Khloud E.M.*,Radwa M. K. Emera**, Habib A. *** and Ahmed W. **** ^{*Clinical Demonstrator of removable Prosthodontics, Faculty of Dentistry, Mansoura University, Egypt. ** Associate Professor of Removable Prosthodontics, Faculty of Dentistry, Mansoura University, Egypt. *** Professor of removable Prosthodontics Faculty of Dentistry, Mansoura University, Egypt. **** Associate Professor of Oral Surgery, Faculty of Dentistry, Mansoura University, Egypt}. Abstract: Purpose: this study aimed to compare the effect of the two implants position (lateral incisors and canine areas) to retain mandibular complete overdenture on the ridge base contact relation after different intervals of overdenture insertion Materials and methods: tencompletely edentulous patients were selected from theclinic of Removable Prosthodontics Department, Faculty of Dentistry, Mansoura University. According to the position of implant placement, patients wererandomly classified into 2 equal groups; group I where two implants were placed in thelateral incisors area and group II where two implants were placed in the canines' area. Positioner attachment was connected to the implant fixture to retain the mandibular implant overdenture. Periodic monitoring of ridge base contact relation was carried out at time of insertion (T0) and6 months (T6) after insertionby using CBCT (the dual scan technique procedures) .Results: There were statistically insignificant differences between the two groups (lateral incisors position group and canines' position group) regarding the ridge base contact relationship. Conclusion: Within the limitations of this study (patient number and study period), the ridge base relationship of two implant retained mandibular overdenture is maintained regardless to the implant position Key words: mandibular overdenture, implant position, ridge base relation.