N6-methyladenosine (m6A) is the most prevalent epigenetic modification in eukaryotic mRNAs and involves in multiple biological processes. As a reversible modification, the process m6A counts on three types of proteins: Writers, Erasers and Readers. Recently, emerging evidence elucidates the role of m6A modification in the development of oral tissues and progression of oral diseases. This review summarized the recent papers reporting the research progress of m6A in oral diseases, mainly discussing its regulation of tooth and mandible development, as well as temporomandibular arthritis and mucosal disorders.

Objective:To explore whether bone-marrow mesenchymalstem cell (BMSC) could affect ameloblastoma development and recurrence by promoting the proliferation, migration, invasion of mesenchymal cell-like ameloblastoma cell (M-AMC) via up-regulating their autophagy level. Methods:?M-AMC was isolated and identified through tissue pieces and enzymatic digestion culture. The source of M-AMC was identified by Western Blot. In vitro cell cloning experiments and Flow experiments were also used to determine the expression level of M-AMC self-renewal ability. The migration and invasion ability of M-AMC at 24, 48 and 72h were determined by transwell and laying matrigel matrix gel experiments, and the invasion levels of M-AMC and autophagy were measured by Western Blot. Results: In the M-AMC obtained by primary isolation cultures, the interstitial-derived M-AMC accounts for the main population, and has certain stemness and self-renewal capacity. The number of cells proliferating from co-culture group was significantly higher than control group on day 3 and day 7 (P<0.01). The number of M-AMC migrated and invaded at the three time points of 24,48 and 72 h significantly higher than that of the control group (P<0.01). Invasion ability and autophagy level of M-AMC expression were significantly enhanced after coculture with BMSC (P<0.01). Conclusions:?The paracrine effect of BMSC could promote the proliferation, migration and invasion of M-AMC, and these phenotypes were closely related to the up-regulated autophagy in M-AMC.

Objective:To observe the effects and mechanisms of Porphyromonas gingivalis (P. gingivalis) lipopolysaccharide (LPS) on the formation of vital neutrophil extracellular traps (NETs). Methods:Neutrophils were obtained from peripheral venous blood of healthy individuals by density gradient centrifugation and primed with 25 ng/mL GM-CSF and 0.3 μg/mL P. gingivalis LPS for 35 min. Formation of vital NETs was observed by immunofluorescence staining and extracellular DNA was quantified by a microplate reader. DNA sources were explored by PCR. Quantities of extra- and intracellular P. gingivalis in neutrophils were determined to assay the bactericidal efficiency of vital NETs. Levels of reactive oxygen species (ROS) were detected by flow cytometry. Phosphorylation levels of protein kinase Raf, mitogen-activated extracellular signal-regulated kinase (MEK), and extracellular signal-regulated kinase (ERK) were explored by Western blot. Results:GM-CSF+P. gingivalis LPS stimulation led to the formation of vital NETs and the increased levels of extracellular DNA (P＜0.05), which enhanced bactericidal activity of neutrophils (P＜0.05). In this process, mitochondrial DNA was released instead of nuclear DNA. In addition，levels of ROS, p-Raf, p-MEK and p-ERK were significantly increased in the cells treated with GM-CSF+P. gingivalis LPS compared with negative group (P＜0.05). In addition, DPI, an inhibitor of nicotinamide adenine dinucleotide phosphate (NADPH) oxidase, pretreatment resulted in decreased levels of extracellular DNA and ROS (P＜0.01). Conclusions:GM-CSF+P. gingivalis LPS might contribute to the formation of vital NETs depending on the production of ROS and the phosphorylations of Raf, MEK, ERK, which might contribute to the elimination of P. gingivalis and regulate periodontal inflammatory responses.

Objective:With systemic diseases accompanied by dentin abnormalities as the objective of this study, to generalize the phenotypes of dentin dysplasia (DD) and to complement the phenotypes of syndromic DD. Methods:The first edition of oral diseases list and PubMed database were searched for the reported cases. Then the dentin-related phenotypes were counted and analyzed. Results:By the end of the year 2021, a total of 59 cases of systemic diseases with DD were searched in hyperphosphatemic familial tumoral calcinosis (HFTC) and Ehlers-Danlos syndrome (EDS). In these cases, beside the corresponding systemic symptoms, the phenotypes of dentin abnormalities were pulp volume reduction (55.9%), pulp calcification (50.8%) and root dysplasia (35.6%), which were similar to the phenotypes of DD. However, some dentin abnormalities were different from typical DD, such as tooth discoloration (8.5%) and root elongation (18.6%). Conclusions:Systemic diseases with dentin abnormalities often have characteristic DD, typical or atypical. Dentin abnormalities can serve as an important indicator.

