effect of adhesive type and silane application on the repair bond strength of aged bulk-fill composites

Objective: this study evaluated the effects of different adhesive strategies and silane application on the repair bond strength of bulk-fill composites.methods: seventy specimens were prepared using a bulk-fill condensable composite. after thermocycling, they were randomly divided into five groups (n = 14) based on the bonding protocol: group 1: gluma bond 5 (two-step etch-and-rinse), group 2: silane + gluma bond 5, group 3: gluma bond universal (self-etch mode), group 4: silane + gluma bond universal (self-etch mode), and group 5: gluma bond universal (etch-and-rinse mode). the repair process involved treating the aged composite surface according to the assigned adhesive protocol, after which bulk-fill composite was placed in molds positioned against the treated surface to complete the restoration. shear bond strength (sbs) was measured using a universal testing machine, and failure modes were determined. the data were analyzed using one-way anova and fisher’s exact test (α = 0.05).results: the mean sbs values (mpa) were: group 1 = 9.37 ± 3.04, group 2 = 8.37 ± 2.86, group 3 = 7.44 ± 3.43, group 4 = 8.27 ± 3.34, and group 5 = 7.27 ± 2.65. no statistically significant differences were found in bond strength (p = 0.393) or failure mode distribution (p = 0.422) among the groups.conclusions: neither the adhesive type (etch-and-rinse versus universal) nor the application mode of universal adhesive (self-etch versus etch-and-rinse) significantly affected the repair bond strength of aged bulk-fill composites. in addition, silane application did not improve bond strength during composite repair.