Cavity wall adaptation of resin based composites lined with flowable composites

Purpose: To compare the adhesion of a flowable resin-based composite (RBC) vs. a condensable RBC to tooth structure using scanning electron microscopy (SEM). Materials and Methods: Fifteen recently extracted human teeth were prepared for Class I restorations and equally divided into three groups. Gr oup I was filled with Heliomolar bonded with Syntac Single Component. Group 2 was lined with Flow-It in addition to ALERT condensable RBC bonded with Bond-1 Primer/Adhesive. Group 3 was filled with ALERT bonded with Bond-1 Pr imer/Adhesive. All teeth were thermocycled, sectioned and evaluated for gap formation with the SEM. Results: SEM at x15 demonstrated that restorations with the flowable RBC at the tooth/restoration interface showed no evidenc e of marginal gaps between the RBC material or at the underlying tooth stru cture. A significant difference (P< 0.05) in wall adaptation was found betw een Groups 2 and 3.