OBJECTIVE: To propose a new protocol for personalized mandibular reconstruction assisted by three-dimensional (3D) retrieval model based on fully connected neural network (FCNN) and a database of mandibles, and to verify clinical feasibility of the protocol. METHODS: A database of mandibles of 300 normal northern Chinese Han people was established. On the basis of cephalometry, the mandible landmarks with good stability were further screened. Mandibular landmarks were selected and geometric features of the mandible were extracted. A 3D retrieval algorithm was developed, which could retrieve the mandible most similar to a given mandible from the database. A FCNN was built to train the algorithm to improve accuracy of the 3D retrieval model. Using Geomagic Control 2014 software, matching accuracy of the 3D retrieval model was based on aforementioned mandible database and algorithm. From December 2019 to March 2021, a total of 5 patients underwent personalized mandibular reconstruction assisted by a 3D retrieval model based on mandible database and FCNN in the Department of Oral and Maxillofacial Surgery, Peking University School and Hospital of Stomatology. The most similar mandible was retrieved from mandible database through 3D retrieval algorithm. It was used to restore the premorbid morphology of defect area and guide mandibular reconstruction. For the 5 patients, mandible was reconstructed with iliac flap. Virtual surgical plan was transformed using individual surgical guides. RESULTS: Through screening, mandibular landmarks with high reproducibility and stability were identified and composed of mandibular landmarker protocols. After training, the average deviation between most similar mandible retrieved from the 300-case mandible database through 3D retrieval model based on FCNN and given mandible was (1.77±0.44) mm. And the root-mean-square deviation between the most similar mandible retrieved from the database and given mandible was (2.58±0.86) mm. The mandibular reconstruction surgery was successful in all the 5 patients. Their facial symmetry and occlusion were restored. All the patients were satisfied with postoperative appearance. The mean deviation between postoperative mandible and preoperative design was (0.98±0.17) mm. The area with a deviation ≤1 mm accounted for 61.34%±14. 13%, ≤2 mm accounted for 83.82%±7.35%, and ≤3 mm accounted for 93.94%± 2.87%. CONCLUSION The personalized mandibular reconstruction assisted by 3D retrieval model based on the 300-case mandible database and FCNN is feasible clinically.
Humans ; Neural Networks, Computer ; Mandibular Reconstruction/methods* ; Mandible/diagnostic imaging* ; Imaging, Three-Dimensional/methods* ; Adult ; Databases, Factual ; Female ; Male ; Algorithms ; Middle Aged ; Cephalometry

OBJECTIVE: To establish a three-dimensional finite element model of a digital wire loop space maintainer for the mandible and primary tooth loss, in order to investigate the stress, deformation, and shear force experienced by patients with the loss of the second primary molar when wearing the wire loop space maintainer. METHODS: Cone beam computed tomography (CBCT) scans were performed on the patients to create a digital model of the mandible with the absence of the second primary molar using Mimics 21.0 software. A digital model integrating the crown's retention and the wire loop structure of the full crown and ring wire loop space maintainer was constructed using pediatric space maintainer design software, utilizing three different materials: cobalt-chromium alloy, polyether ether ketone (PEEK), and titanium alloy. In ANSYS Work Beach 2023 R2 software, vertical loads of 70 N, tilted 45° along the long axis of the tooth loads of 70 N, and a 10 N load on the surface of the wire loop were applied to the occlusal surfaces of models 46 and 84, simulating centric and lateral occlusions during chewing with the wire loop space maintainer in place. The stress states of the wire loop space maintainer and supporting teeth were analyzed. RESULTS: Under various loading conditions, the maximum principal stress of the ring wire loop space maintainer was significantly lower than that of the full crown. Stress contour maps indicated that the peak of the maximum principal stress occurred at the junction of the wire loop and crown structure, indicating that this area was more susceptible to fracture. The ring wire loop space maintainer made from PEEK material exhibited the lowest maximum shear stress on the internal organizational surfaces, with equivalent stresses of 23.18 MPa and 36.35 MPa for models 46 and 84, respectively. Stress contour maps demonstrated that the maximum stress on tooth 46 was located at its mesial, while the maximum stress on tooth 84 was situated near the root area on its distal, in contact with the wire loop space maintainer. CONCLUSION In cases of second primary molar loss, wearing the digital ring wire loop space maintainer can effectively distribute stress, and the ring wire loop space maintainer made from PEEK material reduces the stress experienced by supporting teeth to some extent, demonstrating its superiority in clinical application.
Finite Element Analysis ; Humans ; Tooth, Deciduous ; Cone-Beam Computed Tomography ; Space Maintenance, Orthodontic/methods* ; Imaging, Three-Dimensional ; Orthodontic Wires ; Dental Stress Analysis ; Mandible ; Stress, Mechanical

Osteonecrosis of the mandible is also called avascular necrosis of the jaw, and it is a rare complication of bisphosphonates. It is characterized with pain, swelling, exposure of bone, local infection and pathologic fractures of the jaw. With the widespread usage of bisphosphonates in bone metastasis of malignant tumors and osteoporosis, this rare complication has received more attention in recent years. Here, we reported a case of bisphosphonates-related osteonecrosis of the jaw (BRONJ) caused by intravenous zoledronic acid for osteoporosis. A 62-year-old female patient with 7-year history of Sjögren's syndrome and 3-year history of osteoporosis developed BRONJ after 3-year treatment of zoledronic acid. Two months before she went to the Peking University International Hospital, she visited the dentist for periodontal purulent secretion and extracted one tooth from the right mandible. However, the condition was not improved and she felt persistent pain and swelling in the right mandible. Hence, she received repeated root curettage, but there was no improvement. Finally, she was diagnosed with osteonecrosis of the mandible based on the digital volume tomography scan, which showed right mandibular osteonecrosis bone destruction. She underwent surgical debridement of the necrotic bone and administered intravenous antibio-tics at the Peking University International Hospital. Histopathological analysis of the bone biopsy further confirmed the diagnosis of BRONJ. Her condition was improved successfully during a 3-year follow-up. Osteonecrosis of the mandible become more common with the increased use of bisphosphonates. Recent study has reported that osteonecrosis of the mandible is more likely to occur in patients with Sjögren's syndrome. In addition, age, long-term and irregular administration of glucocorticoids, irregular oral examination and treatment also might be the risk factors in the pathogenesis of osteonecrosis of the mandible. For the elder osteoporosis patients who would receive or had received bisphosphonate-related drugs, oral health status and the disease states associated with necrosis of the mandible such as Sjögren's syndrome should be comprehensively measured and fully evaluated during the whole process. Furthermore, to better understand and prevent or reduce the occurrence of this complication, we reviewed the patho-genesis, diagnosis, treatment, and prevention of BRONJ.
Humans ; Female ; Middle Aged ; Bisphosphonate-Associated Osteonecrosis of the Jaw/etiology* ; Diphosphonates/administration & dosage* ; Zoledronic Acid ; Imidazoles/administration & dosage* ; Bone Density Conservation Agents/adverse effects* ; Osteoporosis/drug therapy*

