In resin-dentin bonding, what is the final step to complete the bonding process?

• A. Light-cure to form the hybrid layer
• B. Etch with phosphoric acid
• C. Rinse and dry
• D. Apply primer

Answer: (A)

The bonding step is completed when the adhesive layer is polymerized. Light-curing the infiltrated adhesive initiates polymerization, creating the resin-dentin hybrid layer that locks the resin to the dentin’s collagen network. This cured network provides the durable, interlocked bond needed for the composite to adhere properly.

Etching with phosphoric acid prepares the surface by creating micro porosities, rinsing and drying remove debris and set up the surface, and applying primer wets and primed the dentin for bonding. However, none of these alone completes the bond; it is the light-curing that solidifies the adhesive layer and finishes the bonding process.