Thirty-nine conventional posterior composite fillings were placed according to the three-sited light curing technique using Tetric, a fine hybrid composite material, and Syntac, a dentin adhesive. Six and 12 months later, the restorations were clinically evaluated using macrophotographs. A quantitative marginal analysis was also done immediately after placing the restorations and at the two recall intervals using a replica technique and an SEM. Contour, secondary caries, postoperative sensitivity and bulk fractures all rated "A" at 12 months. Marginal discoloration and color match were scored as 97% "A" and 3% "B". The SEM evaluation of the marginal adaptation showed 95% "continuous margin" initially and 93% at 6 months and 89% at 12 months. No statistical difference was found between the initial findings and the 12-month recall between premolars and molars, nor between small and large restorations. The overall performance of the new composite material during the 12-month observation period was satisfactory.