Clinical evaluation of a heat-treated resin composite inlay: 3-year results

The purpose of this study was to evaluate a resin composite inlay system in clinical trials involving human subjects. A total of 60 restorations were inserted equally in Class I and II preparations and in premolars and molars. A glass ionomer liner was applied to the dentin. Light-cured direct inlays were fabricated in the oral environment. Thirty inlays were heat-treated for 7.5 minutes at 125 degrees C in a dry heat oven. Enamel margins of the preparations were etched with 37% phosphoric acid gel. All inlays were cemented with a light-cured enamel bonding resin. Restorations were evaluated using the USPHS system and M-L indirect scale. Six, 12, 24 and 36-month recalls were compared to baseline. Color, interfacial staining, secondary caries, and wear were unchanged from baseline for all restorations. Marginal integrity and surface texture show a differential change from baseline and with respect to restoration type. Indirect wear was not significantly different between restoration types (P < 0.05). Wear resistance was not significantly improved with heat treatment, but marginal integrity and surface characteristics showed marked improvement in the heat-treated group at 24 and 36-month recalls.