The present study was carried out on fourteen completely edentulous patients, who received two types of implant supported prostheses, the screw retained type and the removable telescopic overdenture.Every patient received four inter-foraminal implants regarding the mandibular arch and four anterior implants for the maxillary arch,computer guided surgical guides were planned for the insertion of the implants accurately with a flapless technique.Cone Beam Computed Tomography (CBCT)were made preoperatively and immediately after implant Insertion to assess the location of the implants in the planned sites.Panoramic radiographs were made immediately, six monthsand twelve months after the prostheses` use proportional area and vertical measurements were applied to determine changes in bone height of the posterior mandibular edentulous area.After twelve months, a statistically non-significant amount of bone resorption was reported for both the groups.