Composite resin-amalgam compound restorations.

Extensive silver amalgam restorations in premolars and molars occasionally require sacrifice of healthy unsupported enamel walls or cusps. A posterior composite resin-amalgam compound technique has been proposed to conserve these structures. Microleakage was high at the enamel-amalgam interface, moderate at the composite resin-silver amalgam and dentin-composite resin interfaces, and minimal between the inner enamel and the composite resin. Light microscopy and scanning electron microscopy demonstrated that marginal adaptation of the silver amalgam to the composite resin of the cusps was acceptable and that penetration of the inner etched enamel to the composite resin was complete.