Abstract: Objective To investigate the effects of BMP2 and BMP4 on the expression of matrix metalloproteinase 20 (MMP20) and kallikrein 4 (KLK4) in ALC (ameloblast-lineage cell). Methods Recombinant proteins of BMP2 and BMP4 were added to ALC cell lines, and changes in BMP pathway signaling and enamel matrix protease expression were detected by Western blot and real-time PCR. At the same time, another group of cells was treated with a BMP pathway inhibitor（Dorsomorphin, Dor）to detect the expression of enamel matrix proteases. Results Under the action of BMP2 and BMP4 proteins, the expression of classical pathway（Smad1/5/8）and non-classical pathway（p38）of BMP pathway in ALC cells was significantly enhanced, and the expression of MMP20 and KLK4 genes was also significantly up-regulated. In the same period, the expression of the classical pathway of BMP pathway in ALC cells with Dorsomorphin was significantly decreased, while the expression of the non-classical pathway was not significantly changed, and the expression of MMP20 and KLK4 genes also showed a significant down-regulation trend. In another set of experiments, the treatment group with BMP inhibitor showed down-regulation of MMP20 and KLK4 protein expression, while the rescue group treated with BMP2 and BMP4 showed significant recovery of MMP20 and KLK4 protein levels. Conclusions BMP2 and BMP4 can regulate the expression of enamel matrix protease during tooth enamel formation by influencing the BMP classical pathway.

Objective To investigate the therapeutic effect of Allicin on oral squamous cell carcinoma by in vitro studies, and to analyze the possible mechanism by network pharmacology. Methods The effects of Allicin on the proliferation, migration and invasion of SCC-15 cells were detected by CCK-8 method, scratch test and Transwell test. According to the 2D and 3D structure of Allicin, the potential target genes of Allicin were predicted. The possible pathogenic genes of OSCC were obtained by GEO chip, and the protein interaction network was constructed. The KEGG pathway and GO function in the enriched network were analyzed by bioinformatics method. Results When the concentration of Allicin was over 200 μmol/L, the proliferation of SCC-15 cells was significantly inhibited, and the inhibition increased with the increase of time and concentration (P<0.01). Among 104 potential target genes of Allicin, 12 genes intersected with oral squamous cell carcinoma target genes. KEGG analysis revealed that the intersection was related to cell cycle, p53 signaling pathway and platinum resistance. Go analysis indicated that intersection had multiple effects on biological process, molecular function and cell components of OSCC cells. Conclusion Allicin may play a therapeutic role in oral squamous cell carcinoma cells by affecting multiple signal pathways through multiple targets.

【 abstract 】 objective: The sealing effect of dentin tubule and anti-brushing ability of different desensitization methods were observed by scanning electron microscope.evaluateing zhe effect of potassium fluoride resin desensitizer, laser and laser combined with potassium fluoride phenolic resin desensitizer.So that providing experimental basis and theoretical support for the clinical application of laser combined with fluoropotassium phenolic resin desensitizer.Methods: 48 caries free third molars were selected and prepared into 3mm*3mm*2.5mm dentin blocks.They were randomly divided into four groups according to different desensitization methods.Group A :control group; Group B :potassium fluoride phenolic resin desensitizer group; Group C :laser group; Group D : laser combined with fluoropolyphenolic resin desensitizer group. In group B/C/D, 6 samples were randomly selected as immediate group and the remaining 6 samples were selected as wear group for the brushing experiment. Half of the dentin specimens were randomly selected to be split in each group to observe the longitudinal profile. The surface closure of the dentinal tubules of the blank group and the test group was observed by scanning electron microscope.The morphological analysis was performed about the representative areas to observe the closure depth of dentin tubules in longitudinal profile. Using SPSS 24.0 analyze all date .Results: 1. Group B, group C and group D could effectively block the dentin surface （p ＜ 0.05）. 2. In pairwise comparison, there was no statistical difference in the depth of closure between the b/d groups（p ＞0.05）, however, both are deeper than group C（p ＜0.05）.3. After brushing tooth, The differences among the three groups in sealing dentin tubule orifice were significant（p ＜ 0.05）. group D was better than groupB and group C, groupB was better than group c （p ＜ 0.05）.4. After brushing tooth ,as the depth of longitudinal section ,group B and group D were deeper than group C （p ＜ 0.05）. Conclusion:1.Fluorine potassium phenolic resin desensitizer ,laser and the combination of laser and fluorine potassium phenolic resin desensitizer can effective seal dentin surface.2.The effect of the combination of laser and potassium fluoropotassium phenolic resin desensitizing on sealing dentinal tubules is better and more durable than that of desensitizing agent or laser alone. The depth of laser-closed dentinal tubules is small, and the ability of mechanical brushing is poor.

