Effects of application mode of self-etching primer on shear bond strength of orthodontic brackets

Abstract

ObjectivesTo compare the effects of application mode of one self-etching adhesive on the shear bond strength of metallic orthodontic brackets. MethodsSeventy-five healthy bovine incisors were divided into 5 groups (n=15). The self-etching primer (Transbond Plus, 3M Unitek) was applied on the enamel actively and passive for 0 (control), 5 and 10s, followed by air jet application and light cured for 10s (600mW/cm2). The metal brackets were bonded with adhesive (Transbond XT) and light cured for 20s each proximal surface (mesial and distal). The shear bond strength was determined after water storage at 37°C for 24h. The specimens were tested using a universal testing machine (Instron 3342). Once debonded, each specimen was examined to identify the failure mode. The bond strength data were subjected to One-way Anova and Tukey tests (α=0.05) and failure mode data were analyzed by Kruskal–Wallis test (α=0.05). ResultsNo significant difference in bond strength was found between 5 groups. Increasing the application time and applying agitation of self-etching primers did not affect the shear bond strength (p=0.487). There were no differences between failure mode values in all tested groups (p=0.88) and score 1 was predominant. ConclusionsThe shear bond strength of the self-etching adhesive is not influenced by the application mode.