Effect of prophylactic pastes containing active ingredients on the enamel-bracket bond strength of etch-and-rinse and self-etching systems

Objective: To evaluate the effect of prophylactic pastes containing active ingredients such as amorphous calcium phosphate (ACP), fluoride, or a combination of both on the enamel-bracket tensile bond strength. Materials and Methods: Human molars were randomly divided into four groups (N = 40) according to the type of prophylactic pastes: control. (no active ingredients), paste containing fluoride, paste containing ACP, and paste containing both fluoride and ACP. After prophylaxis, 20 brackets per group were bonded using an etch-and-rinse bonding technique (37% phosphoric acid and Ortho solo), and the other remaining 20 brackets were bonded using a self-etch bonding technique (Clearfil S(3)Bond). Samples were tested for tensile strength 24 hours after bonding using a universal testing machine. Data were analyzed using analysis of variance (ANOVA) and Student's t-test with significance level at .05. Results: The mean tensile bond strength varied between 3.043 (ACP) and 9.232 (control) MPa. The etch-and-rinse bonding technique was significantly affected by pastes containing active ingredients (P <.001). The self-etching system was not significantly affected by different pastes (P >.05). Conclusions: Cleaning enamel surfaces with prophylactic pastes that contain ACP and/or fluoride, prior to orthodontic bonding, resulted in a statistically significant decrease in the tensile bond strength of etch-and-rinse bonding technique. (Angle Orthod. 2011;81:788-793.)