OBJECTIVE: To assess the osteogenesis height in maxillary sinus segment one year after zygomatic implantation by imaging methods, and evaluate the influence of patient factors, maxillary sinus anatomical factors and surgical factors on postoperative osteogenesis height. METHODS: This study is a retrospective study, including patients who underwent zygomatic implantation and whose zygomatic implants passed through the maxillary sinus at the Department of Implantology, Peking University School and Hospital of Stomatology from July 2017 to January 2022. Preoperative and postoperative cone beam CT (CBCT)was taken to measure and calculate the average osteogenesis height (AOH) in maxillary sinus segment of the zygomatic implants, then the residual bone height, the width and morphology of the maxillary sinus floor in the buccal and palatal directions were measured. Besides, the integrity of Schneiderian membrane during implant surgery, and the general information of the patients and zygomatic implants were recorded. By comparing anatomical situations and surgical characteristics, the differences of AOH under different conditions were analyzed. Then AOH was divided into two groups (obvious osteogenesis group and non-obvious osteogenesis group) using the median as the threshold, and the influencing factors of osteogenesis were evaluated using mixed effect generalized linear model univariable and multivariable analysis. RESULTS: A total of 47 zygomatic implants were implanted in 24 patients. During the average follow-up period of 12.1 months, there was no implant failure, and the implant survival rate was 100%. Postoperative CBCT showed that 43 zygomatic implants had osteogenic images in the maxillary sinus segment, most of which originated from the floor of the maxillary sinus, and the median AOH was 3.1 mm [interquartile range (IQR): 4.0 mm]. In terms of maxillary sinus width, there were 31 cases (66.0%) of wide type and 16 cases (34.0%) of narrow type. In the aspect of buccal and palatal morphology, 17 cases were taper (36.2%), 20 cases were round (42.6%), and 10 cases were flat (21.3%). The median of residual bone height was 2.8 mm (IQR: 2.2 mm) before operation. Univa-riate analysis of mixed effect generalized linear model showed that postoperative obvious osteogenic rate was related to the residual bone height (OR=2.09, P=0.006). Multivariate analysis showed that the resi-dual bone height (OR=2.55, P=0.022) and the shape of a taper maxillary sinus (OR=11.44, P=0.040) had a significant impact on the postoperative obvious osteogenic rate. CONCLUSION The maxillary sinus floor showed osteogenic images 1 year after the zygomatic implantation surgery. Larger residual bone height and the shape of a taper maxillary sinus may be favorable factors for osteogenesis.
Humans ; Maxillary Sinus/surgery* ; Cone-Beam Computed Tomography ; Retrospective Studies ; Zygoma/diagnostic imaging* ; Male ; Female ; Osteogenesis/physiology* ; Middle Aged ; Adult ; Dental Implants ; Aged ; Dental Implantation, Endosseous/methods*

BACKGROUND: Periodontitis is characterized by alveolar bone resorption, aggravated by osteoblast dysfunction, and associated with intracellular oxidative stress linked to the nuclear factor erythroid 2-related factor 2 (NRF2) level. We evaluated the molecular mechanism of periodontitis onset and development and the role of NRF2 in osteogenic differentiation. METHODS: Primary murine mandibular osteoblasts were extracted and exposed to Porphyromonas gingivalis lipopolysaccharide (Pg-LPS) or other stimuli. Reactive oxygen species (ROS) and 5,5',6,6'-tetrachloro-1,1',3,3'-tetraethylbenzimidazolylcarbocyanine iodide (JC-1) staining were used to detect intracellular oxidative stress. Alkaline phosphatase staining and alizarin red S staining were used to detect the osteogenic differentiation of osteoblasts. Immunofluorescence and western blotting were used to determine the changes in the mitogen-activated protein kinase (MAPK) pathway and related molecule activities. Immunofluorescence colocalization and co-immunoprecipitation were performed to examine the nuclear translocation of NRF2 and its interaction with dual-specific phosphatase 1 (DUSP1) in cells. RESULTS: Ligated tissue samples showed higher alveolar bone resorption rate and lower NRF2 level than healthy periodontal tissue samples. Pg-LPS increased intracellular oxidative stress levels and inhibited osteogenic differentiation, whereas changes in NRF2 expression were correlated with changes in the oxidative stress and osteogenesis rate. NRF2 promoted the dephosphorylation of the MAPK pathway by nuclear translocation and the upregulation of DUSP1 expression, thus enhancing the osteogenic differentiation capacity of mandibular osteoblasts. The interaction between NRF2 and DUSP1 was observed. CONCLUSIONS: NRF2 and its nuclear translocation can regulate the osteogenic differentiation of mandibular osteoblasts under Pg-LPS conditions by interacting with DUSP1 in a process linked to the MAPK pathway. These findings form the basis of periodontitis treatment.
Animals ; NF-E2-Related Factor 2/physiology* ; Lipopolysaccharides/pharmacology* ; Osteoblasts/drug effects* ; Mice ; Porphyromonas gingivalis/chemistry* ; Cell Differentiation ; Osteogenesis ; Dual Specificity Phosphatase 1/metabolism* ; Mandible/cytology* ; Reactive Oxygen Species/metabolism* ; Oxidative Stress ; Periodontitis/metabolism* ; Cells, Cultured ; Male ; Cell Nucleus/metabolism*

