This study was conducted to evaluate and compare the efficacy of composite releasing ca and po4 ions versus conventional glass ionome and resin-modified glass ionomer regarding,: remineralization capacity and micro leakage in permanent premolars ( in vitro study).A total number of 34 teeth. According to the circumstances of this study, it was concluded that Tetra calcium phosphate composite are more effective against microleakage and further decaythan other restorations by enhance remineralization capacity.