Marginal seal of cervical tooth-coloured restorations. A laboratory investigation of placement techniques

Incremental placement of composite resin has been suggested as a means of overcoming the contraction that occurs during polymerization of the composite material and as a consequence should allow an improved gingival dentine seal. Numerous incremental placement techniques for composite resin restorations have been documented in the literature. This study examined four different methods of placing Silux in class V cavities, located in the region of the cemento-enamel junction, and lined with Vitrabond. None of the placement methods used completely sealed either the enamel or dentine margins. Of the four techniques employed, the one which involved incremental placement of the gingival component first showed the least amount of leakage at the dentine margin. This result, however, was only significantly different from that of the bulk placement method. In the majority of cases where leakage did occur at the dentine margin, it progressed no further than the Vitrabond lining. It appeared that the high initial adherence to dentine of the light cured glass-ionomer cement prevented deeper penetration of the dye.