Objective:To investigate the expression and clinicopathological significance of miR-138 and FOXD1 in oral squamous cell carcinoma (OSCC). Methods:Forty-four patients with primary OSCC who underwent radical operation were included. The expression of miR-138 and FOXD1 in tumor tissues and paired normal tissues was detected by real-time fluorescent quantitative polymerase chain reaction (qRT-PCR). Chi-square test and Kaplan-Meier survival analysis were used to analyze the relationship between miR-138 expression and clinicopathological features. The gain-of-function experiments in vitro were performed to elucidate the role of miR-138 in OSCC cell line Cal27 by grouping into miR-NC group and miR-138 mimics group. CCK-8 proliferation test was used to detect cell proliferation, Transwell invasion test was used to detect cell invasion, and the role of miR-138 on the biological behavior of OSCC cells were observed. In addition, bioinformatics predictions were used to investigate the potential target genes of miR-138. The effect of miR-138 on FOXD1 expression was determined by Western blot. After co-transfection of miR-138 mimics and sh-FOXD1, the effects of sh-FOXD1 on the biological behavior of OSCC were detected, and the targeting effect of miR-138 on FOXD1 was verified by dual-luciferase reporter assay. Results:The miR-138 expression was significantly down-regulated in OSCC tissues and cell lines (P<0.05). The miR-138 expression was positive related to primary tumor size, lymph node metastasis, TNM stage and prognosis (P<0.05). Up-regulation of miR-138 expression can significantly inhibit the proliferation and invasion of Cal27 cells, and can reduce the expression of FOXD1 in Cal27 cells (P<0.01). FOXD1 overexpression could partially reverse the proliferation and invasion activity of OSCC cells inhibited by transfecting miR-138 mimics. The dual-luciferase reporter assay showed that overexpression of miR-138 significantly inhibited the luciferase activity in FOXD1-wild type group (P<0.05). However, miR-138 mimics did not change the luciferase activity in FOXD1-mutant group. Conclusions:miR-138 inhibits the proliferation and invasion of OSCC by regulating FOXD1 expression. miR-138-FOXD1 axis may be a potential therapeutic target against OSCC.

Objective:?To evaluate the application effect of the new type of bioceramic root canal sealer C-Root SP on the apical extrusion rate and postobturation pain experience of C-Root SP and iRoot SP after root canal filling. Methods:?A total of 498 teeth referred for root canal treatment with irreversible pulpitis and periapical periodontitis were recruited. Patients were randomly distributed into 4 groups by randomized controlled trial with matched obturation technique: iRoot SP with single-cone technique, iRoot SP with warm vertical compaction technique, C-Root SP with single-cone technique, and C-Root SP with warm vertical compaction technique. Postoperative X-ray film evaluation was used to record the apical extrusion condition of sealers in each group. The postobturation pain experience of 4 groups of patients at 1, 3 and 7 days after root canal filling was recorded by means of return visit and score of visual analog scale (VAS), and the effect of sealers on postobturation pain was analyzed. Results:?The extrusive rate rates of iRoot SP and C-Root SP are 45.5% and 43.3%, respectively. There was no significant difference between the extrusive rate of the two sealers using the same filling technique,(P＞0.05). The overfilling rate of sealants in the teeth with apical lesions was higher than that of the teeth without apical lesions (P＜0.05); The rate of sealer extrusion in iRoot SP and C-Root SP with warm vertical compaction technique was higher than that in single-cone technique (P＜0.05); There was no significant difference in the occurrence and intensity of postoperative pain between the two sealers (P＞0.05); The intensity of postoperative pain in each group was mostly mild pain. Extrusion of the two sealers had no significant effect on postoperative pain (P＞0.05). Conclusions:?There was no significant difference in the rate of sealer extrusion and postoperative pain after root canal filling between C-Root SP and iRoot SP.

Objective: To evaluate changes and correlations of masticatory muscles in class II division 1 malocclusion adult patients after orthodontic treatment by cone beam computed tomography (CBCT). Methods: In total, 60 patients with severe class I (n=30) or class II division 1 (n=30) malocclusion were enrolled. Morphological parameters of CBCT (including ascending mandibular ramus, masseter muscle, medial pterygoid, and lateral pterygoid) of these patients before and after the orthodontic treatment were collected. The changes before and after treatment regarding these parameters were compared. Results: There were significant differences in the width, angle of masseter muscles of class I, and the width, angle, thickness of masseter muscles of class II division 1 (P< 0.05). There were significant differences in the width, thickness, area of medial pterygoid muscles of class I (P< 0.05). There were significant differences in the area of lateral pterygoid muscle in upper level of class I and the thickness, area of lateral pterygoid muscle in upper level of class II division 1 (P< 0.05). Conclusions: There were differences morphological changes of masseter, medial pterygoid, and lateral pterygoid muscles between class I and class II division 1 patients.

