What thickness of dentin is associated with reduced pulpal irritation from resin composites?

• A. 0.1 mm
• B. 0.5 mm
• C. 1.0 mm
• D. 2.0 mm

Answer: (B)

Dentin thickness acts as a diffusion barrier that limits how much resin-related irritants reach the pulp. About half a millimeter of dentin provides a meaningful barrier, significantly reducing the diffusion of resin monomers and other components toward the pulp during bonding and curing, which lowers pulpal irritation. If the dentin is thinner than this, more irritants can reach the pulp; if it’s thicker, the protective effect is greater, though clinical practice recognizes roughly half a millimeter as the practical threshold for reduced irritation. When remaining dentin is very thin, using a liner or dentin substitute to shield the pulp is often indicated to further protect it.