Rebonding of Composite Resin With Current Adhesives

“Rebonding” composite resin to itself, after elimination of the oxygen-inhibited layer, eases correction of restorations. Use of bonding resins achieves optimal results.  Traditionally, phosphoric acid cleansed the “freshened” restoration surface but with new bonding products, this may not be necessary. Objective:  This work compared several self-etching and traditional materials, with and without etch treatment, at 24 h and with the “best” 24 h technique (B) at 15 m after placement. Method: Flat discs of composite resin (TPH) were wet machined through 320 grit silicon carbide abrasive after 24 h in artificial saliva and immediately after fabrication.  All Bond 2 (AB), Tyrian – One Step (TO), i-Bond (IB), Simplicity Adhesive (SA), L-Pop (LP), PQ-1 (PQ), and Tenure Uni-Bond (UB) were used to bond cylinders of composite resin (TPH), following manufacturers’ directions, to discs with (W), without (N) etch treatment, and with B technique. After storage at 37°C for 24 h, the specimens were tested to shear mode failure. Ten specimens composed a cohort. Cohort mean shear bond strengths, in Megapascals with standard deviations, were determined and statistical analysis was by ANOVA and Tukey-Kramer HSD at 95% confidence. Results: Except for SA and UB, differences in bond strengths (p < 0.05) were found among treatments, usually favoring manufacturers’ recommendations. SA was strongest and LP was weakest in all rebonding (p < 0.05).Conclusion: Except for LP, all bonding agents can be used for rebonding composite resin, though SA was best.