Bond strength of repaired anterior composite resins: an in vitro study

The objectives of this study were to investigate the repair potential of two commercially available composite resins in terms of bond strength, and the effectiveness of two commercially available adhesive systems used as intermediary materials in the repaired specimens. The repair strength of Helio Progress (HP) and Herculite XRV (XRV) was tested using two bonding agents: DenTASTIC (DT) and All Bond 2 (AB2). The effect of surface abrasion of specimens and the effect of time on repair strength were also investigated. Surface abrasion significantly improved the bond strength (P < 0.001) and the use of bonding agents further enhanced bond strength but not significantly. Use of bonding agents alone improved the repair bond strength significantly (P < 0.001). Repair of HP with HP after surface abrasion and application of DT produced the highest repair bond strength which was 99% of the cohesive strength of the control (unrepaired) specimens. Although there were some differences in the bond strength over the time period of the study (one month) none of these was statistically significant. It is concluded that surface abrasion coupled with the application of bonding agent produces the highest repair strength. It seems likely that clinically acceptable bond strengths are possible after repair of anterior composite resins.