The establishment of a standardizing document for the clinical practice of oro-maxillofacial cone-beam CT(CBCT)is a prerequisite for ensuring the rational use of CBCT, obtaining accurate diagnostic and therapy information, as well as safeguarding the reasonable rights and interests of patients. During the past 20 years of CBCT development, nearly 30 standardizing documents including statements, consensus and guidelines related to CBCT clinical practice have been published internationally, providing guidance for local practitioners in all aspects of CBCT use. These standardizing documents differ in terms of content and methodology. With the recent refinement of the methodology related to clinical practice guidelines, as well as the demand for high-quality standardizing documents from academic associations and institutions at all levels, the future development and updating of standardizing documents related to CBCT will need to be at a higher level in terms of both completeness and scientific validity. In view of this, the current article reviewed and summarized the contents and methods of published standardizing documents, with a view to providing references for the development of high-quality CBCT clinical practice guidelines in China.

Objective To explore the expression and role of LncRNA LINC00958 in head and neck squamous cell carcinoma(HNSCC). Methods The expression of LINC00958 in HNSCC and its effect on survival and prognosis were analyzed using TCGA database. HNSCC cell lines CAL27 and HN6 were cultured in vitro, and the transfected control group and knockdown group(si-LINC00958)plasmid were detected by real-time quantitative PCR and western blotting(WB)assay. The cell proliferation ability was detected by CCK-8 assay. The changes of cell migration and invasion ability were detected by transwell assay. The expressions of transfer-related proteins E-cadherin, N-cadherin and vimentin were detected by WB assay. The binding sites of LINC00958 and miR-877-3p were predicted by TargetScan database, and verified by double luciferase reporter gene assay. The effects of miR-877-3p on proliferation, migration and invasion of HNSCC cells were analyzed. Results LINC00958 was highly expressed in HNSCC and affected the overall survival rate(P<0.05). Compared with the control group(si-NC), the proliferation, migration and invasion of cells in si-LINC00958 group were decreased; the expression of E-cadherin was decreased, and the expression of N-cadherin and Vimentin was increased(P<0.05). The TargetScan database showed that miR-877-3p was the target gene of LINC00958, and the targeting relationship between miR-877-3p and LINC00958 was verified by double luciferase reporter gene assay. Compared with the control group(NC), cell proliferation, migration and invasion in miR-877-3p mimics group were significantly decreased(P<0.05). Conclusion LINC00958 promotes the proliferation, migration and invasion of HNSCC by targeting miR-877-3p.

Objective To investigate the effect of CGF on promoting the osteogenesis of the mandible symphysis in rats, and to preliminarily explore the possible mechanism. Methods A total of 24 rats were randomly divided into three groups: Collagen group, Collagen + CGF group, CGF group. Three and six months after operation, the rats were killed in two batches. The in vitro specimens were photographed by micro-CT, and the radiological manifestations of each group were compared by three-dimensional reconstruction and cross-section. Statistical analysis was conducted according to standard scores. The specimens were decalcified after micro-CT, and histological sections were made to compare differences among the groups. Results Statistical analysis showed that at the 3rd month, the score of CGF+Collagen group was significantly higher than that of CGF group and Collagen group(P=0.026 6,P=0.026 6), but there was no significant difference between CGF group and Collagen group. At the 6th month, CGF+Collagen group had a significant advantage compared with CGF group and Collagen group(P=0.002 1,P=0.010 1). Collagen group seemed to be better than CGF group, but there was no statistical difference. Through HE staining, it was found that the score of CGF+Collagen group was significantly better than that of CGF group and Collagen group at the 3rd month(P=0.003 8,P=0.003 8), but there was no significant difference between CGF group and Collagen group. At the 6th month, compared with CGF group and Collagen group, the score of CGF+Collagen group was still significantly higher than that of Collagen group (P=0.008 2,P=0.019 4). The score of Collagen group was slightly higher than that of CGF group, but there was no significant difference. Conclusion The combination of CGF and Collagen can significantly promote the healing of bone defects, but the effect of CGF alone on bone defects is not ideal.

