The 5th edition of the Classification of Head and Neck Tumours by the World Health Organization (WHO) was published in March 2022. In the section on oral cavity and mobile tongue tumours, the classification of epithelial tumours in the 5th edition has undergone several modifications compared to the 4th edition published in 2017. Notably, oral potentially malignant disorders (OPMD) and oral epithelial dysplasia (OED) have been addressed separately, and in-depth discussions have been included regarding submucosal fibrosis (SF) and human papillomavirus (HPV)-associated oral epithelial dysplasia (HPVOED). Additionally, the section on squamous cell carcinoma (SCC) now includes carcinoma cuniculatum (CC) and verrucous carcinoma (VC), emphasizing their distinctive clinical and histological characteristics. This review provides a comprehensive overview of the most recent advancements in clinical, histological, and molecular research on epithelial tumours of oral cavity and mobile tongue since 2017.

Objective: To investigate the effect of local injection of desferrioxamine (DFO) on the bone remodeling of alveolar bone through the regulation of osteoclasts by hypoxia inducible factor-1α (HIF-1α). Methods: DFO was injected locally into the alveolar bone of C57 mice; changes in alveolar bone volume were observed by micro-CT and histological staining; osteoclastogenesis was observed by immunofluorescence and tartrate-resistant acid phosphase (TRAP) staining; the effects of DFO on the differentiation of Raw264.7 to osteoclasts via HIF-1α were observed in vitro by TRAP staining and immunofluorescence. Results: Micro-CT and histological staining showed that local bone density decreased and bone volume decreased after local injection of DFO; histological staining revealed that the number of local osteoclasts increased and HIF-1α expression increased in the DFO injection group compared with the control group; in vitro cell culture revealed that DFO promoted the expression of HIF-1α in Raw264.7 cells and its differentiation to osteoclasts. Conclusion: Local injection of DFO can promote bone remodeling of alveolar bone and differentiation of Raw264.7 into osteoclasts.

Objective: To observe the effect of resveratrol on the chemoresistance of oral squamous cell carcinoma (OSCC) cells induced by cisplatin (DDP), and to explore the related mechanism. Methods: CAL-27/DDP cells in logarithmic phase were taken and randomly divided into control group (conventionally cultured), resveratrol group (added resveratrol 200 μmol/L), agonist group [added tumor necrosis factor-α (TNF-α) 10 ng/mL], resveratrol combined with agonist group (added resveratrol 200 μmol/L, TNF-α 10 ng/mL). All groups were cultured for 48 h for subsequent experiments. The inhibition rate of cell proliferation was detected by MTT method. Double staining was used to detect the apoptosis rate. Intracellular DDP accumulation and retention were examined. Western blotting was used to detect the protein expressions of P-glycoprotein (P-gp), topoisomorases Ⅱ (Topo Ⅱ), nuclear factor-κB (NF-κB) p65, phosphorylated NF-κB (p-NF-κB) p65, inhibition of NF-κBα (IκBα) and phosphorylated IκBα(p-IκBα). Results: Compared with the control group, the proliferation inhibition rate, apoptosis rate, drug accumulation, drug retention, and TopoⅡprotein expression were increased, and the expression of P-gp protein, as well as the ratios of p-NF-κB p65/NF-κB p65, p-IκBα/IκBα protein expression were decreased in the resveratrol group (P<0.05). Also compared with the control group, the proliferation inhibition rate, apoptosis rate, drug accumulation, drug retention, and Topo Ⅱ protein expression were decreased, P-gp protein expression, p-NF-κB p65/NF-κB p65, p-IκBα/IκBα protein expression ratios were increased in the agonist group (P<0.05). Compared with the resveratrol group, the proliferation inhibition rate, apoptosis rate, drug accumulation, drug retention, and TopoⅡprotein expression were decreased, while the expression of P-gp protein, and the ratios of p-NF-κB p65/NF-κB p65, p-IκBα/IκBα protein expression were increased in the resveratrol combined agonist group (P<0.05). Compared with the agonist group, the proliferation inhibition rate, apoptosis rate, drug accumulation, drug retention and TopoⅡprotein expression were increased, while the expression of P-gp protein and the ratios of p-NF-κB p65/NF-κB p65, p-IκBα/IκBα protein expression were decreased in the resveratrol combined with agonist group. Conclusion: Resveratrol can reduce the chemotherapy of cisplatin-induced OSCC cells, and its mechanism may be related to the inhibition of NF-κB pathway.

