Marginal breakdown of 5-year-old direct composite inlays

Objectives: The marginal fit of tooth-coloured inlays luted with composite resin luting materials has been considered to be the weak link of the inlays. The marginal breakdown of 5-year-old direct composite resin inlays was evaluated by scanning electron microscopy. Methods: Replica impressions were made of the occlusal, axial-proximal and accessible cervical-proximal margins of 21 inlays and the marginal quality was quantified. Results: More than 84% of the total investigated length of the enamel/luting composite agent-luting composite/composite inlay interfaces revealed gap free margins. Proximal margins showed the largest breakdown at the enamel/composite resin interface, while the occlusal margin interfaces showed only a slight difference between the interfaces. The composite inlay and the luting composite resin showed a similar degree of wear in more than 50% of the evaluated marginal length. Medium gap width varied between 60 μm for the occlusal and axial-proximal and 87 μm for the cervical-proximal margins, with a range of 7.6–266 μm. Conclusion: The direct composite inlays investigated showed good marginal integrity after 5 years in clinical service.