An amalgam restoration has a 0.5 mm marginal deficiency but no recurrent caries, no pain and no fracture. What is the appropriate management?

Correct answer: B. Monitor and reassess at recall

• A. Replacement is over-treatment for an asymptomatic restoration functioning well without recurrent caries.
• B. CORRECT. Marginal ditching of this magnitude is common, and the evidence is clear that it does NOT predict caries. Amalgam self-seals through corrosion products. Replacing a serviceable restoration removes sound tooth structure, enlarges the preparation, and starts the restorative cycle that ends in a crown or a root canal. Monitoring is the conservative and correct choice.
• C. Repair is reserved for larger defects, fractured margins or localised recurrent caries — not for minor ditching.
• D. Sealing an amalgam margin with flowable composite is not an evidence-supported intervention here.

Note: The threshold usually cited is 0.5 mm. Beyond that, or where an explorer catches a definite defect with recurrent caries, repair rather than wholesale replacement is generally preferred.