A patient with bulimia nervosa asks how to protect her teeth. What is the best advice?

Correct answer: B. Rinse with water or a sodium bicarbonate solution after purging, and delay brushing

• A. This is the single most damaging piece of advice you can give. Brushing acid-softened enamel abrades away the demineralized surface layer and dramatically accelerates tooth surface loss.
• B. CORRECT. Neutralize first, brush later. Rinsing with water or a bicarbonate solution raises the oral pH and clears gastric acid, while delaying brushing for at least 30–60 minutes allows the softened, demineralized enamel surface to rehardern before it is subjected to mechanical abrasion.
• C. Whitening pastes are typically more abrasive and address appearance rather than the erosive process.
• D. An acidic rinse compounds the problem — the aim is to raise pH, not lower it further.

Note: The complete answer combines them: neutralizing rinse immediately, delay brushing, use a soft brush with fluoride toothpaste, high-fluoride varnish or 5000 ppm paste, and — most importantly — a compassionate, non-judgemental referral for the eating disorder itself. The dentist is frequently the first clinician to detect bulimia from perimylolysis on the palatal surfaces of the maxillary anteriors.