A composite resin versus an amalgam: a study of certain properties and the design and initiation of a clinical investigation

Abstract

Certain properties of a representative composite material were evaluated by in vitro testing and compared to those of other types of restorative materials. A clinical study designed to evaluate the performance of the composite material as compared to amalgam for Class II restorations was initiated and one-year results are reported. Laboratory tests for abrasion resistance, hardness, marginal leakage, strength, color stability, staining characteristics, solubility, and water sorption were conducted. The clinical study is still in progress but the results after one year indicated that the composite resin test restorations, as well as the amalgam control restorations, were generally satisfactory. In overall clinical performance neither material was superior to the other. The amalgam restorations received a superior rating for anatomic form while the composite restorations were superior in terms of marginal adaptation. No clinical evidence of recurrent caries, associated with any of the restorations, was detected. Surface discoloration was a significant finding on the composite restorations, but it was confined to proximal areas and may be related to the difficulty of cleaning these areas with a toothbrush. No conclusions can yet be made regarding the long-term clinical performance of the composite resin used in this investigation as a Class II restorative material.