A clinical evaluation of occlusal composite and amalgam restorations: one- and two-year results

A two-year study was conducted to compare the qualitative advantages, if any, of a conventional, cold-curing composite resin to amalgam in occlusal Class I cavities in posterior teeth. The composite was placed into modified, conservative cavity preparations using the acid etch technique. Sixty-one pairs of contralateral restorations were evaluated. Forty-six percent of the amalgams and 42.6% of the composites were considered sound. The major deficiency of each material was rough or chipped margins of the amalgams (38%) and worn surfaces of the composites (26%). The use of conservative cavity preparations and the acid-etch technique with bonding agent and final glaze improved the longevity of the composite restorations compared to previous studies. However, the improvement does not suggest that this method will have a long-term effect on clinical success nor does it indicate that composite is superior to amalgam other than in marginal integrity and esthetics.