Adenoid cystic carcinoma is a malignant tumor of the head and neck, this article reports a case of a large adenoid cystic carcinoma of the skull base, with the lesion involving the sphenoid sinus, sphenoid bone wings, pterygopalatine fossa, nfratemporal fossa, hard palate, and other structures. The treatment plan consisted of surgical excision, primary reconstrction of the surgical defect,and postoperative radiotherapy, resulting in a favorable prognosis for the patient.
Humans ; Carcinoma, Adenoid Cystic/surgery* ; Maxillary Sinus/surgery* ; Maxillary Sinus Neoplasms/surgery* ; Palate, Hard/surgery* ; Skull Base Neoplasms/surgery* ; Surgical Flaps

This report describes a case of adult temporal bone Langerhans cell histiocytosis（LCH） that presented as posterior canal dehiscence syndrome（PCDS）. The patient initially presented with vertigo, tinnitus, and hearing loss. Computed tomography（CT） revealed erosive changes in the mastoid and posterior semicircular canal. After the operation, the patient's hearing and vestibular symptoms disappeared and postoperative recovery was favorable. Adult LCH is relatively rare, and this case serves as an example to discuss the clinical features and treatment options of this disease, followed by a literature review.
Humans ; Histiocytosis, Langerhans-Cell/complications* ; Semicircular Canal Dehiscence/etiology* ; Temporal Bone/pathology*

Objective:To compare the outcomes of simultaneous versus staged nasal bone reduction and septoplasty in the treatment of traumatic nasal bone fractures with associated septal fractures. Methods:Patients with traumatic nasal bone fractures, with or without septal fractures, were recruited from two hospitals and divided into three groups. Group A underwent simultaneous nasal bone reduction and septoplasty, Group B underwent staged nasal bone reduction and septoplasty, and Group C underwent nasal bone reduction only. Nasal appearance scores and nasal congestion Visual Analogue Scale （VAS） scores were measured preoperatively, at 2 weeks postoperatively, and at 3 months postoperatively. For Group B, scores were also recorded at 2 weeks and 3 months after the second-stage surgery. Differences were analyzed using statistical software. Results:Two weeks post-surgery, the nasal appearance scores significantly decreased in all three groups compared to preoperative scores （P< 0.01）, with no statistically significant differences between the groups （P= 0.43, 0.71, 0.58）. In Group A, the VAS score for nasal congestion decreased significantly following simultaneous surgery （P<0.01）. In Group B, there were no significant differences in nasal congestion VAS scores between pre-surgery and post-first-stage, nor between three months post-first-stage and two weeks post-first-stage （P= 0.61, 0.13）. However, the VAS scores significantly decreased after the second-stage surgery compared to pre-surgery, and three months post-second-stage surgery compared to three months post-first-stage surgery （P<0.01）. The VAS scores for nasal congestion at two weeks post-surgery in Group A were lower than those in Group B after the first-stage surgery （P<0.01）. The incidence rates of nasal adhesions post-surgery in Groups A, B, and C were 0%, 6.9%, and 4.3%, respectively. Conclusion:For traumatic nasal bone fractures with associated septal fractures, performing simultaneous nasal bone reduction and septoplasty under general anesthesia using endoscopy is more time-efficient compared to staged surgery, and it results in a lower occurrence rate of post-surgical nasal adhesions.
Humans ; Nasal Bone/surgery* ; Nasal Septum/injuries* ; Treatment Outcome ; Rhinoplasty/methods* ; Male ; Female ; Adult ; Skull Fractures/surgery* ; Fractures, Bone/surgery* ; Middle Aged ; Adolescent

