The purpose of this study was to evaluate a dentinal bonding system through a follow-up investigation over a 2-year period of clinical performance. An experimental composite resin and the dentinal bonding system were applied to 108 teeth. Each restoration was examined at baseline, 1 week, 1 month, 3 months, 6 months, 1 year, and 2 years. No secondary caries or severe pulpitis was detected at any of the recall examinations. Only nine of 108 restorations were found to be unacceptable after 2 years. The dentinal bonding system showed relatively good clinical results and may prove to be useful clinically.