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 161: What is MCS classification used for?

A. Oncology
B. Medical risk assessment (Correct Answer)
C. Major salivary gland
D. Mentally challenged subjects

Explanation: **Explanation:** The **MCS Classification** (Medical, Cardiac, and Surgical) is a clinical tool used for **medical risk assessment**, specifically in the context of minor oral surgical procedures or dental treatments. It helps clinicians categorize patients based on their systemic health status to determine if they can safely undergo a procedure in an outpatient setting or if they require hospitalization and specialized monitoring. * **M (Medical):** Refers to the patient's general medical status and systemic diseases (e.g., uncontrolled diabetes). * **C (Cardiac):** Specifically evaluates cardiovascular stability (e.g., history of MI, hypertension). * **S (Surgical):** Assesses the complexity and duration of the planned surgical procedure. **Analysis of Options:** * **A. Oncology:** Cancer staging typically uses the TNM (Tumor, Node, Metastasis) system. MCS is not used for grading or staging malignancies. * **C. Major salivary gland:** While MCS sounds like it could relate to "Major Salivary," classifications for salivary glands usually involve the TNM system for tumors or the Freudenthal/Stennert systems for sialadenitis. * **D. Mentally challenged subjects:** While these patients require special care, there is no standardized "MCS" classification specifically for mental disability assessment in ENT/Dentistry. **Clinical Pearls for NEET-PG:** * The MCS system is often compared to the **ASA (American Society of Anesthesiologists) Physical Status Classification**, but MCS is more tailored toward the specific interplay between a patient's systemic health and the surgical stress of oral procedures. * **High-Yield Tip:** For NEET-PG, always associate "MCS" with **pre-operative risk stratification** in oral surgery. * Remember that for major ENT surgeries, the **ASA classification** remains the gold standard for perioperative risk assessment.

Question 162: What is the most common cause of clicking in the temporomandibular joint?

A. Disc displacement with reduction (Correct Answer)
B. Disc displacement without reduction
C. Hypermobility
D. Loose articular bodies

Explanation: **Explanation:** The temporomandibular joint (TMJ) is characterized by a fibrocartilaginous disc situated between the condyle and the glenoid fossa. **1. Why Option A is Correct:** **Disc displacement with reduction (DDWR)** is the most common cause of TMJ clicking. In this condition, the disc is displaced anteriorly when the mouth is closed. Upon opening, the condyle moves forward and "jumps" back onto the thick posterior band of the disc. This sudden realignment (reduction) creates the characteristic **audible click**. A second "reciprocal click" often occurs during closing when the disc slips anteriorly again. **2. Why the other options are incorrect:** * **Disc displacement without reduction:** Here, the disc remains permanently displaced anterior to the condyle. Because the disc never "reduces" or snaps back into place, there is **no clicking**. Instead, patients present with a limited mouth opening (closed lock) and a "thud" or crepitus. * **Hypermobility:** This refers to subluxation or dislocation where the condyle moves beyond the articular eminence. While it can cause a "clunk," it is less common than DDWR and involves a different mechanical failure. * **Loose articular bodies:** Also known as "joint mice" (often due to synovial chondromatosis), these cause mechanical interference or locking, but are rare compared to internal disc derangements. **Clinical Pearls for NEET-PG:** * **Most common TMJ disorder:** Myofascial Pain Dysfunction Syndrome (MPDS), which is psychogenic/muscular. * **Clicking vs. Crepitus:** Clicking suggests internal derangement (DDWR); **Crepitus** (grating sound) suggests bone-on-bone contact, typical of **Osteoarthritis**. * **Management:** Most cases of clicking are managed conservatively with NSAIDs, soft diet, and occlusal splints. Surgery is rarely indicated.

Question 163: What is the other name for a \"Bay cyst\"?

A. Periapical cyst
B. Lateral periodontal cyst
C. Radicular cyst (Correct Answer)
D. Dentigerous cyst

Explanation: **Explanation:** A **Radicular cyst** (also known as a **Periapical cyst**) is the most common inflammatory odontogenic cyst. It arises from the **epithelial rests of Malassez** in the periodontal ligament as a result of inflammation following dental caries and pulp necrosis. The term **"Bay cyst"** refers specifically to a morphological variant of a radicular cyst where the cystic lumen is open to the root canal of the involved tooth, resembling a "bay" or an indentation. This is clinically significant because such cysts may resolve following conventional root canal treatment (nonsurgical endodontics), whereas a "true" radicular cyst (completely enclosed by epithelium) usually requires surgical intervention. **Analysis of Options:** * **Option A (Periapical cyst):** While this is a synonym for a radicular cyst, the specific term "Bay cyst" is a subtype/description used within the context of radicular pathology. In most exams, Radicular cyst is the preferred academic term. * **Option B (Lateral periodontal cyst):** This is a developmental (non-inflammatory) cyst located on the lateral aspect of the tooth root, typically in the mandibular premolar area. * **Option D (Dentigerous cyst):** Also known as a **follicular cyst**, it originates from the reduced enamel epithelium and surrounds the crown of an **unerupted tooth** (most commonly the 3rd molar). **High-Yield Pearls for NEET-PG:** * **Most common odontogenic cyst:** Radicular cyst. * **Origin:** Epithelial rests of Malassez. * **Radiological appearance:** Well-defined unilocular radiolucency at the apex of a non-vital tooth. * **Rushton bodies:** Eosinophilic, linear, or curved structures found in the epithelial lining of radicular cysts (highly characteristic).

