Statement of the Problem:The bone particles collected during osteotomy could be used as autogenous bone graft materials for dental implant surgery. Different factors such as drill design may influence its clinical viability.Purpose:This study examined the effect of drill design on the osteoblast viability and histopathology parameters of bone collected during the preparation of dental implant site.Materials and Method:In this experimental study, 90 samples were obtained from three different bone drilling systems including Bego, Implantium, and Dio during fixture installation in patients requiring treatment at the Department of Periodontology, Dentistry University Hamedan. The MTT (3-4,5-Dimethylthiazol2,5-diphenyltetrazolium bromide) was used to determine percentage of cell viability. Samples were fixed in 10% formaldehyde for histological evaluation. Then, they were kept in 10% EDTA solution for 4 weeks for decalcification. The provided slides were evaluated regarding bone structure and osteocytes counts for assessment of viability. Tukey test and SPPS 21 software were used for statistical analysis.Results:The result showed the viability of osteoblast obtained by Dio (0.45±0.04) was significantly better than Bego (0.37±0.05) and Implantium (0.37±0.04) systems. In histopathological evaluation, the grafting material obtained by Dio presented the best osteoblast morphology.Conclusion:It might be concluded that drill geometry has significantly influenced the viability of bone particles collected during the preparation of implant sites .Moreover, characteristic geometry alone cannot represent the performance of a particular drill, and several geometric features should be concerned. The results of this study showed that the geometry of the Dio drill was the best considering the viability and histopathological evaluations.