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.

VR and AR technology have gradually developed to the extent that they could help operators in the surgical field. In this study, we present a case of VR simulation for preoperative planning and AR navigation applied to orthognathic surgery. The average difference between the preplanned data and the post-operative results was 3.00 mm, on average, and the standard deviation was 1.44 mm. VR simulation could provide great advantages for 3D medical simulations, with accurate manipulation and immersiveness. AR navigation has great potential in medical application; its advantages include displaying real time augmented 3D models of patients. Moreover, it is easily applied in the surgical field, without complicated 3D simulations or 3D-printed surgical guides.

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 purpose of this study is to analyze the clinical results of the implant rehabilitation for a jaw reconstructed by the deep circumflex iliac artery (DCIA) flap. A total of 13 patients were included in this study from 2010 to 2020. Medical records were collected retrospectively and analyzed. The mandible was involved in 10 cases and the maxilla was in 3 cases. The average width of the DCIA flap was 8.6 mm, and the height was 20.65 mm. A total of 41 dental implants with a diameter of 3.9–5.0 mm and a length of 10.0–11.5 mm were placed at an average of 12.3 months after the reconstruction. The average follow-up period after delivering a permanent prosthesis was 15 months (range, 2 to 51 months) and the overall mean follow-up period was 48 months. In all, 3 implants of the total 41 implants were removed. The DCIA flap is the most suitable for reproducing the original contour of the original jawbone compared with the fibular flap. In addition, the height and width of the reconstructed bone is appropriate for implant placement, which is advantageous for the rehabilitation of oral function and aesthetics using the implant.

Resection of malignant lesions in the oral and maxillofacial area causes functional and morphological defects. In order to recover from these defects, reconstruction surgery is needed, such as a primary closure or a flap. There are advantages and disadvantages to the method of using the primary closure and the flap, and the choice of procedure is entirely up to the surgeon. The purpose of this study is to evaluate the availability of primary closure in patients. For 10 years, from January 2010 to May 2020, patients who recovered using flaps after removing malignant lesions from the oral cavity and those who closed the lesion using primary closure were investigated. The investigation was conducted by searching the database of the hospital. There were 85 patients who removed malignant lesions in the oral and maxillofacial area, and among them, 16 patients closed the soft tissue defects using primary closure. Operation time, histologic types, stages, wound status, and period of hospitalization according to the patient’s medical records were investigated retrospectively. Between the staging and the primary closure, statistically significant differences were observed between stage I and stage II patients in 13 patients using the primary closure. (p = 0.046). Statistically significant differences were identified between operation time and primary closure, with an average of 4.02 h (p = 0.015). The average period of hospitality for patients who underwent primary closure was 13.4 days, compared to 26.7 days for those who underwent flap surgery. This difference was statistically significant (p = 0.0003). As a result of three-way ANOVA analysis on operation time and hospital stay, only neck incision, reconstruction method (flap or primary suture), and intrastage reconstruction method had a statistically significant effect on operation time and period of hospitality. This study evaluated the use of primary closure in patients who underwent resection of malignant lesions in the oral and maxillofacial area. Although the majority of patients underwent reconstruction with flaps, our results showed that primary closure could be a viable option for certain patients with early-stage lesions.

Jaw defects can have a variety of causes, including tumors, trauma, and osteomyelitis. The reconstruction of jaw defects has been improved with the free flap technique and sophisticated microvascular techniques. A deep circumflex iliac artery (DCIA) flap provides a large amount of bone for the reconstruction of the mandible. However, various complications and side effects, such as abnormal hip contour, hernia, severe bleeding tendency, gait disturbance, and hypoesthesia, can occur. Iliac bone fracture is not a common complication after DCIA flap harvesting, because the anterior superior iliac spine (ASIS) can include the harvested flap. If an iliac avulsion fracture occurs, various treatment options exist. If severe dislocation of the bone fragment exists, open reduction and internal fixation are required. At this time, orthopedic implants composed of various materials can be used. Among these, when using a 3D-fabricated implant using a Ti₆Al₄V alloy, the accuracy of the size and shape is excellent, and it can have mechanical–biocompatible advantages. In this study, we report cases of iliac bone fracture after reconstruction of the jaw with a DCIA flap and the treatment modality using a 3D-printed, patient-specific titanium implant.