Question 164: Pleomorphic adenomas (mixed tumors) of the salivary glands are characterized by which of the following?

A. They occur most commonly on the lips, tongue, and palate. (Correct Answer)
B. They grow rapidly.
C. They rarely recur if simply enucleated.
D. They present as rock-hard masses.

Explanation: **Explanation:** **Pleomorphic Adenoma (Mixed Tumor)** is the most common benign tumor of both major and minor salivary glands. 1. **Why Option A is correct:** While the parotid gland is the most common site overall (major glands), the **minor salivary glands** are also frequently involved. Among minor salivary glands, the **palate** is the most common site, followed by the **lips** (upper lip > lower lip) and the **tongue**. This makes Option A the most accurate description of its distribution in the context of minor glands. 2. **Why other options are incorrect:** * **Option B:** These tumors are characteristically **slow-growing**, often present for years before the patient seeks medical attention. Rapid growth should raise suspicion of malignant transformation (*Carcinoma ex pleomorphic adenoma*). * **Option C:** They have a high recurrence rate if "simply enucleated." This is due to **pseudopod-like extensions** (microscopic projections) that penetrate the capsule. The standard treatment is **Superficial Parotidectomy** (for parotid tumors) or wide local excision with a margin of healthy tissue to prevent recurrence. * **Option D:** They typically present as **firm, mobile, and painless** masses. A "rock-hard" consistency or fixation to skin/underlying structures usually indicates malignancy. **High-Yield Clinical Pearls for NEET-PG:** * **Histology:** Shows a "mixed" appearance—epithelial elements (ducts/acini) and mesenchymal-like elements (myxoid, chondroid, or osteoid stroma). * **Most common site:** Parotid gland (specifically the superficial lobe). * **Nerve involvement:** Facial nerve palsy is **rare** in pleomorphic adenoma; its presence strongly suggests a malignant tumor like Adenoid Cystic Carcinoma. * **Hot Tip:** If a question mentions a "painless, slow-growing swelling at the angle of the jaw," always think Pleomorphic Adenoma first.

Question 165: A 32-year-old female patient underwent extraction of an upper first molar on the right side, resulting in a 0.3 mm perforation of the sinus wall. Oroantral communication is predominantly seen during the extraction of which teeth?

A. Maxillary premolars
B. Maxillary first molars (Correct Answer)
C. Maxillary second molar
D. Maxillary paramolar

Explanation: **Explanation:** The **maxillary first molar** is the most common tooth associated with the formation of an oroantral communication (OAC). This is primarily due to the anatomical proximity of its roots to the floor of the maxillary sinus (antrum of Highmore). In many adults, only a thin layer of bone—or sometimes just the sinus mucosa—separates the trifurcated roots of the first molar from the sinus cavity. During extraction, the divergent nature of these roots increases the risk of fracturing the thin antral floor. **Analysis of Options:** * **Maxillary First Molar (Correct):** Statistically the most frequent site for OAC because its roots are the longest and most closely related to the lowest point of the sinus floor. * **Maxillary Second Molar:** While also in close proximity to the sinus, it is the second most common site. The roots are often less divergent than the first molar. * **Maxillary Premolars:** The second premolar is frequently near the sinus, but the first premolar is usually further anterior, making OAC less common. * **Maxillary Paramolar:** These are supernumerary teeth. While they can cause complications, they are rare compared to the standard dentition. **Clinical Pearls for NEET-PG:** * **Definition:** An OAC is a physical communication between the oral cavity and maxillary sinus. If it persists and becomes epithelialized, it is termed an **Oroantral Fistula (OAF)**. * **Management Rule of Thumb:** * **< 2 mm:** Usually heals spontaneously with a blood clot; advise sinus precautions (no nose blowing). * **2–6 mm:** Requires figure-of-eight sutures and Gelfoam to maintain the clot. * **> 6 mm:** Requires surgical closure (e.g., **Berger’s Buccal Advancement Flap** or Palatal Rotation Flap). * **Diagnosis:** Positive **nose-blowing test** (escape of air/bubbles through the socket).

