Evaluation of the Effect of Surface Treatments on Shear Bond Strength of Repaired Silorane-based Composites

This study aimed to evaluate the shear bond strength (SBS) of silorane-based and methacrylate-based composites repaired by silorane-based composites after different surface treatments.
In total, 32 composite cylinders were provided from each of the two composites types (e.g., P90: P and Z350: Z). Cylinders were allocated to four different groups as follows: no surface treatments (Z1 and P1), silane application (Z2, P2), erbium laser irradiation (Z3, P3) and sandblasting with alumina particles (Z4, P4). Afterwards, the bonding component of P90 adhesive system was applied to all the prepared composite surfaces, followed by the repairing of all the samples with P90 cylinders. Moreover, SBS of the repaired surface was evaluated using the universal testing machine (UTM). Data analysis was performed using the one-way analysis of variance (ANOVA) and Tukey HSD (honest significant difference) test (P≤0.05).
In this study, the highest SBS values in each group (P and Z) were observed in the groups of P4 (40.23 MPA) and Z4 (51.19 MPA). However, the groups of P3 (20 MPA) and Z3 (46.16 MPA) obtained lower ranks. Silane application led to lower bond strength, compared to the other mentioned groups, and this difference was statistically significant (P Silorane-based composites could be used to repair either methacrylate- or silorane-based composites by choosing proper surface treatments. In this study, while sandblasting and laser irradiation significantly improved bond strength of two composites, silane application indicated no such influence on bond strength.