Objective To investigate the biological function and mechanism of miR-191-5p regulating OSCC cells. Methods The expression of miR-191-5p in oral squamous cell carcinoma patients was analyzed by bioinformatics method, and the possible target gene TJP1 was screened out through the relevant database. The targeting relationship between the two was verified by dual-luciferase experiment. In vitro transfection was divided into blank, inhibitor NC (negative control group) and miR-191-5p inhibitor (knockdown miR-191-5p group). After knocking down miR-191-5p, the transfection efficiency was verified by qRT-PCR, and the effects of miR-191-5p on the proliferation, invasion and migration ability of Cal-27 cells were detected by CCK-8 proliferation experiment, cell cloning experiment, Transwell and scratch experiment. Western blotting detected the expression of TJP1 protein and EMT-associated proteins. siRNA-TJP1 was transfected into miR-191-5p low-expressing cells and the effect of simultaneous down-regulation of TJP1 on the proliferation and migration capacity of Cal-27 cells was observed. Results miR-191-5p expression was up-regulated in OSCC tissues and cells, while down-regulation of miR-191-5p inhibited the proliferation, invasion and migration capacity of Cal-27 cells and EMT tendency. miR-191-5p targeted and inhibited the expression of TJP1, while down-regulation of TJP1 reversed the inhibition of Cal-27 cell proliferation and migration by knocking down miR-191-5p. Conclusion The proliferation, invasion and migration of OSCC cells is inhibited by targeting TJP1 under miR-191-5p, and miR-191-5p may increase tumor metastasis by regulating the EMT pathway.

Objective To prepare polyethylene glycol (PEG)-polylysine (PLL) injectable hydrogel with inherent antibacterial adhesion, and explore its various functions and effects in the treatment of periodontitis. Methods ε-polylysine was crosslinked with 4-arm-PEG-SG to obtain hydrogel through amidation reaction. The materials were characterized by Fourier transform infrared spectroscopy and scanning electron microscopy. The antibacterial properties, biocompatibility, gel time, swelling and mechanical properties of the materials with different ratios were investigated to determine the best ratio. The study also evaluated the hydrogel’s adhesion strength. A rat model of periodontitis was constructed to observe the therapeutic effects of PEG-PLL hydrogel. Results PEG-PLL hydrogel was successfully constructed. When the concentration of PLL was 20 mg/mL, the hydrogel had good antibacterial properties, mechanical property, gel time, low swelling rate, and no obvious cytotoxicity. It can produce adhesion strength of about 15 kPa. In vivo experiments proved that the hydrogel can effectively prevent the further development of periodontal bone defects and promote the repair. Conclusion PEG-PLL hydrogel has good inherent antibacterial activity, biocompatibility and tissue adhesion, which can promote the repair of periodontal bone defects.

Objective To verify the effect of triamcinolone acetonide(TA) and normal saline(NS) irrigating salivary glands on long-term relief of xerostomia in patients with Sjögren’s syndrome(SS). Methods A total of 49 SS patients were randomly divided into control group (no irrigation, n=16), NS group(NS irrigation, n=17) and TA group(TA irrigation, n=16). The examinations of the unstimulated whole salivary flow(UWS), chewing-stimulated total salivary flow(SWS), citric acid-stimulated parotid flow(SPF), clinical xerostomia score(CODS), xerostomia scale(XI) and EULAR SS patient-reported index(ESSPRI) were conductedat 1 week before irrigation(0W) and 8 weeks(8W), 16 weeks(16W), 32 weeks(32W) and 40 weeks(40W) after irrigation. Results The follow-up of 14 cases in each group was completed. Compared with 0W, the SWS and SPF of 8W, 16W, 24W and 32W were increased after TA and NS irrigation(P<0.05), but there was no significant difference at 40W(P>0.05). Compared with 0W, ESSPRI(oral dryness domain) was decreased in TA and NS groups at 8W, 16W and 24W and 32W(P<0.05). The SWS and SPF of the TA group at 16W, 24W and 32W were higher than those of the control group(P<0.05). The CDOS in the NS group at 8W, 24W, and 32W were lower than those of the control group(P<0.05). Conclusion TA and NS irrigation of the major salivary glands can continuously relieve xerostomia in SS patients for 32 weeks.

Objective To investigate the displacement trend of maxillary first molar and the stress of periodontal tissue when the screw split-base appliance was moved 0.2 mm away from the maxillary first molar. Methods Cone-beam CT (CBCT) was used to scan volunteers’ maxillofacial oral conditions. Mimics 20.0 software was introduced to process the CBCT data. Geometric and physical modeling was performed using Geomagic Studio 2014 reverse engineering software and NX 1911 software. The model of maxilla-upper dentition-periodontal membrane-mucperiosteum-screw split-base appliance was established. The finite element software Ansys Workbench 2019 was used to move the model of screw split-base appliance to the maxillary first molar by 0.2 mm. The displacement trend, stress size and stress distribution of periodontal membrane of maxillary first molar were discussed. Results ①The single displacement of distal movement of maxillary first molar with screw splint-based appliance was large, and the teeth tended to move obliquely. ②When the appliance was used to remove the maxillary first molar, the stress was mainly distributed on the maxillary first molar and the maximum of the equivalent stress was located at the root bifurcation of the distal buccal root of the first molar. Conclusion The screw split-base appliance is recommended for the treatment of first molar with fully developed roots and mesial inclination of the first molar.

Objective To investigate the morphological differences of localized dentition and mandible between patients with mesio-impacted mandibular second molars(MM2) and non-impacted patients in three dimensions and analyze the morphological characteristics. Methods A total of 148 patients who underwent cone-beam computed tomography(CBCT) were included and divided into three groups. Group 1(G1) included 50 patients with unilaterally mesio-impacted MM2; group 2(G2) was composed of 48 patients with bilaterally mesio-impacted MM2, and group 3(G3) was made up of 50 age- and gender-matched controls. Fifteen measurements were selected, including 10 dental measurements and 5 bony measurements. Results The length and width of MM2 were significantly higher in G1 and G2 than in G3, while the height of localized mandibular bone was smaller in G1 and G2. The length and width of localized mandibular bone were statistically smaller in patients with bilaterally impacted MM2 than those with unilaterally impacted MM2. The length and height of localized mandibular bone on unilaterally impacted side were smaller than those on the non-impacted side(P<0.05). Conclusion The crown of MM1 and MM2 were larger in patients with mesio-impacted MM2. The eruption space of MM2 was insufficient, and the space in bilaterally impacted area was narrower than in unilaterally impacted area. Besides, the presence of the mandibular third molar and gender were not significantly associated with mesial impaction of the mandibular second molar.

Objective To evaluate clinical effects of laryngeal mask airway (LMA) on impacted tooth extraction in the anterior maxillary region of children. Methods A total of 116 children were randomly divided into laryngeal mask group (L group, n=58) and endotracheal intubation group (T group, n=58). Blood pressure and heart rates were recorded before induction of anesthesia(T0), before laryngeal mask/tracheal intubation(T1), and after laryngeal mask/endotracheal intubation inserting(T2). We also recorded the time of extubation, the incidence of coughing and agitation during extubation and the incidence of sore throat and fever after surgery. Results At T2, systolic pressure(SP)、diastolic pressure(DP)and heart rate(HR)increased significantly in the T group (P<0.05). In L group, SP, HR at T2 increased significantly compared to T1 (P<0.05), but no significant difference was shown for DP (P>0.05). In T group, SP, DP, HR were all increased at T2 compared to T1 in L group (P<0.05). The blood pressure and heart rate of T2 in T group increased significantly compared with T1; at the same time, it also increased significantly compared with T2 in L group(P<0.05). The extubation time, the incidence of coughing and agitation during extubation in L group was significantly reduced compared with those in T group(P<0.05). Also, the incidence of postoperative sore throat decreased significantly compared with the T group(P<0.05). Conclusion Using LMA in the extraction of impacted teeth in the maxillary anterior region of children, is more conducive to maintaining hemodynamic stability during anesthesia and can significantly reduce the occurrence of adverse reactions during extubation and after surgery in children.