Question 166: Oral submucous fibrosis is diagnosed by which of the following findings?

A. Juxtaepithelial fibrosis
B. Changes in epithelium
C. Changes in submucosa
D. All of the above (Correct Answer)

Explanation: **Explanation:** Oral Submucous Fibrosis (OSMF) is a chronic, progressive, premalignant condition characterized by inflammation and progressive fibrosis of the oral soft tissues. The diagnosis is based on a combination of clinical features and characteristic histopathological changes involving both the epithelial and connective tissue layers. **Why "All of the above" is correct:** 1. **Juxtaepithelial Fibrosis (Option A):** This is the hallmark of OSMF. There is excessive collagen deposition in the juxtaepithelial area, leading to hyalinization. This fibrosis causes the characteristic "blanching" of the mucosa and the formation of palpable vertical bands. 2. **Changes in Epithelium (Option B):** The epithelium typically undergoes **atrophy** (thinning) with the loss of rete pegs. In some cases, there may be hyperkeratosis or varying degrees of epithelial dysplasia, which contributes to its premalignant potential. 3. **Changes in Submucosa (Option C):** Beyond the juxtaepithelial layer, the deeper submucosa shows increased vascularity in early stages, followed by decreased vascularity (ischemia) in later stages due to dense fibrosis. There is also an infiltration of inflammatory cells (plasma cells and lymphocytes). **Clinical Pearls for NEET-PG:** * **Etiology:** Strongly associated with **Areca nut (Betel nut)** chewing. * **Clinical Presentation:** Progressive inability to open the mouth (Trismus), burning sensation on eating spicy food, and "Hockey-stick" appearance of the uvula. * **Premalignant Potential:** OSMF has a high malignant transformation rate (approx. 7–13%), most commonly leading to **Squamous Cell Carcinoma**. * **Treatment:** Cessation of habit, intralesional steroids (Hyaluronidase/Dexamethasone), and surgical release of bands in advanced cases.

Question 167: What is the most common causative organism of acute suppurative parotitis?

A. Staphylococcus aureus (Correct Answer)
B. Streptococcus pyogenes
C. Corynebacterium
D. None of the above

Explanation: **Explanation:** **Acute Suppurative Parotitis** is a bacterial infection of the parotid gland, typically occurring in patients with dehydration, poor oral hygiene, or those in the postoperative period (traditionally called "Surgical Mumps"). **1. Why Staphylococcus aureus is correct:** *Staphylococcus aureus* is the most common causative organism isolated in acute suppurative parotitis. The pathogenesis involves the retrograde migration of oral flora into the Stensen’s duct, usually facilitated by reduced salivary flow (stasis). Since *S. aureus* is a prominent member of the oral flora and possesses virulence factors that allow it to thrive in the stagnant protein-rich saliva, it becomes the primary pathogen. **2. Why other options are incorrect:** * **Streptococcus pyogenes:** While Streptococci (including *S. viridans* and *S. pneumoniae*) can cause sialadenitis, they are significantly less common than *S. aureus*. * **Corynebacterium:** These are generally commensals of the skin and mucous membranes and are rarely implicated as primary pathogens in acute parotid infections. **High-Yield Clinical Pearls for NEET-PG:** * **Risk Factors:** Dehydration (most common), debilitation, use of anticholinergic drugs, and ductal obstruction (sialolithiasis). * **Clinical Presentation:** Sudden onset of firm, erythematous, and exquisitely tender swelling over the parotid region. Purulent discharge may be seen from the opening of the Stensen’s duct (opposite the upper second molar) upon massaging the gland. * **Management:** Rehydration, intravenous antibiotics (covering penicillinase-producing *S. aureus*), and sialogogues (to stimulate saliva flow). * **Complication:** If an abscess forms and medical management fails, **Hilton’s Method** (incision and drainage) is performed to avoid damaging the facial nerve.

Question 168: Ameloblastoma most frequently occurs in which anatomical region?

A. Mandibular molar region (Correct Answer)
B. Maxillary molar region
C. Mandibular premolar region
D. Maxillary premolar region