Objective: To investigate the expression and clinical significance of E2F transcription factor 1 (E2F1) in oral squamous cell carcinoma (OSCC), and to analyze its function in apoptosis and cell cycle. Methods: The correlation between E2F1 expression and clinicopathology in OSCC was analyzed based on R language and The Cancer Genome Atlas (TCGA) database. The main biological processes involved in E2F1 were identified by gene set enrichment analysis (GSEA). Western blotting and real-time quantitative polymerase chain reaction (RT-qPCR) were used to detect E2F1 expression in OSCC patients' tissue. After increasing and knocking down the expression of E2F1 in SCC15 cell lines by cell transfection, the effect of changes in E2F1 expression on apoptosis and cycle of SCC15 cells was analyzed by flow cytometry. Results: E2F1 was highly expressed in the OSCC-related TCGA dataset and correlated with T-stage (T2 or T4 vs T1), histological grade (G2 or G3 vs G1), clinical stage (Ⅲ vs I), age (middle vs young), and gender (male vs female) (P<0.05), which were mainly enriched in the genome of cell cycle or nucleotide excision repair [P<0.05 and false discovery rate (FDR) <0.25]. Both mRNA and protein expression of E2F1 were upregulated in the tissues of 37 OSCC patients (P<0.001). The expression of upregulated E2F1 decreased the rate of apoptosis in SCC15 cells (P<0.05), and also decreased the rate of G1 phase (P<0.01) and increased the rate of S phase (P<0.001) in the cell cycle. Conclusion: E2F1 is highly expressed in OSCC and can inhibit apoptosis and promote G1/S phase transition in the cell cycle.

Objective: To explore the clinical effect of Piezocision guided by three dimensions (3D) printing guide plate to assist skeletal Class Ⅱ malocclusion correction. Methods: Twenty-four patients with skeletal Class Ⅱ malocclusion were selected from our hospital. The treatment plan involved the extraction of the bilateral maxillary first premolars and anterior retraction by mini-implant anchorage in upper arch. The patients were randomly divided into two groups: The control group underwent conventional orthodontic treatment, while the research group underwent Piezocision guided by 3D printing guides at the beginning of the space-closing phase of the orthodontic treatment. The loading method was the same as that of the control group after the operation. The indexes related to the changes of hard and soft tissues and the treatment effects of the two groups were recorded for analysis and comparison. Results: In the research group, the change value of U1-SN was (-1.49±2.18)°，U1-NA was (-5.63±3.39)°，NA-Apo was -4.10 (-4.60, -2.00)°，U1-Apo was (-3.10±0.95) mm. There was significant difference comparing with the control group. The average speed of movement of the teeth in the research group during the process of space closure was (0.90±0.21) mm per month, which was significantly faster than that of the control group [(0.54±0.15) mm per month]. None of the roots were damaged after operation, and there was no significant difference in the degree of root resorption and the depth of periodontal probing between the research group and the control group after the treatment. Conclusion: In skeletal ClassⅡmalocclusion correction, 3D printing-guided Piezocision can effectively realize the overall movement of the maxillary anterior teeth, shorten the treatment time, and have fewer surgical complications, which can be viewed as an effective adjuvant treatment of patients with skeletal ClassⅡmalocclusion undergoing orthodontic treatment.

Objective: To establish a design program for orthognathic surgical splints based on artificial intelligence (AI), and to compare the precision between the AI splints and manual digital splints. Methods: This research established an AI algorithm for orthognathic surgical splints and obtained the available automatic design program. The time required for designing surgical splints in the same case was compared. Besides, 40 dentition models of patients with skeletal Class Ⅱ malocclusion (20 for mandibular surgery, and 20 for bimaxillary surgery) were included for comparison. The splints were designed by AI program and manual digital software respectively and scanned for the digital data to compare the difference. Results: The overall deviation between the AI and manual digital splints in guiding the positioning of the models was less than 0.1 mm, indicating that there was no significant difference between them. Comparison of cusp position showed that the mean deviation distance between the AI and manual digital splints was about 0.10-0.14 mm. The application of the AI program can greatly reduce the design time in both the mandibular surgery [(10.7±2.4) s] and the bimaxillary surgery [(21.5±3.9) s]. Conclusion: There is no significant difference in accuracy between AI and manual digital splints, and AI program can improve the design efficiency of orthognathic surgical splints.

