The marginal adaptation of four different bonding agents in Class II composite resin restorations applied in bulk or in two increments.

Class II cavities with two retention grooves at the cervical wall, situated at the cemento-enamel junction, were restored with Palfique Light Cured composite resin and one of four different bonding agents and one of two composite resin application techniques. In 80 restorations, any gap present was disclosed by the penetration of a fluorescent resin into the air-filled gap. In another 80 restorations a toluidine blue solution was used to reveal gaps. Tokuso Light Bond and Superbond C&B had poor marginal adaptation: gap formation was observed in 90.0% and 57.5% of those restorations, respectively. In contrast, All-Bond had a 20.0% rate and Superbond D-liner had a 12.5% rate of restorations with failures, represented by very thin gaps in the outer part of the cervical wall. Bulk application of the composite resin material and light curing from the cervical and axial walls through a plastic matrix strip gave results comparable to those of a two-stage horizontal application technique with light curing from the occlusal area and a metal matrix band.