Background. Nowadays there are many ideas to achieve High success and reliable treatment surgeries for bothpartially and totally edentulous patient. The aim of this review to compare accuracy and advantages of computer guided navigation system vs conventional free hand method. Methods. This review has been done by searching in electronic data bases including PubMed and scopus with these key words” computer assisted surgery” , “ navigation implant surgery” , “ dynamic navigation implant” , “ static navigation implant” . Results. In navigation surgery for dental implants the two approaches; dynamic and static were introduced. The static navigation refers to use of surgical templates for the bone implant drilling. Dynamic navigation is used to monitoring through a three_dimentional softwar of the bone drilling and implant placment following the preoperative plane, while the freehand implant placement requires no guided stents. Through computer guided surgery it possible to reduce deviation and differences between the preoprative CBCT images and measurements from final treatment outcome. Also, the CAS method is usefull in cases with complications like proximity of inferior alveolar nerve. Conclusions. A number of statistically singnificant were found in comprison. In computer assisted group indicate no implant fails, reduce of post surgical pain and swelling. And the mean marginal bone loss decreased.

Background: In resent years, crime rate has been increased. The aim of this study was to evaluate the computer assisted hand tracing overlay method for bite mark analysis.Methods: Impressions of both, maxillary as well as mandibular arches of 50 consenting volunteers were taken and dentition casts were prepared. Tracing by hand was manually done, and computer assisted overlay comparison was carried out.Results: Out of 2500 cross matches, expected result should have been 50 true positives and 2450 true negatives. In our study there were 38 true positive, 2406 true negatives, 44 false positive and 12 false negative matches in maxillary comparison, 44 true positive, 2424 true negatives, 26 false positive and 6 false negative matches in mandibular comparison and 31 true positive, 2446 true negatives, 4 false positive and 19 false negative matches when complete dentition (maxillary and mandibular) comparison was done. Hence this method showed significantly high false positive and true negative cases.Conclusion: We conclude that this computer assisted hand tracing overlay method for bite mark analysis helps in arriving at an exclusion rather than inclusion type of identification, owing to its high true negative cases.