Surgical operation is the main treatment of oral and maxillofacial tumors.Dysphagia is a common postoperative complication.Swal-lowing disorder can not only lead to mis-aspiration,malnutrition,aspiration pneumonia and other serious consequences,but also may cause psychological problems and social communication barriers,affecting the quality of life of the patients.At present,there is no systematic evalua-tion and rehabilitation management plan for the problem of swallowing disorder after oral and maxillofacial tumor surgery in China.Combining the characteristics of postoperative swallowing disorder in patients with oral and maxillofacial tumors,summarizing the clinical experience of ex-perts in the field of tumor and rehabilitation,reviewing and summarizing relevant literature at home and abroad,and through joint discussion and modification,a group of national experts reached this consensus including the core contents of the screening of swallowing disorders,the phased assessment of prognosis and complications,and the implementation plan of comprehensive management such as nutrition management,respiratory management,swallowing function recovery,psychology and nursing during rehabilitation treatment,in order to improve the evalua-tion and rehabilitation of swallowing disorder after oral and maxillofacial tumor surgery in clinic.

Neck dissection and reconstruction are two important aspects of oral cancer treatment.There are various surgical methods for neck dissection and reconstruction,but all of them are performed by open surgery.This article reports a full endoscopic neck dis-section through the retroauricular hairline approach,the radical resection of the intraoral tumor and the repair of the defect by superfi-cial circumflex iliac artery perforator flap with in situ vascular anastomosis intraorally.The incision is located in the hairline,hidden and invisible,and there is no exposed surgical scar on the neck after surgery.This paper introduces the technique of scarless neck dissection combined with free skin flap repair for the treatment of oral cancer and discusses its advantages and disadvantages.

Objective:To explore a set of procedures for the effictive granulation of cartilage,and to construct injectable cartilage graft with platelet-rich gel(PRG),and to evaluate its effects in nude mice models.Methods:The costal cartilage of adult male rab-bits was cut into pieces and placed in a mortar for 30-60 s freezing in liquid nitrogen and grinding for a short time to obtain granular cartilage.Blood was collected from the middle ear artery and PRG was prepared by double centrifugation.Granular cartilage and the mixture of granular cartilage and PRG were injected subcutaneously in nude mice of control group(n=5)and experimental group(n=5)respectively.8 weeks after injection,the gross morphology observation and histological examination were pertormed.The nasal dor-sum augmentation model of nude mice was established in the experimental group.Results:The cartilage particles were in the size of 10-500 pm in diameter after frozen grinding,and injection could be realized.In vitro culture showed that the cell survival rate of granular cartilage reached to 80％.In vivo test showed that the sample morphology of the control group was insignificant,and the sur-face was grainy.That of the experimental group was well maintained,and the surface was smooth with obvious capillaries.The sam-ples of experimental group achieved significant augmentation in the nude mouse model of nasal dorsum augmentation.Conclusion:Freeze-milling technology can achieve efficient granulation of cartilage,and the graft constructed with PRG gel is suitable for maxillo-facial cartilage transplantation repair.

Objective:To explore the correlation between c-myc and glutaminase(GLS)and glutamine synthase(GS)in oral epider-moid carcinoma cells in animal models.Methods:Immunohistochemistry was used to detect the expression of c-myc,GLS and GS in clinical samples of oral cancer.KB cell model with stable and high expression of c-myc was established and verified,then the KB cells were transplanted into nude mice to establish mouse tumorigenic models.The cells and nude mouse models were respectively diveded into 3 groups(n=6):normal cotnrol,empty vector and c-myc overexpression groups.The tumor growth was observed.The expression of c-myc,GLS and GS in the cells and the tumor samples was detected by immunohistochemistry.Results:c-myc,GLS and GS were highly expressed in clinical samples of oral cancer.In the cells of c-myc overexpression group c-myc mRNA expression level was sig-nificantly higher than that of empty vector control group.The tumorigenic models were formed in all nude mice of the groups,and the volume and weight of the c-myc overexpression group increased more significantly(P＜0.01),in the c-myc overexpression group c-myc was overexpressed,the expression of GLS and GS was significantly higher than that in the other 2 groups.Conclusion:c-myc is highly expressed in oral cancer,and may up-regulate GLS and GS expression.

