Objective: to compare the clinical performance of newly introduced resin modified glass ionomer varnish (Clinpro™ XT) versus resin infiltration in treatment of post-orthodontic white spot lesions. Material and Methods: Six participants (70 teeth) were enrolled with post-orthodontic white spot lesions. Randomization was performed according to patient selection for the sealed envelope containing which half will receive the control (resin infiltration (ICON, DMG) and the other will receive the intervention (resin modified glass-ionomer cement varnish (Clinpro™ XT, 3M)). Follow up was done after 1 day, 1 week, 1 month, and 3 months, 6 months and 12 months. The color was assessed by spectrophotometer while the degree of demineralization was measured by Diagnodent pen 2910. Patient satisfaction was assessed using (VAS) Visual analogue scale. Results: Regarding color change, significant improvement in lightness for ICON group, while Clinpro™ XT group, the change was insignificant. The demineralization data revealed significant decrease in demineralization with resin infiltration after immediate application. Clinpro™ XT showed also significant decrease after immediate assessment and significant increase in demineralization in 6 and 12 months. Conclusion: Resin infiltration can be considered more as an alternative treatment rather than fluoride varnish. Clinpro™ XTis considered as a preventive protocol, provided that renewal application is needed after 3 months. Keywords 3M Resin cement; Resin cements; Glass ionomer cements; Fluorides; Follow up studies; Glass ionomer.