Effect of Different Aging Intervals on the Repair Shear Bond Strength of Universal Composite Repaired with Single-Step Self-Etch Adhesives: An In Vitro Experiment

AIM: To assess the shear bond strength (SBS) of repaired composites that had been aged using two thermocycling protocols and repaired using three different single-step self-etch adhesives.
MATRERIAL and METHOD: In total, ninety composite samples were prepared and assigned into two aging groups (5000 and 10000 thermocycles; n=45 each). Each group was then subdivided to (n=15) adhesives used for repair: 3M™ Single Bond Universal, GC G-Premio BOND, and CLEARFIL™ Universal Bond Quick. Repair of composite specimens were performed with the same composite. The specimens were subsequently mounted in acrylic blocks and subjected to repair SBS testing using a universal testing machine. Statistical analyses were carried out with the Kruskal–Wallis H test and the Mann–Whitney U test, with the significance level set at p<0.05.
RESULTS: At 5000 cycles, GC G-Premio BOND presented significantly lower SBS compared with 3M™ Single Bond Universal and CLEARFIL™ Universal Bond Quick (p=0.011 and p=0.003, respectively). At 10000 cycles, CLEARFIL™ Universal Bond Quick exhibited significantly higher values than 3M™ Single Bond Universal and GC G-Premio BOND (p=0.017 and p=0.007, respectively). Within-adhesive comparisons revealed significant reductions in all groups after 10000 cycles (p=0.0001, p=0.005 and p=0.0001, respectively for Subgroups 1, 2 and 3).
CONCLUSION: Artificial aging significantly reduced SBS of all adhesives. In the course of the experimental procedure, it was demonstrated that, in comparison with other systems that were tested, CLEARFIL™ Universal Bond Quick exhibited superior performance following extended ageing. Conversely, GC G-Premio BOND consistently yielded lower values. Obtained findings suggest that the choice of adhesive may influence the success of composite repairs under simulated aging conditions.