Objective To summarize the use of the CT-guided mandibular angle plastic osteotomy.Methods The clinical data of mandibular angle plastic osteotomy were analyzed under the CT navigation in recent 3 years in our department.Thin-slice CT scans of the mandibular angle were performed before the operation.The CT data were input to the system of neuronavigation.The surgical procedures were then taken under the CT navigation.Results All of patients who received this new technology obtained good plastic effects and safe operation.The anatomic location accurately achieched with short operation time and less bleeding during the operation and distinct curative effect and fast recovery after operation.The effects of the treatment were fine.No visible complications occurred.Conclusions The CT navigation could fix accurately on position of important blood vessels and nerves which could be injured accidentally during operation and,of course,the safety of the operation is improved.The CT navigation can also determine the position and quantities of osteotomy from three dimensional angles,reduce effectively the surgical complications and the risk of surgery,reduce the psychological burden of patients efficiently and increase their confidence and credibility to the operation and surgeons.

Objective This paper aims to investigate the application of intraoral scanning and cone beam computed tomography(CBCT)registration implant robot in dental implant surgery.Methods The data of 40 cases with dental de-fect of robot-assisted implantation from November 2023 to May 2024 were retrospectively analyzed.Before the opera-tion,the intraoral scan data and CBCT data of the posi-tioning markers were automatically fused with the initial CBCT images,and the registration error was calculated.The average registration error of positioning markers was determined during the operation,and the implantation ac-curacy was analyzed after the operation.Results The intraoral scan data and CBCT data of 40 patients with dental defect wearing positioning markers were successfully registered with the initial CBCT image,and the registration errors were(0.157±0.026)mm and(0.154±0.033)mm,respectively.Statistical analysis showed no statistical significance between them.The registration errors of the marker was(0.037 3±0.003 6)mm.A total of 55 implants were performed,and the total deviations of the implant point and the apical point were(0.78±0.41)and(0.89±0.28)mm,respectively.The transverse deviations of the implant point and the apical point were(0.44±0.36)and(0.58±0.25)mm,respectively.The depth deviations of the implant point and the apical point were(0.51±0.32)and(0.54±0.36)mm,respectively.The devia-tion of the implant angle was 1.24°±0.67°.Conclusion The fusion technology based on intraoral scanning and CBCT registration can meet the accuracy requirements of preoperative registration of oral implant robots.The technology in-creases the choice of registration methods before robot-assisted dental implant surgery and reduces the multiple radiation exposuresof the patient.