Shaza M. Hammad¹, Noha A. El-Wassefy², Mohamed A. Elsayed^{3 1} Professor of Orthodontics, Faculty of Dentistry, Mansoura University, Egypt. ² Lecturer of Dental Biomaterials, Faculty of Dentistry, Mansoura University, Egypt. ³ Graduate student, Department of Orthodontics, Faculty of Dentistry, Mansoura University, Egypt. Abstract: Objectives: To evaluate the masking effectof resin infiltrant on post-orthodonticwhite spot lesions (WSLs) in comparison with other techniques (remineralization with nano-hydroxyapatite toothpaste and microabrasion) over different time intervals (0 month, 1 month, 3 months and 6 months). Methods:WSLs were artificially created on sixty human premolars enamel surface and randomly assigned to equal four groups (n=15 each): nano-HA toothpaste, Microabrasion (opalusture), resin infiltrant (Icon) treatment, or artificial saliva (control group). The color change (ΔE) of each specimen was measured by dental spectrophotometer (Vita Easyshade) at different time points: baseline, after WSLs' creation, after application of treatments, one month, three and six months after treatments application. Results: The ΔE value didn't differ significantly for the four groups at baseline measurement before treatment (p > 0.05). Icon resin infiltrant improved the color of WSLs significantly immediately after its application, giving the lowest ΔE value (3.00±0.59) when compared to other treatments (p < 0.001). There were no significant changes in ΔE for all groups during the follow up intervals (one month, three and six months) after treatments application (p > 0.05). Conclusions: Resin infiltrant can significantly mask the whitish appearance of post-orthodonticwhite spot lesions and restore the natural appearance of enamel better than nano-HA toothpaste and microabrasion.