Objective: To evaluate the effect of two different prophylaxis protocols on the friction force in sliding mechanics during in vivo leveling and alignment. Materials and Methods: The sample comprised 48 hemi-arches divided into three groups according to the prophylactic protocol adopted. Group 1 consisted of patients undergoing prophylaxis with sodium bicarbonate, group 2 consisted of patients submitted to prophylaxis with glycine, and group 3 consisted of patients without prophylaxis, as a control. All patients received hygiene instructions and, with the exception of group 3, prophylaxis was performed monthly. After 10 months, the brackets were removed from the oral cavity and submitted to friction force tests and qualitative analysis by scanning electron microscopy. Analysis of variance followed by Tukey tests was performed for intergroup comparison regarding the friction force. Results: The experimental groups presented significantly smaller friction forces than the group without prophylaxis. Accordingly, qualitative analysis showed greater debris accumulation in the group without the prophylactic procedures. Conclusions: Prophylactic blasting with sodium bicarbonate or glycine can significantly prevent an increase of the friction force during sliding mechanics.