Explanation: **Explanation:** **Ameloblastoma** is the most common benign (but locally aggressive) odontogenic tumor. It arises from the dental epithelium (enamel organ, remnants of Malassez, or the lining of odontogenic cysts). 1. **Why Mandibular Molar Region is Correct:** Statistically, approximately **80% of ameloblastomas occur in the mandible**, while only 20% occur in the maxilla. Within the mandible, the **molar-ramus area** is the most frequent site of involvement (70-75%). This is attributed to the high concentration of odontogenic epithelial remnants in this region during tooth development. 2. **Analysis of Incorrect Options:** * **Maxillary Molar Region:** While the maxilla is the second most common site, it accounts for a significantly smaller percentage of cases. Maxillary tumors are often more dangerous as they can invade the maxillary sinus and skull base. * **Mandibular/Maxillary Premolar Regions:** Although these tumors can occur in the premolar or anterior regions (symphysis), they are far less frequent than the posterior mandibular involvement. **Clinical Pearls for NEET-PG:** * **Radiological Appearance:** Classically described as a **"Soap-bubble"** or **"Honey-comb"** multilocular radiolucency. * **Clinical Feature:** It causes painless, slow-growing expansion of the jaw, often leading to **bony thinning (Egg-shell crackling)** and root resorption of adjacent teeth. * **Histopathology:** The most common patterns are **Follicular** and **Plexiform**. * **Treatment:** It is locally invasive with a high recurrence rate; therefore, wide local excision with clear margins (segmental resection) is the treatment of choice rather than simple curettage.

Question 169: Which stain is used for detecting early cancer in the oral and pharyngeal cavity?

A. Silver nitrate
B. Toluidine blue (Correct Answer)
C. Congo red
D. Zinc chloride

Explanation: **Explanation:** **Toluidine Blue (Option B)** is a basic thiazine metachromatic dye that has a high affinity for acidic tissue components, specifically **nucleic acids**. In dysplastic and malignant cells, there is an increase in DNA content (hyperchromatism) and rapid cell division. When applied topically to the oral mucosa, the dye selectively binds to these areas of high DNA density, staining them dark blue. This makes it an excellent screening tool for identifying suspicious "occult" lesions or demarcating the margins of early squamous cell carcinoma that may not be clearly visible to the naked eye. **Why the other options are incorrect:** * **Silver nitrate (Option A):** Primarily used as a cauterizing agent for aphthous ulcers or to control epistaxis (Little’s area). It is not a diagnostic stain for malignancy. * **Congo red (Option C):** This is the gold standard stain for **Amyloidosis**, showing characteristic "apple-green birefringence" under polarized light. * **Zinc chloride (Option D):** Historically used as a chemical fixative or caustic agent; it has no role in the vital staining of cancerous tissues. **High-Yield Clinical Pearls for NEET-PG:** * **Vital Staining:** Toluidine blue is a "vital stain," meaning it is applied to living tissue. * **False Positives:** Inflammatory conditions (like oral candidiasis or trauma) can also take up the stain due to increased cellular turnover, leading to false positives. * **Schiller’s Test:** Do not confuse this with the Lugol’s iodine test used for the cervix; however, Lugol’s iodine can also be used in the oral cavity to identify "iodine-negative" (malignant) areas. * **Biopsy Gold Standard:** While Toluidine blue helps in screening, a **punch biopsy** remains the definitive gold standard for diagnosing oral cancer.

Question 170: Oral dyskinesia may be caused by which of the following?

A. Complete loss of teeth (Correct Answer)
B. TMJ ankylosis
C. Herpes simplex infection
D. Pemphigus vulgaris

Explanation: **Explanation:** **Oral dyskinesia** (also known as orofacial dyskinesia) refers to involuntary, repetitive, and purposeless movements of the tongue, lips, and jaw. **Why "Complete loss of teeth" is correct:** The loss of all natural teeth (edentulism) leads to a loss of **proprioceptive feedback** from the periodontal ligaments. This sensory deficit, combined with the collapse of the vertical dimension of the face and alveolar bone resorption, can trigger abnormal neuromuscular patterns. In elderly patients, this is specifically termed **"Edentulous Dyskinesia."** Providing well-fitted dentures often helps stabilize the jaw and reduce these involuntary movements. **Why the other options are incorrect:** * **TMJ Ankylosis:** This results in a mechanical restriction of joint movement (trismus/locked jaw), rather than involuntary hyperkinetic movements. * **Herpes Simplex Infection:** This causes painful vesicular eruptions (stomatitis). While pain may limit movement, it does not cause a dyskinetic movement disorder. * **Pemphigus Vulgaris:** This is an autoimmune blistering disorder of the mucous membranes. It presents with painful erosions and Nikolsky’s sign, but does not affect the neuromuscular control of the jaw. **High-Yield Clinical Pearls for NEET-PG:** * **Tardive Dyskinesia:** The most common cause of oral dyskinesia is the long-term use of **antipsychotics** (Dopamine receptor blockers). * **Meige Syndrome:** A combination of oral dyskinesia and blepharospasm (involuntary eyelid closure). * **Ill-fitting dentures:** While edentulism causes dyskinesia, poorly fitting dentures can exacerbate the condition by causing constant "fumbling" movements to keep the prosthesis in place.

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

Want unlimited practice?

Get full access to all questions, explanations, and performance tracking.

Start For Free