Objective:To evaluate the feasibility, safety and effects of tumor resection in the anterior space of the styloid process via transoral endoscopic medial parapterygomandibular ligament approach. Methods:This retrospective study included 24 patients who were diagnosed with tumors in the anterior space of the styloid process and treated with the transoral endoscopic medial parapterygomandibular ligament approach. Twenty-four patients who underwent surgery by traditional approach were selected on a 1∶1 ratio as control group. We compared the en bloc resection rate, the operation time, amount of blood loss, the postoperative pain VAS score, recurrence rate, length of hospital stay, complication rate between the two groups. Results:Among the 24 patients, pleomorphic adenoma was confirmed in 18 cases （75.0%）, basal cell adenoma in 2 cases （8.3%）, and neurilemmoma in 4 cases （16.7%）. In the transoral endoscopic group, the en bloc resection rate was 91.7%, the maximum tumor diameter was （42.2±12.2） mm, the operative time was （117.9±29.8）min, the blood loss was （36.7±18.7） mL, the postoperative pain VAS score （1.5±0.7）, no recurrence was observed, length of hospital stay was （10.8±2.9） d. Wound dehiscence occurred in one case in the transoral endoscopic group, and no other postoperative complication was observed. There were significant differences in the operation time, blood loss, the postoperative pain VAS score between the two groups, while no difference was found in gender, age, en bloc resection rate and length of hospital stay. Conclusion:The tumor resection in the anterior space of the styloid process via transoral endoscopic medial parapterygomandibular ligament approach was safe, minimally invasive and feasible.
Humans ; Male ; Female ; Retrospective Studies ; Middle Aged ; Adult ; Endoscopy/methods* ; Temporal Bone/surgery* ; Aged ; Young Adult ; Ligaments/surgery*

Objective:To investigate the clinical diagnosis and treatment of IgG4-related disease（IgG4-RD） primarily involving the nasal cavity and skull base. Methods:A retrospective analysis was conducted on the clinical data of 8 patients with IgG4-RD primarily involving the nasal cavity and skull base who visited the Nasal and Skull Base Surgery Department at Xiangya Hospital from October 2017 to January 2024. The cohort comprised 4 males and 4 females, aged 8 to 69 years. Clinical data, laboratory examination results, imaging findings, histopathological results, and treatment plans were collected. The clinical manifestations, diagnosis, treatment and follow-up results of IgG4-RD primarily involving nasal cavity and skull base were summarized and previous literature were also reviewed. Results:The initial symptoms in the 8 patients included nasal congestion, headache, sensory function decline, and facial deformities. Three patients also had parotid and pulmonary involvement. Among the 8 patients, 4 underwent partial surgical resection combined with glucocorticoid therapy; 1 underwent partial surgical resection combined with glucocorticoid and immunosuppressant therapy; 1 received glucocorticoid therapy alone; and 2 received glucocorticoid combined with immunosuppressant therapy. Follow-up was conducted one month after treatment, lasting from 5 to 79 months. During the follow-up period, recurrence was observed in 1 patient treated with glucocorticoid combined with immunosuppressants and in 1 patient treated with glucocorticoid alone, while the other 6 patients achieved significant remission. Conclusion:The diagnosis of nasal cavity and skull base IgG4-RD requires the combination of histopathology, laboratory tests, and imaging results. Treatment primarily includes glucocorticoids or combined immunosuppressants. For patients with significant compression symptoms, sensory function impairment, or facial deformities, surgical resection is an important treatment option. Given the high risk of recurrence, early intervention, active treatment, and long-term follow-up are crucial.
Humans ; Male ; Skull Base/pathology* ; Female ; Middle Aged ; Retrospective Studies ; Aged ; Nasal Cavity/pathology* ; Adult ; Immunoglobulin G4-Related Disease/therapy* ; Immunoglobulin G ; Child ; Young Adult ; Adolescent