Cervical microleakage in MOD restorations: in vitro comparison of indirect and direct composite

This study compared microleakage between indirect composite inlays and direct composite restorations. Forty-eight standard inlay MOD cavities, with cervical margins located either in enamel or dentin, were prepared in extracted human third molars. The specimens were randomly divided into 3 groups (n=16). In the control group, the cavities were restored with the composite Filtek Z250 (3M ESPE). For the experimental groups, indirect restorations were made with the Artglass (Heraeus-Kulzer) or Belleglass HP (Kerr Laboratories) systems and cemented with the dual curing cement RelyX ARC (3M ESPE). The adhesive system Single Bond (3M ESPE) was applied on all groups. The specimens were submitted to thermolcycling, coated with nail varnish, then immersed in 2% basic fuchsine aqueous solution for 24 hours. The teeth were then sectioned and leakage scores were evaluated (40x), based on a standard ranking. Data were submitted to statistical analysis (Mann-Whitney and Kruskal-Wallis tests) with a 95% confidence level. No statistical difference was found between substrates (p=0.595), and the materials performed similarly in dentin (p=0.482). Direct restorations showed higher leakage than indirect restorations at the enamel margins (p=0.004). Within the limitations of this experimental design, overall leakage was similar between both substrates, while the indirect systems provided a better sealing than direct composites only in enamel.