Marginal adaptation in enamel and cement of composite inlays

Objectives: The aim of this study is to evaluate the marginal adaptation in enamel and radicular cement of composite inlays. This type of restorations improve the quality of the tooth–restoration interface, also in difficult situations. The extra-oral post-polymerization improves the mechanical properties of the restoration and limits the polymerization-shrinkage only to the thin layer of luting composite avoiding the gap formation that represents the greater limit to the use of composite in posterior teeth. Methods: 10 extracted premolars were prepared for composite inlays.In 5 teeth (Group A) the cervical margin was placed within enamel and in the other 5 teeth (Group B) the proximal boxes ended beyond the cemento-enamel junction. Impressions of each cavity were taken and all the restorations were fabricated with a laboratory light-polymerized microhybrid composite (Sinfony 3M-Espe) following the manufacturer's instructions. All the inlays were adhesively luted using a nanofilled composite (Filtek Supreme 3M-Espe). For this purpose the teeth were etched and conditioned. The inner surfaces of the indirect restorations were sandblasted, silanized and then brushed with bonding agent. The cavity was covered with a thin layer of composite and the inlay was seated. Gross excess material was removed and the specimens were light-polymerized. After the polymerization procedure was completed, remaining excess of composite was removed using flexible polishing discs.Both enamel-restoration interface and radicular cement-restoration interface evaluations were conducted by scanning electron microscopy (Jeol Jsm-s6001V.) . Results: The data analysis shows no gap at the tooth-restoration interface in the specimens of group A, while a marginal gap was found in one specimen of group B. Conclusion: According to the investigation in this study composite inlays and the described luting technique demonstrate to be reliable and useful also in critical situations (cervical margin in radicular cement).