Objective: To compare the influence between retromandibular transmasseteric anterior parotid approach (RMTMAP) and retromandibular transparotid approach (RMTP) on the facial nerve damage and salivary fistula in the treatment of condylar fractures. Methods: A comprehensive literature search of randomized controlled trials on surgical approaches for condylar fractures was undertaken in various Chinese and English databases (the Cochrane Library, PubMed, Embase, CNKI, CBM, VIP, Wanfang and Chinese Clinical Trial Registry). The search period is from the establishment of the database until now (November 2021), and manual search is carried out to avoid omissions. A total of 7 studies restricted in randomized controlled trials were included, and the quality of these studies was moderate to high. RevMan 5.3 software was used to perform meta analysis. Results: A total of 7 studies were included in this study, and the results showed that patients in both groups could achieve satisfactory results after surgery. The incidence of postoperative facial nerve injury in RMTMAP group was lower than that in RMTP group [relative risk (RR)=0.49, 95%CI=0.25-0.97]. P=0.04], and the incidence of postoperative salivary fistula was lower in the RMTMAP group (RR=0.35, 95%CI=0.15-0.85, P=0.02). The difference between the two groups was statistically significant. Conclusion: A lower incidence of postoperative facial nerve injury and salivary fistula was observed in RMTMAP group than that in RMTP group. Therefore, RMTMAP deserves clinical application.

Objective: To investigate the effect of fibular free flap on reconstruction of postoperative defects after radiation-induced bilateral osteoradionecrosis of the jaw (ORNJ). Methods: Seven patients with radiation ORNJ who were referrd to Department of Oral and Maxillofacial Surgery in our hospital from January 2010 to November 2020 were retrospected. Among the cases, 6 males and 1 female, aged 42 to 56 years old, were included. All patients had primary nasopharyngeal carcinoma, and recurrent nasopharyngeal carcinoma was excluded. Fibular free flap was used to reconstruct bilateral osteoradionecrosis of the mandible. The fibular osteotomy and tissue flap survival, complications in donor and recipient areas, and postoperative mouth opening were evaluated for reconstruction outcomes. Results: After 10 to 30 months of follow-up, free fibular composite flap was successfully used to reconstruct mandibular defects. Facial artery was selected in 5 cases, superior thyroid artery in 2 cases, and end-to-side anastomosis of internal jugular vein was performed in all recipient veins. One patient developed venous crisis 6 hours after surgery. Emergency surgical exploration revealed that the vein was twisted during end-to-side anastomosis and recovered well after re-anastomosis. The harvested fibula was 17.5-21.0 cm in length. No patient had serious donor or recipient site complications. All patients had satisfactory facial shape, remaining normal occlusion, and mouth opening was 2.5-3.3 cm. Conclusion: Fibular myocutaneous flap can reconstruct the bilateral mandibular soft and hard tissue defects after radiation in patients with ORNJ, which is worthy of clinical application.

Objective: To explore the application effect of light sedation technique in impacted tooth extraction in patients with anxiety. Methods: Intravenous infusion of propofol was administered to 20 patients with mandibular impacted teeth anxiety, and the impacted teeth were removed when the bispectral index (BIS) reached 80-85. The patients' heart rate (HR), mean arterial pressure (MAP), respiratory rate and blood oxygen saturation were monitored during operation, and the patients were instructed to record the visual analogue scale (VAS) after operation, and were asked about anterograde amnesia. SPSS 20.0 software package was used for data statistics, paired t test was used to compare the differences between intraoperative physiological indexes and the time of admission, and descriptive analysis was used to analyze the intraoperative pain of the patients. Results: All patients successfully completed the operation, and there were no obvious adverse reactions during the operation.There were no abnormalities in HR, MAP, respiratory rate and blood oxygen saturation. The postoperative VAS scores of the patients were 1-3, and the patients' anterograde amnesia of the start of surgery, mucosal incision and dental drill sound were recorded, which means that the anxiety was relieved. Conclusion: For the removal of mandibular impacted teeth in patients with dental anxiety, propofol intravenous light sedation technology (BIS=80-85) can achieve satisfactory results, reduce patients' anxiety and improve comfort.

