Aim: This study aimed to assess the microanalysis for remineralization potential of surface pre-reacted glass (S-PRG) restorative material versus Resin-modified glass ionomer. Subjects and methods: twenty-seven caries-free, freshly extracted, human permanent premolar teeth were used. Non-beveled trapezoidal class V cavities were performed in the gingival one-third of the buccal surface. The teeth were separated into three equal groups (nine=9). Group (1) was used as a negative control without any restorations. Group (2) was restored with S-PRG filler (Giomer; Beautifil II), and Group (3) was restored with RMGI (Fuji II LC). All restored teeth were cut buccolingually into two sections in a vertical plane parallel to the tooth’s long axis. Remineralization of the tooth structure (calcium, phosphorus, and fluoride) was assessed by SEM/ (EDX) after one day, 1 month, 3 months, and 6 months, respectively.