Internal adaptation of different bulk-fill composite resin restorations applied on a thin layer of resin-modified glass-ionomer cement in endodontically treated teeth

Aims: The aim of this study was to assess and compare the internal adaptation of several bulk-fill resins applied on a thin layer of glass cement in endodontically treated teeth. Materials and Methods: Thirty-two intact premolars were endodontically treated. On the gutta-percha a thin layer of resin-modified glass-ionomer cement (RMGIC) Ionoseal. The teeth were randomly divided into 4 groups (n=8): Control group (CG) - Adper Scotchbond Multi-Purpose/Filtek Z350XT ; (FBF) - Single Bond Universal/Filtek Bulk Fill; (SF) - OptiBond All-In-One/SonicFill, (TBF) - Tetric N-Bond Universal/Tetric N-Ceram Bulk Fill . Each tooth was sectioned, and replicas were analyzed with scanning electron microscopy (SEM). Gap dimensions were measured from the digital images. Data were analyzed using analysis of variance (ANOVA) and Tukey’s test (p<0.05). The gaps formed between the resins and the RMGIC, and between RMGIC and dentin, as well as the widths of gaps, were also evaluated. Results: TBF had the lowest percentage of gaps and SF the highest (p<0.05). In all groups, 100% of the specimens presented gaps between RMGIC and dentin. Conclusion: SF presented a greater incidence of gaps than TBF.