Effect of Different Bonding Systems on Shear Bond Strength of Buccal Tubes Bonded to Various Restorative Materials: An In Vitro Study
Introduction: Orthodontic bonding to restorative surfaces poses a clinical dilemma as it does not follow a single universally accepted procedure. Aims: This study aimed at evaluating shear bond strength (SBS) and adhesive remnant index (ARI) of buccal tubes bonded to different restorative surfaces using three bonding systems. Materials and Methods: The sample included 54 restorative surfaces divided into three groups consisting of amalgam, composite and feldspathic porcelain (n=18), randomly divided into three bonding subgroups: A, B and C (n=6). In subgroup A, conventional bonding was conducted using Transbond XTTM. In subgroups B and C, Assure Plus® and ScotchbondTM were used, respectively. Six human molars were bonded with standard acid-etching technique and served as control. All specimens were thermo cycled 5000 times between 5°C and 55°C before SBS testing. Bond failure sites were classified using the ARI system. The results were statistically analyzed using one-way analysis of variance (ANOVA) and Kruskal-Wallis tests (P ≤ 0.05). Results: For all bonding systems used, SBS values were significantly lower on both amalgam and porcelain than enamel, while no significant difference was found between composite and enamel. ARI scores showed no significant difference among the bonding systems within each restorative group. Conclusion: The three bonding systems tested have produced SBS values above the clinically appropriate level in all restorative groups. Scotch bond created clinically acceptable SBS with no need for additional primer, and relatively low risk of surface fracture upon debonding. Therefore, it might be helpful in orthodontic bonding to the restorative surfaces tested in this study.