The purpose of this study was to analyze the incidence and risk factors of possible inferior alveolar nerve (IAN) injury after extraction of the mandibular third molars. A total of 6182 patients were examined for 10,310 mandibular third molar teeth. Panoramic radiography and patients’ medical records were used to analyze age, gender, and impaction pattern of the mandibular third molar. Cone beam computed tomography (CBCT) was used to investigate the detailed pathway of the inferior alveolar nerve and evaluated the presence of symptoms of nerve damage after tooth extraction. In CBCT, 6283 cases (61%) of the inferior alveolar nerve were actually in contact with the root of the mandibular third molar. The correlation with the panoramic signs of root darkening (p < 0.001), root deflection (p < 0.001), interruption of the IAN (p < 0.001), diversion of the IAN (p < 0.001), and narrowing of the IAN (p < 0.001) had statistical significance. Of the 4708 patients who underwent surgical extraction, 31 (0.658%) complained of nerve damage. Among them, 30 patients (0.637%) complained of symptoms of inferior alveolar nerve damage, and 1 patient (0.02%) complained of symptoms of lingual nerve damage. There was a significant correlation with IAN injury in cases where the roots became dark at the IAN area (p = 0.018) and there was diversion of the IAN at the root area (p = 0.041). When the narrowing of the IAN and the lingual driving pathway of the inferior alveolar nerve appeared simultaneously in CBCT, the risk of IAN injury was high.

With the improvement in computer graphics and sensors, technologies like virtual reality (VR) and augmented reality (AR) have created new possibilities for developing diagnostic and surgical techniques in the field of surgery. VR and AR are the latest technological modalities that have been integrated into clinical practice and medical education, and are rapidly emerging as powerful tools in the field of maxillofacial surgery. In this report, we describe a case of total maxillectomy and orbital floor reconstruction in a patient with malignant fibrous histiocytoma of the maxilla, with preoperative planning via VR simulation and AR-guided surgery. Future developments in VR and AR technologies will increase their utility and effectiveness in the field of surgery.

The aim of this study is to compare the implant placement deviations and evaluate the 1-year post-implant placement bone loss of pilot and fully guided implant placement protocols. In the first method, the pilot drill is used for guide surgery, and the following procedure is a method for performing implant surgery in a non-guided protocol. The second method is to perform fully guided surgery. A total of 74 implants in 20 patients were included. Postoperative CT scans were used to compare the implant placement deviations with the preoperative plan. In addition, bone loss was compared one year after surgery. In shoulder area, the implant deviations from the planned positions for dx(mesio-distal), dy(bucco-lingual), dz(vertical) dimensions, mean deviations with pilot-guided protocol (n = 31) were 0.50 ± 0.42 mm, 0.61 ± 0.55 mm, 0.87 ± 0.71 mm, and 1.33 ± 0.75 mm, respectively. The corresponding deviations for fully guided protocol (n = 41) were 0.50 ± 0.52 mm, 0.29 ± 0.27 mm, 0.56 ± 0.51 mm, and 0.96 ± 0.57 mm. In apical area, the corresponding deviations for pilot-guided protocol were 0.75 ± 0.72 mm, 0.61 ± 0.46 mm, 0.98 ± 0.76 mm, and 1.54 ± 0.87 mm. Deviations for fully guided protocol were 0.91 ± 0.90 mm, 0.44 ± 0.39 mm, 0.54 ± 0.51 mm, and 1.38 ± 0.76 mm, respectively. Angular deviations were 3.33 ± 3.23° with pilot-guided protocol and 3.90 ± 1.85° with fully guided protocol. The average bone loss after 1 year was 0.50 + 0.29 mm and 0.50 ± 0.24 mm, respectively. In the shoulder area, dy(bucco-lingual) of horizontal deviations, vertical deviations, and mean value of the deviations showed a statistically significant difference between fully guided and pilot-guided (p = 0.005, p = 0.033, and p = 0.023, respectively). In the apical area, vertical deviations showed a statistically significant difference. However, the mean value of the deviations did not show a statistically significant difference (p = 0.347). There was no statistically significant difference in angular deviations (p = 0.59).