Effects of the XR bonding system on microleakage.

Bonding of composite resins to dentin is generally less effective and less predictable than bonding to enamel. Several new dentin bonding agents have been developed to improve adhesion. One of these products, the XR Bonding System, includes a glass ionomer liner and a resin dentin adhesive. Our study found that the resin dentin adhesive (primer and bonding agent) did not reduce microleakage effectively. However, when used in combination with the glass ionomer liner, the resin bonding system allowed very minimal microleakage.