Objective To study the effect of restoration on posterior occlusal function using fixed partial denture assisted by mandibular movement analyzer. Methods In this study, 16 cases with 39 abutments were selected with unilateral terminal occlusal dissociation at more than 2 dental positions. Effects of fixed posterior partial denture were compared between the traditional technology and digital intraoral scanning & mandibular movement analyzer & virtual articulator system & CAD/CAM technology. The occlusal functions of the two groups were compared by articulating paper imprinting, occlusal adjustment time and T-Scan Ⅲ digital occlusal analyzer. Results ①There were significant differences in the early contact point and occlusal adjustment time of the occlusal surface between the two groups(P<0.01). ②After the adjustment of the two groups of prostheses, both posterior teeth occluded evenly, and no obvious early contact points were found. Conclusion The fixed prosthesis made with the aid of mandibular movement analyzer can more accurately restore the occlusal function of patients. Using mandibular movement analyzer reduces occlusal adjustment time, and helps reduce the medical cost. It provides theoretical and data reference for accurately restoring the occlusal function of fixed posterior dental prosthesis.

Renal clear cell carcinoma is a common tumor of the urinary system with high metastatic potential. It often hematogenously spreads through the renal vein and inferior vena cava, and the most common sites of metastasis are lung, bone, and liver. Clear cell carcinoma of the kidney that metastasizes to the parotid gland is rare. One case of renal clear cell carcinoma metastasized to the parotid gland is reported and discussed in combination with relevant literature, which provides experience and reference for the diagnosis and treatment of similar difficult clinical cases.

Fibrous dysplasia (FD)is a rare bone disease in which fibrous tissue replaces bone tissue, and is caused by a GNAS mutation in skeletal stem cells.Currently, there is no cure for FD. Receptor activator for nuclear factor-κB ligand (RANKL)has been discovered to be highly expressed in FD lesions, which mediates osteoclast hyperfunction and causes pathological bone fractures in severe cases. RANKL is thus a possible therapeutic target for FD. RANKL inhibition in FD treatment draws attention from researchers at home and abroad. Clinical case studies and laboratory studies have validated the relieving effect of RANKL inhibition on skeletal symptoms of FD. The current progress of RANKL inhibition in the management of FD is reviewed in this article.

Root resorption induced by orthodontics, a common and severe complication of orthodontic treatment, is often described as orthodontically induced inflammatory root resorption(OIIRR). Orthodontic root resorption can occur at any time during orthodontic treatment and results in poor dental prognosis and reduced stability of effects. Therefore, it is an essential skill for orthodontists to predict the susceptibility of patients to root resorption in clinical practice, to avoid risk factors that may trigger root resorption, and to use appropriate treatment. In this article, based on the latest clinical and basic research advances, the risk factors for orthodontically induced inflammatory root resorption will be categorized and reviewed to provide reference for orthodontic practice.

Le Fort Ⅰ osteotomy is commonly used for correction and treatment of maxillofacial deformities by re-positioning the maxilla. However, Le Fort Ⅰ surgery may lead to surgical soft tissue alterations in nasal morphology, which should be predicted and explained to the patient. It has been reported that the adverse change of nasal morphology after orthognathic surgery is one of the main reasons of decreased patient’s satisfaction. Therefore, understanding such changes is vital for surgical planning and for obtaining appropriate informed consent. In this paper, we reviewed the progress in studieson morphological changes in the nose after Le Fort Ⅰ osteotomy in order to provide reference for clinical practice.

The analysis of maxillofacial soft tissue is closely related to the aesthetic effect and stability of orthodontic treatment. Three dimensional stereophotogrammetry is an important tool for orthodontists to conduct soft tissue analysis. Most of the three-dimensional photogrammetric devices have acceptable accuracy and reproducibility, and are widely used in orthodontic diagnosis, treatment planning, treatment monitoring and postoperative evaluation. With the development of computer technology and the arrival of big data era, the stereophotogrammetry technology has bright prospects in terms of promoting imaging capability, enriching software functions, enhancing user friendliness, developing automation technology and establishing and improving databases.

Maxillary incisors are retracted under the action of orthodontic force, accompanied by periodontal tissue remodeling. However, large-scale tooth movement or poor control will cause damage to periodontal support tissue and cause complications such as alveolar bone loss. The main influencing factors of alveolar bone remodeling are lip inclination, retraction distance, retraction methods, vertical facial type, sagittal facial type, body factors and soon. There are many studies in this field, but there is a lack of unified understanding. This paper reviews the reconstruction of labial and palatal alveolar bone and its influencing factors during maxillary incisor retraction, so as to provide reference for clinical practice.