Effect of Self-etchant pH on Shear Bond Strength of Orthodontic Brackets: An in vitro Study

Abstract

ABSTRACT Aims To determine the effect of self-etchant pH on shear bond strength of orthodontic brackets; to compare the shear bond strengths of brackets bonded with three SEPs and brackets bonded with conventional etch, rinse, bond method and to find the brackets/adhesive failure mode. Materials and methods One hundred and twenty premolar teeth were cleaned, mounted, and randomly divided into four groups of 30 samples each- Transbond XT conventional etch and bond system (control), Adper SE Plus SEP (3M ESPE) with a pH of 0.9 to 1.0, Transbond Plus SEP (3M Unitek) with a pH of about 1.0 and Clearfil SE Bond SEP (Kuraray America) with a pH of around 2.0. All teeth were bonded with Transbond XT paste (3M Unitek). The teeth were debonded within half an hour after initial bonding by using a universal testing machine. The residual adhesive on each tooth was evaluated. ANOVA was used to compare the shear bond strength (SBS) of the three groups, and the Chi-square test was used to compare the adhesive remnant index (ARI) scores for the three groups. Results ANOVA indicated significant differences between the groups. Clearfil attained the SBS (6.5 ± 0.6689 MPa) closest to the control group, whereas Adper inspite of being the most aggressive recorded the lowest SBS (5.7 ± 0.5695 MPa). Transbond self-etching primer achieved a mean SBS of 6.1 ± 0.6211 MPa. However, all the three SEPs recorded SBS which was significantly less than that of Transbond conventional etch, rinse and bond system (11.8027 ± 0.8059 MPa). The comparisons of the ARI scores between the three groups indicated that bracket failure mode was significantly different between the three groups (p < 0.05). Conclusion These findings show that factors other than pH, such as the ability of the bonding adhesive to form a chemical bond to enamel and the strength of the bonding adhesive itself, significantly influence the SBS of orthodontic brackets. How to cite this article Goyal A, Jyothikiran H, Shivalinga BM. Effect of Self-etchant pH on Shear Bond Strength of Orthodontic Brackets: An in vitro Study. World J Dent 2012;3(1):41-49.