A deep mesio-occlusal lesion closely approaches the pulp of a vital, asymptomatic tooth. What is the best management?

Correct answer: B. Remove infected dentin, leave affected dentin over the pulp, place a liner and restore

• A. Complete excavation to hard dentin in a deep lesion converts a restorable vital tooth into a pulp exposure requiring endodontic treatment. The evidence now clearly favours the conservative approach.
• B. CORRECT. Selective (partial) caries removal is the current standard for deep lesions in vital, asymptomatic teeth. Infected dentin is soft, wet and heavily contaminated and must go. Affected dentin is firm, discoloured but demineralized rather than infected, remains remineralizable, and is left over the pulp to avoid iatrogenic exposure. Seal it well and the lesion arrests.
• C. Root canal treatment on a vital, asymptomatic tooth with an intact pulp is unwarranted over-treatment.
• D. Extraction of a restorable tooth is indefensible here.

Note: How to tell them apart: INFECTED dentin is soft, easily removed with a spoon excavator, wet, and stains with caries detector. AFFECTED dentin is firm, resists the excavator, dry, and is often darker but sound. The peripheral rule matters too — you must reach hard dentin at the ENAMEL-DENTIN JUNCTION and all cavity margins to achieve a proper seal, even while leaving softer dentin pulpally.