This study was conducted to evaluate the effect of using the thermo-plastic acrylic denture base versus using the conventional acrylic denture base on the supporting structures in implant retained mandibular overdenture.Twelve completely edentulous male patients were included in the study.They were divided in to two groups, group A ( experimental group) and group B ( control group)Group A: Six patients were included, each patient had a Mandibular implant retained over-dentures using thermo-plastic acrylic denture base (Versacryl). Group B: Six Patients were included, each patient had aMandibular implant retained over-dentures using conventional acrylic denture base.Patient’s satisfaction and radiographic evaluations were carried out for every patient at 3, 6 and 9 months of the functional loading.Assessment of the patient’s satisfaction was performed using a questionnaire with score measurement. The questionnaire showed that there was a significant increase in patient’s satisfaction in experimental group, than the control group. (p< 0.05).Assessment of the periimplant bone loss was performed by direct digital radiography (DDR) using Digora computerized system. The radiographic assessment showed at 3,6and 9months it was found that the peri-implant bone loss in experimental group was significantly lower than the conventional group.