effect of enamel preparation and light curing methods on microleakage under orthodontic brackets

objectives: this study aimed to compare the microleakage beneath metallic brackets following two different methods of enamel preparation and light curing. materials and methods: a total of 120 bovine deciduous lower incisors were randomly divided into four groups of 30 teeth. the preparations were as follows: group i: acid etching + transbond xt primer + direct illumination, group ii: acid etching + transbond xt primer + transillumination, group iii: transbond xt self-etching primer + direct illumination and group iv: transbond xt self-etching primer + transillumination. dye penetration was used as the method of microleakage evaluation. sections made at the enamel-adhesive and adhesive-bracket interfaces were evaluated under a stereomicroscope. the kruskal-wallis and mann-whitney u tests were used for statistical analysis. the level of significance was set at p<0.05. results: all groups showed greater microleakage at the gingival in comparison to the incisal margin and the differences were significant among groups with transillumination (p<0.001). no significant differences were observed in the microleakage scores at the gingival and incisal margins in any of the interfaces (p>0.05). mesiodistal margins of the self-etching group with direct illumination showed significantly lower scores in comparison with acid etched group (p<0.05). conclusion: use of self-etching primers for bonding of orthodontic brackets yields acceptable results if all bracket margins are cured directly.