The Betel Quid Chewer

Correct answer: C. Xerostomia

• A. This IS an effect. The abrasive quid and the slaked lime cause mechanical and chemical irritation at the site where it is habitually parked, producing localized recession and mucosal ulceration.
• B. This IS an effect. The reddish-brown to black staining of teeth, gingiva and mucosa is the most visible sign and is the reason chewers are sometimes said to have 'betel-stained' mouths.
• C. CORRECT — this is the EXCEPTION. Areca nut contains ARECOLINE, a muscarinic agonist, which STIMULATES salivary secretion. Chewers characteristically have increased salivation and expectorate frequently. Xerostomia is the opposite of what occurs.
• D. This IS an effect, and the most serious. Arecoline stimulates fibroblast collagen production, producing OSMF: progressive blanching, palpable fibrous bands, burning on spicy food and eventually trismus. It is a potentially malignant disorder with a malignant transformation rate around 7–13%.

Note: Areca nut is an IARC Group 1 human carcinogen in its own right, with or without tobacco. Screen these patients carefully at every visit — palpate for fibrous bands and measure maximum opening.

Correct answer: D. Internal (non-vital, walking) bleaching

• A. External bleaching acts on the outer enamel and will lighten the ADJACENT teeth as much as or more than the affected one — the discrepancy can actually widen. It also does nothing for staining that originates within the dentine.
• B. A veneer requires irreversible facial enamel reduction and may still show the dark substrate through the porcelain without an opaquer. It is a reasonable fallback if bleaching fails.
• C. A crown removes the most tooth structure of any option and is not justified for a discoloured but otherwise INTACT crown. Reserve it for teeth that have lost substantial structure.
• D. CORRECT. This is intrinsic discoloration from pulpal haemorrhage products within the dentine of a SINGLE non-vital tooth. INTERNAL BLEACHING places the bleaching agent (sodium perborate with water, or carbamide peroxide) inside the pulp chamber, sealed under a temporary, and is refreshed every few days until the shade matches. It removes no tooth structure at all, which makes it the most conservative option by a wide margin. Success rates for traumatically discoloured non-vital teeth are high.

Note: Before internal bleaching, place a barrier — 2 mm of glass ionomer or RMGI over the gutta-percha at a level 1 mm apical to the CEJ. This is the single step that prevents external cervical resorption.

Correct answer: C. External cervical resorption

• A. Apical resorption relates to orthodontic force, periapical inflammation or trauma, not to a coronal bleaching agent.
• B. Ankylosis is the fusion of root to bone following loss of the periodontal ligament, typically after avulsion or severe luxation — an entirely different mechanism.
• C. CORRECT. EXTERNAL CERVICAL (invasive) RESORPTION is the recognised complication. Bleaching agent — particularly heated 30% hydrogen peroxide — diffuses through the dentinal tubules and out through the patent tubules at the cementoenamel junction, where the cemental covering is thin or absent in a substantial proportion of teeth. The resulting inflammation in the periodontal ligament initiates a clastic resorptive lesion at the cervical level, which is often silent until it is advanced.
• D. Internal resorption originates from the PULP and requires vital pulp tissue and odontoclasts within the canal. This tooth has no pulp.

Note: Two protective measures: the cervical barrier described above, and avoiding the heated thermocatalytic technique. Sodium perborate with water in a sealed chamber is both safer and effective.