The aim of this study will be to evaluate the shear bond strength of metallic and ceramic orthodontic brackets with different modifying bonding protocol. Sixty lower incisors will be selected with similar anatomy and divided in 6 groups of 10 teeth each. In the groups I, II and III metallic brackets will be used and in the groups IV, V and VI ceramic brackets. In groups I and III, brackets will be bonded according to manufacturer's instructions. In group II and IV, primer will be applied in the tooth, adhesive on basis of the bracket with a one step light cure. In the groups III and VI primer will be applied in the tooth and on the basis of the bracket, follow by the adhesive on the bracket and also an one step light cure. The same orthodontic adhesive will be used for all groups. Cement thickness will be standardized with the use of a heavier Gilmore needle. After 24 hours, the specimens will be attached to a loop wire and submitted to a shear force under a load cell of 500Kgf. After testing the shear bond strength, the bracket bases and the enamel surfaces will be examined to evaluate and quantify the amount of adhesive remaining on the teeth. One-way Anova or more and Tukey tests will be performed to compare the groups.
News published in Agência FAPESP Newsletter about the scholarship: