Fracture strength of Class II composite resin restorations.

T he superior physical properties of composite resins have aroused the possibility of their use beyond the accepted indications for acrylic resin and silicate cement. The literature has suggested the use of composite resin for Class I,‘m4 Class II,” and Class IV39 * restorations. Other reports advocated the use of composite resin or tested the influence of pins on the physical properties of composite resin.“, i Clinical tests which compared composite resin and amalgam for Class II restorations showed that, while amalgam retained its anatomic form, the composite resin had superior marginal integrity for as much as three years of service.5, 8, !’ Standards for strength have not yet been established for posterior restorations,5 despite the many tests conducted under standardized conditions in laboratories. This procedure avoids the complications found in clinical testing of restorations of various forms, sizes, and volumes. This report presents the results of a laboratory test of Class II composite restorations retained with and without cemented pins.