Objectives: To evaluate the marginal microleakage of Class II cavities restored with various types of composite resins.
Materials and Methods: Standard Class II slot cavities were prepared at the proximal surfaces of 40 intact premolars which were divided into 4 groups. Four types of composite resins (Esthet-X-Denstply, USA, FiltekTMZ350- 3M ESPE, USA, Beautifil- Shofu, Japan and Solare P-GC, Japan) were used to restore the slot cavities. All the specimens were thermocycled and immersed in 0.5% basic fuschin dye for 24 hours. The specimens were then sectioned in mesio-distal direction. The marginal microleakage at the occlusal and cervical margin was scored using the ISO microleakage scoring system. Data was entered using SPSS Version 12.0 and analyzed using STATA software programme.
Results and discussion: All composite resins exhibited worse microleakage at the cervical margin compared to occlusal margin. Esthet-X showed significantly better microleakage score at the occlusal margin compared to Beautifil and Solare P. FiltekTMZ350 and Beautifil showed mainly microleakage into enamel only at the occlusal margin. Solare P demostrated better resistance against microleakage at the cervical margin compared to other composite resin tested. Esthet-X, Filtek Z350 and Beautiful is not significantly different from each other in terms of microleakage at the cervical margin.
Conclusion: This study showed that none of the materials used in this study is able to eliminate microleakage. Composite resin restorations exhibited worse micorleakage at cervical margin in comparison to occlusal margin.