Effects of acids on pulp depends on

• A. Thickness of dentin between restoration and pulp
• B. Degree of etching
• C. Presence of smear layer
• D. Both A and B

Answer: (D)

Acid effects on the pulp depend on how much acid can reach the pulp, which is determined mainly by two things. First, the thickness of the dentin between the restoration and the pulp acts as a natural barrier; the thicker that dentin, the less acid diffuses through to dental pulp, protecting it from irritation. Second, how aggressively the dentin is etched matters because etching removes mineral content and exposes or opens dentinal tubules; more extensive etching increases permeability, allowing more acid to reach the pulp and potentially provoke a stronger pulpal response. The presence of a smear layer can modulate permeability, but the primary factors emphasized here are dentin thickness and degree of etching.