Clinical performance of sealed composite restorations placed over caries compared with sealed and unsealed amalgam restorations.

The 2-year clinical evaluations of paired occlusal restorations are presented. Each study participant received a sealed composite restoration placed over a carious lesion and either a traditional outline-form (unsealed) amalgam or an ultraconservative sealed amalgam restoration. Caries was removed before placement of both types of amalgam restorations. No important clinical differences developed among the three groups of restorations.