In vitro and in vivo comparison of orthodontic indirect bonding resins: A prospective study

The aim of this study was to evaluate in vitro shear bond strength (SBS) and in vivo bond survival rates of brackets bonded using orthodontic indirect bonding resins.

For the in vitro study, the first group was direct bonding control group. In Groups II and III, bonding was performed with indirect bonding resins that were either chemically or light-cured. The SBS of each sample was examined. For the in vivo study, full-mouth brackets were placed in 20 patients using a split-mouth approach, with either chemically-cured or a light-cured indirect bonding resin. The patients were followed for 12 months. Data were statistically evaluated using analysis of variance, Tukey's tests, and Weibull survival analysis.

The mean SBS values (MPa) were 17.6 ± 6.6, 13.1 ± 4.7, and 15.1 ± 5.9 for Group I, Groups II, and III, respectively, (P < 0.05). The adhesive remnant index scores of the groups were generally Score 3 and Score 4. In vivo follow-up showed no statistically significant differences in total bond failure rate between groups (P > 0.05).

In vitro study showed lower SBS with chemically-cured indirect bonding resin than flowable light-cured resin and the control group, but in vivo failure rates of both indirect resins were found to be adequate for clinical usage.