Objective:To assess the impact of reducing the mesh density on the overall volume and trueness of single-crown restora-tions.Methods:15 single-crown restorations were included,and their mesh density in 3D software was simplified by 75％,50％,25％,10％and 5％respectively.The overal volume,file size and mesh edge length of the restorations with different reduction levels were compared.Deviation analysis was conducted by curving clipping the area of the shoulder,tissue surface(except for the shoulder)and occlusal surface of the restorations and compared with those of the corresponding regions in the non-simplified restorations.Trueness was assessed using the root mean square(RMS)values for the volume and trueness of different areas.Results:Reducing the mesh den-sity did not significantly affect the overal volume of the single-crown restorations(P＞0.05),but it had a significant impact on the file size(P＜0.001),mesh edge length(P＜0.001)and the trueness of the shoulder(P＜0.001),tissue surface(except for the shoulder)(P＜0.001)and occlusal surface(P＜0.001)areas.Conclusion:Reducing the mesh density had little impact on the overall volume of the restorations but significantly affected their trueness.

Objective:To investigate the response of mandibular condylar chondroprogenitors to flow fluid shear stress(FFSS).Methods:Chondroprogenitors were in vitro cultured and stimulated with FFSS that can cause cell degeneration,and treated with sec-ond-generation high-throughput RNA sequencing.Differential gene expression was screened using DESeq2 software for gene ontology(GO)functional enrichment analysis,kyoto encyclopedia of genes and genomes(KEGG)pathway enrichment analysis and protein-protein interaction(PPI)network analysis.qRT-PCR was performed to validate the core genes screened by PPI.Results:A total of 1996 differentially expressed genes were obtained,mainly including inflammatory response and cell cycle related molecules.Among them,Actal,Atf3,Ccl2,116,Nfkbia,Ret and Vcaml were identified as the core genes.Conclusion:FFSS stimulation affects chondroprogenitor function by acting on inflammatory responses and cell cycle-related signaling pathways in chondroprogenitors.

Objective:To establish the animal model of cervicofacial venous malformations(VMs)by surgical reconstruction of exter-nal jugular vein in sheep.Methods:The external jugular veins of 5 sheep were dissected,and the position,course,branch and exter-nal diameter were observed and measured.The models of VMs with draining and returning veins were constructed by suturing or constric-ting the proximal part of main trunk and ligating or constricting the distal part of the jugular or branch veins.The animal model was eval-uated by Doppler ultrasound,gross observation and histological observation at the 4th week after surgery.Results:The external jugular veins of sheep is in the lateral side of bilateral neck,and the main trunk is formed by the maxillary vein and lingual facial vein.The ex-ternal diameter ranges from 6 to 12 mm,with an average external diameter of 9.3 mm.Immediately after the external jugular vein was sutured and narrowed at the proximal part of the main vein,the distal part of the vein branch was ligated or narrowed,the blood flow speed slowed down and the veins in the model area bulged.4 weeks after surgery,gross observation showed that most veins narrowed and thrombosis was formed in part of the venous lumen.The central region of some specimens was dilated,and the peripheral collateral veins were dilated in some models.Doppler ultrasonography showed that the lumens of most veins were dilated and the returning veins and the inflow veins were narrowed.Colored blood flow was seen in the lumen.Histological observation showed that the structure of vein endothelium and wall was close to the normal vein,and the vein vessel wall of some specimens was thickened.Conclusion:The VMs model estab-lished by external jugular vein of sheep basically meets the re-quirements and is expected to be used in the therapeutic meth-odology research of cervicofacial VMs.

