This was a randomized controlled clinical study, which used CBCT imaging and flapless surgical technique to place implants in partially edentulous patients and compare the accuracy of implant placement when using tooth supported computer aided surgical guides manufactured by two different techniques; additive and subtractive. All Patients were diagnosed and selected according to specific inclusion and exclusion criteria. All Preparatory procedures for implant insertion were done in a prosthetic driven approach using a vacuum template modified to be the radiographic stent constructed for imaging and planning procedures. The CBCT image was used for the virtual surgical and prosthetic planning of implant placement using the Materialise Interactive Medical Image Control System MIMICS 15.0 software.Patients were divided into two groups; the 1stgroup received additive (selective laser sintered) computer guided surgical stent. The 2ndreceived a subtractive (milled) computer guided surgical stent. On the day of surgery, surgical guides were fitted and stabilized with flowable composite material. Full sequence of surgical drilling was done through the keys of the guided kit and tapered threaded implants were placed through the surgical guide. Immediately after the surgery a second CBCT was made for each patient. At the end of the study, each patient received implants was restored at the end of the study with a fixed prosthesis. Accuracy measurements were done using Materialise Interactive Medical Image Control System MIMICS 15.0 software by superimposing the actually placed implants with the virtually placed implants. The results were tabulated and statistically analyze to reach a conclusion.