Objective: To investigate the clinicopathological features and prognosis of recurrent pleomorphic adenoma (RPA) of minor salivary glands. Methods: The clinical data of patients with RPA of minor salivary glands in our hospital from January 2011 to December 2020 were retrospectively collected. In combination with literature review, the clinicopathological characteristics and prognosis were analyzed. Results: A total of 17 cases of RPA of minor salivary glands were collected, including 5 males and 12 females. The age ranged from 14 to 80 years, with a median age of 52 years. The average recurrence frequency was 2.8 times, and the average recurrence interval was 7.9 years. It was most common in the palate (52.9%), followed by the buccal (29.4%). Large recurrent tumors may cause certain symptoms, such as bone absorption, pharyngeal cavity obstruction and facial swelling. A total of 7 (41.2%) of 17 patients underwent malignant transformation, and 5 (55.6%) of 9 cases in the palate underwent malignant transformation. The prognosis of surgical treatment was good, with an average follow-up of 5.7 years, and 15 patients (88.2%) were tumor-free status. Conclusion: RPA of minor salivary glands is a rare critical tumor, which often occurs in the palate and has a long recurrence interval. RPA of small salivary gland is prone to undergo malignant transformation, and the prognosis of surgical treatment is good.

The structural and functional heterogeneity of cells in bone tissue is closely related to their spatial location. Spatial transcriptomics can simultaneously obtain location information and transcriptome changes of spatial units within tissues. In recent years, the rapid development of spatial transcriptomics has enabled high-resolution and high-throughput transcriptome analysis of tissues and organs, and has been continuously applied in the study of the skeletal system. This article reviews the progress of spatial transcriptomics and its applications in bone research.

Temporomandibular joint osteoarthritis (TMJOA) is a common clinical disease. However, the pathogenesis of TMJOA is still unclear, and there is a lack of effective treatment, bringing great distress to patients. Therefore, it is of great significance to explore the pathogenesis of temporomandibular arthritis and to find effective therapy. Recent studies have shown that noncoding RNA (ncRNA) is involved in regulating the development of TMJOA and has great potential in the diagnosis and treatment of TMJOA. Thus, ncRNA is expected to become new diagnostic marker and therapeutic target. We will review the research progress of noncoding RNA in temporomandibular arthritis.

The role of bone marrow mesenchymal stem cells (BMSCs) in bone defect repair and bone regeneration has been extensively studied. Much evidence suggests that effective endogenous bone regeneration requires coordination of the immune system. The interaction between immune cells and BMSCs is crucial to promoting bone formation in the healing of bone defects. In recent years, it has been found that a variety of immune cells promote osteogenic differentiation of BMSCs through the release of cytokines and signals. It is beneficial to bone defect repair and bone regeneration, and becomes a new therapeutic target for bone defect repair. Therefore, this article reviews the research status of the osteogenic effect of immune cells on BMSCs and related mechanisms.

Carcinosarcoma (CS) is a highly malignant tumor composed of malignant epithelial elements and malignant mesenchymal elements, with a very low incidence rate. This paper reports a case of parotid carcinosarcoma composed of salivary duct carcinoma and angiosarcoma, and discusses the incidence, immunohistochemical analysis, diagnosis and differential diagnosis, pathogenesis, tissue source, treatment and prognosis of parotid carcinosarcoma in combination with relevant literature in order to improve clinicians' further understanding of the disease and improve the further classification of parotid carcinosarcoma pathology.

Objective: To discuss the clinical and pathological features, differential diagnosis, treatment and prognosis of low-grade myofibroblastic sarcoma (LGMS), and report a case of LGMS that occurs in children's mandibular gingiva to raise awareness of this disease among clinicians. Methods: Analyze the clinical data, treatment, and pathological result of a child with LGMS in the right mandibular gingiva with jaw destruction, and the relevant LGMS at home and abroad were analyzed and summarized. Results: Due to a painless mass in the right mandibular gingiva, the patient came to hospital for surgical treatment, and the pathological result was gingival tumor. Recurrence occurred two weeks after surgery, so we did the second enlargement surgery, and the pathological result was LGMS. Conclusion: LGMS is a rare tumor derived from mesenchymal tissue, which tends to occur in the oral cavity and has no obvious clinically specific symptoms. It requires histopathological examination to confirm the diagnosis, and it should be distinguished from diseases such as inflammatory myofibroblastic tumor and leiomyosarcoma. Surgical enlargement is usually used clinically and the patient should be followed up for a long time.