Objective:To explore the role of long non-coding RNA rhabdomyosarcoma 2 associated transcript(lncRNA RMST)and microRNA-24-3p(miR-24-3p)in proliferation,migration and invasion of oral squamous cell carcinoma cells(OSCCs).Methods:The RMST expression in head and neck squamous cell carcinoma(HNSC)was analyzed by UALCAN data base.qRT-PCR was used to detect the expression of RMST and miR-24-3p in 5 human OSCC cell lines.CAL27 cells were in vitro cultured and allocated into con-trol group,pcDNA3.1 group(vector),pcDNA3.1-RMST+mimics-NC group(overexpression of RMST+negative control of miR-24-3p)and pcDNA3.1-RMST+miR-24-3p mimics group(overexpression of RMST+miR-24-3p).Dual luciferase reporter assay was per-formed to analyze the interaction between RMST and miR-24-3p.MTT assay,wound-healing and transwell assay were applied to de-tect the proliferation,migration and invasion of the cells.Western blot and qRT-PCR were conducted to measure the expression of E-cadherin,N-cadherin and c-myc in the cells.Results:RMST level were down-regulated in HNSC tissues and OSCC cell lines(P＜0.01).While miR-24-3p level was elevated in OSCC cell lines(P＜0.01).miR-24-3p was identified and confirmed as a potential binding partner to RMST.miR-24-3p level was lower in pcDNA3.1-RMST group than in pcDNA3.1 group(P＜0.01).The prolifera-tion,migration and invasion abilities of CAL27 cell in pcDNA3.1-RMST+mimics-NC group were lower than in pcDNA3.1 group(P＜0.01).While those of CAL27 cells in pcDNA3.1-RMST+miR-24-3p mimics group were higher than in pcDNA3.1-RMST+mimics-NC group(P＜0.01).Compared with pcDNA3.1 group,pcDNA3.1-RMST+miR-24-3p mimics showed higher expression of E-cad-herin,lower expression of N-cadherin and c-myc(P＜0.01).Compared with pcDNA3.1-RMST+miR-24-3p mimics group,pcD-NA3.1-RMST+miR-24-3p mimics group showed lower expression of E-cadherin,higher expression of N-cadherin and c-myc(P＜0.01).Conclusion:Down-expressed RMST may suppress the proliferation,migration and invasion progression of OSCC cells through targeting miR-24-3p.

Objective:To investigate the effects of 3 adhesives on the bond force and durability of polished and glazed zirconia ceram-ics to orthodontic metal brackets respectively.Methods:Universal adhesives,Single Bond Universal(SBU)and Prime&Bond Universal(PBU)were respectively used to bond polished and glazed zirconia to metal braces of maxillary central incisors using TransbondTM MIP(TM)as the control.The shear bond strength(SBS),the fracture morphology and adhesive residual index(ARI)were examed after wa-ter bath or water bath-thermal cycling storage.Results:The adhesive(P＜0.001)and storage conditions(P＜0.001)significantly af-fected the shear bond strength of zirconia to brackets.There was no significant difference between the polished or glazed groups(P=0.09).SBU showed the stronger SBS and lower ABI,there were significant differences in ARI scores among the 3 cements(P＜0.001).Conclusion:SBU may have better bonding performance than PBU and TM in the orthodontic bonding of polished or glazed zir-conia surfaces to the zirconia ceramics.

Objective:To retrospectively evaluate the clinical outcomes of autonomous dental implant robot(ADIR)assisted implant surgery in 1-year follow-up.Methods:20 patients with tooth missing underwent implantation surgery by ADIR were incuded.The plat-form deviation,apex deviation and angular deviation of the implants were analyzed.The marginal bone height and peri-implant soft tis-sue health were measured and observed immediately,6 months and 12 months after the restoration.Results:The platform deviation,apex deviation and angular deviation of 20 implants at the 3 follow-up examinations were(0.34±0.11)mm,(0.34±0.15)mm and(0.82°±0.38°),respectively.There was no significant difference in the accuracy of different implant diameter and length(P＞0.05).During the follow-up period,all implants had successful osseointegration,stable marginal bone height,and acceptable peri-implant soft tissue condition.Conclusion:The 1-year follow-up indicates that ADIR can achieve promising clinical performance.Long-term follow-up studies are still necessary for verification.