Which of the following is true regarding the smear layer?

The smear layer is a thin film of debris and collagen produced when tooth surfaces are prepared (e.g., during cavity preparation). This layer can interfere with the bonding processes used in restorative dentistry.

The chosen answer, which states that the use of self-etching primers dissolves the smear layer, accurately reflects the function of these materials. Self-etching primers are designed to not only bond to dental tissues but also slightly demineralize the underlying dentin while simultaneously addressing the smear layer. They contain acidic components that effectively interact with this layer and help in its dissolution. This action facilitates better penetration of the bonding agents into the dentin, ultimately improving adhesion and retention of restorative materials.

In contrast, other options do not correctly describe the effects of self-etching systems on the smear layer. Although some materials are intended to remove or manipulate the smear layer, the specific action of dissolution by self-etching primers is distinct and critical for effective bonding in restorative procedures.