Objectives:  This study was conducted to evaluate the remineralizing effect of casein phosphopeptides -amorphous calcium phosphates (CPP-ACP) and tricalcium silicate using scanning electron microscope (SEM) ,Energy dispersive Xray (EDX) and  laser induced fluorescence device(Diagnodent). Materials and methods:  Thirty sound human maxillary incisors (n=30) that were extracted due to periodontal diseases and collected from Oral Surgery clinic at Faculty of Dentistry, Mansoura University, according to the regulation of the ethics committee The teeth were randomly divided into three groups (n=10) ; Group A: control group,Group B:CPP- ACP group and Group C :Tricalcium silicate group with 10 samples in each group(n=10). The specimens of control group were cut into two halves, one of them was used as  negative sound control and the other section was subjected to demineralization process. All specimens of other remaining groups were subjected to the demineralization process, then subdivided into two subgroups by cutting the tooth longitudinally through the center of the tooth by carborundum bur. One half was left without any surface treatment, act as positive control group and the other  received remineralizing  treatment  (test group). All specimens  were measured by laser induced  fluorescence device(Diagnodent pen, KAVO model 2095, Biberach, Germany) and prepared for elemental and morphological analysis by drying to ensure that the teeth moisture free. The tested groups were  tested after 3 months,6months and 9months.They stored in artificial saliva that prepared in faculty of pharmacy Mansoura university