Ceramic Inlays versus Composite Inlays

Acid etching and filled acrylic materials have been generating great interest in the past few years because of increased public demand for esthetic restorations and alternatives to amalgam. Composite resin and ceramic inlays, which use adhesive bonding, were introduced to make possible toothcolored restorations. The physical properties of composite resin restorations, and their poor wear resistance, have been known for a considerable time.1· 2 While heat-treated composite resin inlays exhibit significantly better homogeneity and marginal adaptation than conventional intraorally cured inlays, poor abrasion resistance and rapid degradation of the marginal integrity raised doubts as to their suitability for occlusal restorations. According to Marolf, composite resin inlays have a service life of 3 to 5 years. Whether composite inlays are suitable for occlusal restorations is still a controversial subject, especially since no longitudinal studies have been carried out to date. 3-? That exact primary marginal fit is possible was proved in numerous experimental and clinical studies.s-10 However, even improved systems cannot prevent disintegration at the inlaybonding composite interface after subjection to thermal and mechanical stresses or several months of intraoral service. 2. 5 . 11 The physical properties of porcelain and ceramic are comparable to those of dentin. The material is chemically inert; thermal expansion is similar to that of the tooth.12 Horn 13 and Calamia and Simonsen 14• 15 conclude that porcelain etching enhances retention and thus produces a clinically stable and durable blood with the dentin. While castable ceramic and composite inlays (indirect fabrication) are produced from an impression