Background: The primary purpose of this study is to determine the effect of Caries resin Infiltrant (Icon) on theshearbond strength ofmetal orthodontic brackets using three adhesive systems. Materials and methods: Sixty-six extracted sound upper first premolars tooth were selected. The collected teeth were divided equally into three groups: Grengloo, (Italy), Light bond, (USA) and Enlight(Italy).Each one contains twenty-two teeth, which were bonded using the bonding adhesive. Half of them were manipulated with ICON and half of them without ICON. Statistical analysis was performed including t-test, ANOVA test and Tukey's HSD test. Result: After comparison among all groups with ICON, all groups (Grengloo vs. Light bond, Grengloo vs. Enlight & Light bond vs. Enlight) had a significant difference. After comparison among all groups without ICON, two of them had a significant difference which was (Grengloo vs. Light bond & Light bond vs. Enlight) while the other group (Grengloo vs. Enlight) showed anon-significant difference. Conclusion: The application of the caries infiltrant following 37% phosphoric acid etching on sound enamel prior to orthodontic bonding could be an alternative to be used as an additional preventive measure against WSL formation. It was concluded that the surface infiltrated by Icon (DMG) did not interfere negatively on the bond strength to the resin composite.
