The Effect of Different Treatment Protocols on Shear Bond Strength in Resin Composite Restoration Repair

Abstract Objectives: It was aimed to investigate the effect of different treatment protocols on shear bond strength in composite restoration repair in vitro. Materials and Methods: 120 specimens were prepared with micro-hybrid composite (Filtek Z250, 3M-ESPE, USA). The samples were randomly divided into 12 groups (n=10) after being subjected to thermal cycling test. No surface treatment was applied to Group 1, Group 2, Group 3 and Group 4. İn Group 5, Group 6, Group 7 and Group 8 were sandblasted with the Cojet device, and in Group 9, Group 10, Group 11 and Group 12 were treated with Er,Cr:YSGG laser. Universal adhesive was applied to the specimen surfaces in total or self-etch mode. The repair process was carried out usan Filtek Z250 or nano-filled composite (Filtek Ultimate, 3M-ESPE, USA). A universal testing machine measured the repair shear bond strength. The fracture types were evaluated by optical microscopy and SEM. Statistical analyses were performed using Kruskal-Wallis test and Mann-Whitney U test at 0.05 significance level. Results: The highest bond strength was obtained in the CoJet sandblasted specimens. Higher shear bond strength values were obtained when the universal adhesive was applied in total-etch mode (p<0.05). In addition, the use of universal adhesive in total-etch mode with Filtek Ultimate and the use of nano-filled resin composite as repair material caused an increase in repair shear bond strength values. Clinical Significance: The findings of this study will guide the management of the repair procedure process.