Bonding agents placed on dentin have what effect on cytotoxicity?

• A. Increases
• B. Reduces
• C. No effect
• D. Unknown

Answer: (B)

Bonding agents on dentin primarily act as a barrier that lowers the amount of toxic substances reaching the dental pulp. They infiltrate the dentin enough to seal the dentinal tubules and create a resin-dentin interface that reduces permeability and diffusion of residual monomers and other irritants from the adhesive and restorative materials. By limiting diffusion and microleakage, the exposure of odontoblasts and pulp tissue to potentially cytotoxic components is decreased, lowering cytotoxic risk. Of course, this protective effect depends on proper bonding technique and complete polymerization; if the layer is poorly cured or damaged, some cytotoxic components can still reach the pulp.