The use of composite resins in primary molars.

Composite resins were introduced to the dental profession nearly 15 years ago. Developed by Dr. Bowen at the National Bureau of Standards, and first marketed by the 3M Company of St. Paul, Minnesota, this new material was enthusiastically accepted by the dental profession. While this was clearly an improvement over the traditional silicate cement which had been on the market for almost 85 years, the first generation of composites exhibited a number of problems. Most significant among these were inadequate shading, variable setting-time, and solubility in alcohol. After resolving these deficiencies and further improving their mechanical properties, several manufacturers believed that composite resins could serve as a viable substitute for dental amalgam. Because of manufacturers’ strong recommendations, many clinicians began using composite resin in Class I and II cavity preparations in the mid-60s. The substitition of this material for amalgam was further encouraged by the 1971 results of a one-year clinical study conducted at the University of Indiana.’ In that study it was shown there was no significant difference in the wear rate of composite resin, Adaptic, a and the amalgam control, Velvalloy.b Furthermore, ditching, an unfavorable characteristic of amalgam restorations, was virtually absent in the composite resin restorations. Unfortunately, evaluation of these materials after two years revealed much less favorable results.5 In fact, at the end of 24 months the composite resins had undergone substantially greater loss in anatomical form than had the amalgam controls. A number of subsequent investigations confirmed these findings.3*Asaresultof these studies, most practitioners discontinued the use of composite resins in Class I and II cavity preparations. Until recently, no long-term well-controlled research has been reported on the use of composite resins in primary molars. However, Tonn, Ryge, and