Objective:?To study the anatomical characteristics of bone at the edentulous maxillary molar sites in order to provide the basis of the palatal sinus elevation and the implantation with palatal angulation. Methods:?In this study, CBCT data of 500 patients with maxillary molar loss were collected. The minimum thickness of the palatal bone plate, the length of the bone plate applicable for the palatal sinus elevation, the minimum and maximum angle and the length of the bone plate applicable for the implantation with palatal angulation at the edentulous maxillary molar sites were measured and statistically analyzed. Results:?There is no statistically significant difference between the ratio of applicable cases of the palatal sinus elevation in the maxillary first molar region and in the maxillary second molar region (P>0.05). The ratio of applicable cases of the implantation with palatal angulation is 42.13% and 46.19% at the left and right upper first molar missing site respectively along with 29.91% and 33.59% at the left and right upper second molar missing site (P<0.05). The ratio of applicable cases of the implantation with palatal angulation is 42.13% and 46.19% at the left and right upper first molar missing site respectively along with 29.91% and 33.59% at the left and right upper second molar missing site. The implantation angle is （23.7±10.66）°to （32.98±10.20）°at the right maxillary first molar missing site,（23.95±10.48）°to （33.23±11.97）°at the right maxillary second molar missing site,（17.82±10.39）°to （34.36±11.04）°at the left maxillary first molar missing site and（17.87±9.88）°to（35.59±10.81）°at the left maxillary second molar missing site. The ratio of implantation with palatal angulation and the minimum implantation angle between the first molar and the second molar were statistically different (P<0.05). No difference was observed on the left and right sides of the same dental position (P>0.05). Conclusions:?Through CBCT imaging measurements and analyses, as for patients with maxillary molars missing, some can choose the implantations with palatal angulation and some who need lateral sinus elevations can choose the palatal approach sinus elevations to fulfill implant restorations.

Bone Marrow Stromal Cells (BMSCs) are a kind of multifunctional stem cells with multi-directional differentiation potential. BMSCs-based bone tissue engineering technology is currently a new method for the treatment of bone defects. Nowadays, the studies on BMSCs mainly focused on those isolated from bones of trunk and appendicular skeleton. However, many comparative studies showed that BMSCs from the craniofacial skeleton display specificities in phenotype and function. Therefore, jaw bone BMSCs may be more suitable for bone tissue engineering technology.

Schwann cells (SCs) are an important type of peripheral nerve cell and studies have shown that peripheral nerve tissue cells such as SCs have an important regulatory role in bone tissue metabolism.By affecting Wnt, MAPK, Hippo and other signaling pathways, exosomes of Schwann cell origin may promote osteogenic differentiation of bone marrow stromal stem cells and others, and participate in the regulation of bone metabolic homeostasis in vivo. Focusing on the role of exosomes of Schwann cell origin in osteogenic differentiation and its mechanism may provide reference data and research directions for future studies on bone regeneration mechanisms, promotion of bone regeneration and exploration of new therapeutic means for jaw bone defect repair.

Mesenchymal stem cells (MSCs) have multi-directional differentiation potential, and their osteogenic differentiation potential plays an important role in bone tissue engineering. Long non-coding RNAs (lncRNAs) can regulate cell cycle, proliferation, metastasis, immunity and differentiation. In recent years, in-depth studies on lncRNAs have revealed that some lncRNAs regulate the osteogenic differentiation of MSCS. This article reviews the lncRNAs involved in the regulation of osteogenic differentiation of MSCs and their roles and regulatory mechanisms.

As a chemical crosslinking agent, carbodiimide can significantly enhance dentine bond strength and durability by enhancing collagen properties and inhibiting the activity of matrix metalloproteinases.?At present, carbon diimide is often used in combination with N-hydroxysuccinimide to achieve better dentine bonding effect.?Therefore, this article reviews the mechanism and combination of carbon diimine to enhance dentine bonding.

As a potential biodegradable material, magnesium based biomaterials have good mechanical strength, potential biocompatibility, biodegradability, bone conductivity and other characteristics, which has become a research hotspot in the field of biomedical materials. However, the rapid degradation of these materials in the physiological environment may lead the loss of mechanical strength, subcutaneous emphysema and alkalosis, thus hindering their clinical application. In view of the above shortcomings, many surface treatment strategies have been proposed to inhibit its degradation rate and enhance its biological activity,biocompatibility and other related properties. In this paper, the research has reviewed the progress of functionalized coatings on the surface of magnesium based biomaterials and their performance in regulating degradation behavior and biological function in recent years .As a potential biodegradable material, magnesium based biomaterials have good mechanical strength, potential biocompatibility, biodegradability, bone conductivity and other characteristics, which has become a research hotspot in the field of biomedical materials. However, the rapid degradation of these materials in the physiological environment may lead the loss of mechanical strength, subcutaneous emphysema and alkalosis, thus hindering their clinical application. In view of the above shortcomings, many surface treatment strategies have been proposed to inhibit its degradation rate and enhance its biological activity,biocompatibility and other related properties. In this paper, the research has reviewed the progress of functionalized coatings on the surface of magnesium based biomaterials and their performance in regulating degradation behavior and biological function in recent years .