unerupted permanent tooth is termed:

Dentigerous cyst. ### Explanation **Correct Answer: A. Dentigerous cyst** A **Dentigerous cyst** (also known as a follicular cyst) is an odontogenic cyst that develops from the accumulation of fluid between the reduced enamel epithelium and the crown of an **unerupted or impacted tooth**. * **Pathophysiology:** It originates at the cemento-enamel junction (CEJ). As the cyst grows, it encloses the crown of the tooth while the root remains outside the cyst sac. * **Common Site:** The most frequently involved tooth is the **mandibular third molar**, followed by the maxillary canine. * **Radiology:** It typically appears as a well-defined, unilocular radiolucency surrounding the crown of an unerupted tooth. **Why other options are incorrect:** * **B. Epulis:** This is a non-specific clinical term for any tumor-like gingival swelling (e.g., fibrous epulis, pregnancy tumor). It is a soft tissue lesion, not a bony cyst associated with unerupted teeth. * **C. Odontogenic Keratocyst (OKC):** While also an odontogenic cyst, it arises from the **dental lamina** rather than the follicle of an unerupted tooth. It is known for its aggressive behavior, high recurrence rate, and association with **Gorlin-Goltz syndrome**. Unlike dentigerous cysts, OKCs often expand in an anteroposterior direction within the marrow. **High-Yield Clinical Pearls for NEET-PG:** * **Most common odontogenic cyst:** Radicular cyst (associated with a non-vital/carious tooth). * **Most common developmental odontogenic cyst:** Dentigerous cyst. * **Radiological sign:** "Snow-plow" effect (displacement of adjacent teeth). * **Complications:** If left untreated, a dentigerous cyst can transform into an **Ameloblastoma** or, rarely, Squamous Cell Carcinoma. * **Treatment:** Enucleation and extraction of the involved tooth.

Q: Which of the following head and neck tumors has the worst prognosis?

Adenoid cystic carcinoma. **Explanation:** The prognosis of salivary gland tumors depends on their histological grade, growth pattern, and tendency for local or distant spread. **Why Adenoid Cystic Carcinoma (ACC) is the correct answer:** Among the options provided, **Adenoid Cystic Carcinoma** is notorious for its aggressive biological behavior. While it is often slow-growing, it has a hallmark characteristic of **perineural invasion** (creeping along nerves), making complete surgical resection difficult and leading to high rates of local recurrence. Most importantly, it has a high propensity for **late distant metastasis** (most commonly to the lungs), which can occur even decades after initial treatment, resulting in a poor long-term survival rate. **Analysis of Incorrect Options:** * **Acinic Cell Carcinoma:** This is generally considered a low-grade malignancy with a relatively favorable prognosis and low metastatic potential compared to ACC. * **Cystadenolymphoma (Warthin’s Tumor):** This is a **benign** salivary gland tumor (typically involving the parotid). It has an excellent prognosis as it does not metastasize. * **Mucoepidermoid Carcinoma:** The prognosis here is highly variable depending on the grade. While high-grade variants are aggressive, the overall group includes many low-grade cases that have a much better prognosis than ACC. **High-Yield Clinical Pearls for NEET-PG:** * **Most common site for ACC:** Submandibular gland and minor salivary glands (palate). * **Histological appearance:** Classic "Swiss-cheese" or cribriform pattern. * **Nerve Involvement:** ACC is the most common tumor to cause facial nerve palsy in the parotid gland. * **Warthin’s Tumor:** Associated with smoking, often bilateral/multicentric, and shows "Hot spots" on Technetium-99m pertechnetate scan.

Question 1

A 70-year-old male presented with an asymptomatic white patch on the oral cavity following the application of a denture. What is the treatment of choice?

Accepted Answer

Ascertaining that the denture fits properly

Answer

Low dose radiotherapy

Answer

Biopsy of all the tissues

Answer

Antibiotics

Question 2

A 36-year-old male patient presents with swelling in the submandibular region, elevated tongue, and dysphagia. He has a high fever, and intraoral examination reveals a grossly destructed lower first molar. What is the likely cause of the high fever associated with this patient's condition?

Accepted Answer

All of the above

Answer

Septicemia

Answer

Reduced immunity

Answer

Severity of infection

Question 3

Which of the following is not always a true odontogenic infection?

Accepted Answer

Maxillary sinusitis

Answer

Periapical abscess

Answer

Periodontal abscess

Answer

None of the above

Question 4

In MPDS (Masticatory Muscle Pain Dysfunction Syndrome), which muscle is most commonly involved?

Accepted Answer

Lateral pterygoid

Answer

Masseter

Answer

Temporalis

Answer

Medial pterygoid

Question 5

Adenomatoid odontogenic tumour is most commonly found in which location?

Accepted Answer

Anterior maxilla

Answer

Anterior mandible

Answer

Posterior maxilla

Answer

Ramus of mandible

Question 6

A known HIV-infected patient presents with a non-tender parotid gland swelling. What is the most likely diagnosis?

Accepted Answer

Lymphoepithelial cysts

Answer

B-cell non-Hodgkin's lymphoma

Answer

Sialectasia

Answer

Parotid abscess

Question 7

A 60-year-old man presents with an ulcer on the lateral margin of his tongue, also complaining of ear pain. What is the most probable diagnosis?

Accepted Answer

Carcinomatous ulcer

Answer

Dental ulcer

Answer

Tuberculosis ulcer

Answer

Syphilitic ulcer

Question 8

What is the most common primary malignant tumor of the parotid gland?

Accepted Answer

Mucoepidermoid carcinoma

Answer

Warthin's tumor

Answer

Acinic cell carcinoma

Answer

Adenoid cystic carcinoma

Question 9

A cyst arising from an unerupted permanent tooth is termed:

Accepted Answer

Dentigerous cyst

Answer

Epulis

Answer

Odontogenic keratocyst

Answer

None of the above

Question 10

Which of the following head and neck tumors has the worst prognosis?

Accepted Answer

Adenoid cystic carcinoma

Answer

Acinic cell carcinoma

Answer

Cystadenolymphoma

Answer

Mucoepidermoid carcinoma

Diseases of the Oral Cavity and Salivary Glands — MCQs

Diseases of the Oral Cavity and Salivary Glands — MCQs

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