Punched-Out Papillae and a Tight Face

Correct answer: A. Incisional biopsy of the necrotic papillae

• A. CORRECT — this is the EXCEPTION. BIOPSY has no role in necrotizing ulcerative gingivitis. The diagnosis is CLINICAL, made on the triad of pain, interdental necrosis and bleeding. Biopsy is unnecessary, adds trauma to already necrotic tissue, and delays treatment. It is indicated only if the lesion fails to respond as expected, raising the possibility of another diagnosis.
• B. This IS appropriate and is the cornerstone of treatment. Gentle ultrasonic or hand debridement under topical or local anaesthesia removes the pseudomembrane and biofilm. Aggressive instrumentation on day one is avoided because the tissues are exquisitely tender.
• C. This IS appropriate here. Antibiotics are NOT routine for localized NUG, but are indicated where there are SYSTEMIC signs — fever, malaise, lymphadenopathy — which this patient has. METRONIDAZOLE is the drug of choice because it targets the fusospirochaetal anaerobic flora.
• D. This IS appropriate. Chlorhexidine gives chemical plaque control while mechanical cleaning is too painful to perform properly. Hydrogen peroxide rinses are also traditionally used.

Note: Predisposing factors form the classic mnemonic picture: stress, smoking, immunosuppression, malnutrition and poor oral hygiene. NUG in a patient with none of these should prompt HIV testing. Long-term: the interdental craters persist and often need gingivoplasty once acute symptoms settle.

Correct answer: C. Scleroderma (systemic sclerosis)

• A. Occlusal trauma also widens the PDL, but it does so LOCALLY at the teeth bearing the excessive load, and those teeth are typically MOBILE and often tender. This patient's widening is generalized and the teeth are firm.
• B. Osteosarcoma classically produces SYMMETRICAL widening of the PDL of a SINGLE tooth or a localized group, often with a sunburst periosteal reaction. It is localized and progressive, not generalized in a patient with known systemic sclerosis.
• C. CORRECT. Uniform, generalized WIDENING of the PDL space with teeth that remain FIRM and asymptomatic is the classic radiographic sign of SCLERODERMA. It results from excessive collagen deposition in the periodontal ligament. It is most obvious around the posterior teeth. The picture is completed by microstomia with radial perioral furrowing, a rigid tongue, xerostomia (secondary Sjögren occurs in a substantial proportion), dysphagia and reflux, and mandibular angle resorption in advanced disease.
• D. Periodontitis destroys the alveolar CREST, producing bone loss and pocketing. It does not widen the intact PDL space uniformly along the root.

Note: Dental management in scleroderma: MICROSTOMIA is the practical obstacle — short appointments, small instruments, paediatric trays, stretching exercises, and consider sectional impressions. Manage the xerostomia aggressively, elevate the chair for reflux, and expect wound healing to be slow.

Correct answer: C. Ridge lap (saddle) pontic

• A. The sanitary or hygienic pontic is held clear of the ridge entirely, allowing free passage of floss and a brush beneath it. It is the most cleansable design of all, and is used posteriorly in the mandible where aesthetics are not a concern.
• B. The ovate pontic sits in a surgically or provisionally developed concavity in the ridge. It gives the best aesthetics — the tooth genuinely appears to emerge from the tissue — and it IS cleansable with floss because the contact is convex and shallow.
• C. CORRECT. The RIDGE LAP or SADDLE pontic straddles the ridge, contacting both the buccal and the lingual slopes over a broad concave area. That concavity cannot be reached with floss or a proxy brush, so plaque accumulates against mucosa with no ability to clean it — the result is chronic inflammation, erythema and ulceration of the ridge. It is regarded as obsolete and should not be used.
• D. The modified ridge lap contacts only the BUCCAL slope, giving the appearance of emerging from the ridge while leaving the lingual surface open and cleansable. It is the standard aesthetic pontic for the anterior and premolar regions.

Note: The governing principle for every pontic: CONVEX tissue surface, point or small area contact, and full access for floss. Concavity against mucosa is what makes the saddle pontic unmanageable.

Correct answer: A. Buccinator

• A. The temporalis IS a muscle of mastication — it elevates and, through its posterior fibres, retrudes the mandible.
• B. CORRECT — this is the exception. The BUCCINATOR is a muscle of FACIAL EXPRESSION, innervated by the buccal branch of the FACIAL nerve (CN VII). It compresses the cheek against the teeth, keeping the food bolus on the occlusal table during chewing and preventing it from pooling in the vestibule. It assists mastication functionally but is not one of the four muscles of mastication.
• C. The masseter IS a muscle of mastication — the most powerful elevator, and the most superficial and easily palpated.
• D. The medial pterygoid IS a muscle of mastication — it elevates and protrudes and assists in lateral movement.

Note: The four muscles of mastication all derive from the FIRST branchial arch and are all innervated by the MANDIBULAR division of the trigeminal (V3): masseter, temporalis, medial pterygoid and lateral pterygoid. Nerve supply is the reliable way to separate them from the muscles of facial expression, which come from the SECOND arch and are supplied by CN VII.