Evaluation of tensile strength of brackets bonded by indirect technique

André TARTAMANO, Fábio NAUFF, Sandra Regina Frazatto NACCARATO, Júlio Wilson VIGORITO

Aim: The purpose of this study was to evaluate the bonding strength of brackets for direct and indirect bonding techniques. Methods: Were used 50 human premolars recently extracted for orthodontic reasons. These teeth were divided in 5 groups and metalic orthodontic brackets (Abzil-Brazil) were bonded by direct and indirect techniques with orthodontic composite resins: group I (Control I) - direct bonding using Concise (3M-Unitek-EUA); group II (Control II) - direct bonding using Transbond (3M-Unitek-EUA) with XT bond system; group III - indirect bonding using Concise (3M-Unitek-EUA); group IV - indirect bonding using Transbond (3M-Unitek-EUA) with XT bonding system; group V - indirect bonding using Transbond with Sondhi bonding system (3M-Unitek-EUA). The Sondhi bonding system was designed specifically for indirect bonding. In the direct bonding technique brackets were placed directly on the enamel surface, in the indirect technique brackets were first bonded in a cast of the teeth and then they were transfered by means of a tray to the teeth. The samples were submitted to tensile tests (Instron 4400) and the statistical ANOVA and Tukey ( 1%) tests were applied. Results: The groups III and V showed lower bond strength than control groups (I and II), there was no significant difference between group IV and control groups (I and II). Conclusion: It was concluded that for indirect bonding technique only the Transbond XT (3M) didn’t show significant statistical difference when compared to the direct bonding technique.

Keywords: Orthodontics. Indirect bonding. Bond strength.

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