Microleakage and adaptation of Class II packable resin-based composites using incremental or bulk filling techniques

Purpose: To compare the ability of three packable resin-based composite (RB C) systems (ALERT, SureFil, and Solitaire), placed and light-cured in eithe r incremental layers or in bulk, to seal the gingival margin of Class II pr eparations when the gingival margin is placed apical to the cementoenamel j unction. Materials and Methods: Packable RBCs were used to restore 60 extra cted human premolars with Class II preparations using an incremental-cure t echnique (each layer no greater than 2 mm in thickness when light-cured) or a bulk-cure technique (n=10). Manufacturers' directions were followed; the cure technique was the only variable. After the restorations were complete d, the specimens were thermocycled, stained, sectioned, and viewed under a light microscope for microleakage at the gingival margin. Results: All spec imens showed leakage at the gingival margin. No statistically significant d ifference was found between the bulk-cure and incremental-cure techniques f or each of the RBC systems evaluated. ALERT had significantly less leakage than SureFil and Solitaire.