Objective: This study was designed to compare the relative efficiency of GC, Tooth Mousse, which contains 10% ACP-CPP and GC Tooth Mousse Plus which contains amorphous calcium phosphate casein phosphopeptide (ACP-CPP) with sodium fluoride 0.2% w/w (900 ppm) to inhibit enamel demineralization adjacent to orthodontic brackets in vitro. Materials and methods: Forty-five non-carious, human maxillary premolars with no visible enamel defects were collected and bonded with stainless pre-adjusted stainless steel premolar brackets with light-cure composite resin. The teeth were randomly assigned into three groups of 15 teeth and each group coded with unique colored nail varnish leaving a rectangular window extending occlusally. The teeth in each group were immer sed separately in an artificial saliva solution for 11 hours and an acid solution for 1 hour maintained at room temperature. Group I, control group did not receive any application, as Groups II and III received GC Tooth Mousse and GC Tooth Mousse Plus respectively. The teeth were immersed alternately in the saliva and acid solution for 31 days. Two sections, each approximately 0.5 mm thick were obtained from each specimen. The sections were photographed with a polarized light microscope at 4× magnification. The depths of demineralized enamel in each section were measured at three sites. Results: The results of this study showed that GC Tooth Mousse Plus on daily application will provide maximum protection against the enamel demineralization in orthodontic patients, by reducing the lesion formation and simultaneously remineralizing the demineralized area by providing calcium phosphate ions and fluoride ions constantly. Conclusion: GC Tooth Mousse Plus (ACP-CPPF) showed better efficiency in reducing the demineralization and enhancing the remineralization around the orthodontic brackets and have maximum benefit compared to GC Tooth Mousse with good patient compliance.