Objective To investigate the effects of different adhesives and aging treatments on the bonding strength of two kinds of CAD / CAM all-ceramic materials. Methods The prepared Vita Enamic (experimental group) and Vitablocs Mark II (control group) specimens were randomly divided into groups (60 in each group), and three commonly used resin bonding materials (Panavia F, RelyX Veneer, and RelyX Unicem) were applied respectively. Body teeth (120 in total) were bonded, and they were randomly divided into a thermal-cold cycling group and a 37 ℃ water bath group for aging treatment. Finally, a universal material testing machine was used to test the bonding strength of each group, and statistical analysis was performed. Results 1) The bonding strength between the same kind of adhesive and the corresponding test specimen in the thermal-cold cycling group was lower than that in the 37 ℃ water bath group (P<0.05); 2) Under both conditions of 37 ℃ water bath and thermal-cold cycling, the bonding strength of each adhesive to Vitablocs MarkⅡ and Vita Enamic was Panavia F＞RelyX Veneer＞RelyX Unicem (P＜0.05); 3) The bonding strength of all three adhesives to Vitablocs MarkⅡ was higher than Vita Enamic (p <0.05). Conclusion The thermal-cold cycling aging treatment can reduce the adhesion of three kinds of adhesives to two kinds of porcelain materials. Panavia F can obtain higher bonding strength for CAD / CAM all-ceramic materials. Compared to Vita Enamic, Vitablocs MarkⅡ has higher bonding strength.

Objective To investigate the effectiveness of steam autoclave and hydrogen peroxide plasma sterilization technology (HPPST) on extracted human teeth and the influence of sterilization methods on bond strength of dentin adhesive system. Methods 40 extracted human premolars were collected and divided evenly into two groups randomizely: steam autoclave group and HPPST group. Another 10 freshly extracted teeth without sterilization were used as positive control for the bond strength test. After treated by the two sterilization methods respectively, the effectiveness of sterilizations were determined by agar plate culture. Composite resins were bonded to the dentins by Clearfil SE Bond. Then the bond strength was detected by shear force experiment. Results After treated by the two sterilization methods respectively, all the samples were effectively sterilized determined by agar plate culture. Compared with the freshly extracted teeth (64.37±4.88MPa), the sterilized teeth (47.66±1.22MPa) had significantly lower bond strength with the HPPST group (36.88±2.61MPa) being the lowest. Conclusion Both steam autoclave and hydrogen peroxide plasma sterilization technology were suitable to sterilize extracted human teeth but resulted in significantly lower bond strength.

Objective: To investigate the therapeutic effect of low-level Ga-Al-As laser therapy on temporomandibular joint pain. Methods: Fifty patients with temporomandibular joint pain were divided into laser treatment group (n=25) and control group (n=25) according to the principle of randomization and double blindness. Patients in the laser treatment group were treated with low-level Ga-Al-As laser therapy, and patients in the control group were treated with simulated laser irradiation that emitted the same red indicator light. The irradiation time of both groups was 5 min, and the irradiation was performed once a day for 3 consecutive days. The patient's maximum vertical opening, protrusion excursion, affected side lateral excursion, offside lateral excursion, pressure pain threshold and visual analogue scale were measured before and after each treatment. The corresponding scores were recorded, and analysis of variance of repeated measurements was used for statistical analysis. Results: After laser treatment of low-level Ga-Al-As laser therapy, the mandibular functional movement (P<0.05) and pain symptoms (P=0.001) were significantly improved. Patients in the control group showed no significant difference in mandibular functional movement and pain symptoms compared with those before treatment (P>0.05). Conclusion: Low-level Ga-Al-As laser therapy can effectively alleviate the symptoms of temporomandibular joint pain and improve the mandibular functional movement. The laser has the advantages of short treatment, high efficiency, no pain, no side effects, and has certain clinical application value.

Objective To evaluate postoperative clinical efficacy of root canal therapy for elderly diabetes patients with apical periodontitis. Methods 94 patients who needed root canal therapy were divided into two groups, one group with 47 patients were diabetic while the other group with 47 patients were non-diabetic. Then postoperative pain condition and 6-months clinical efficacy were observed. Results Postoperative pain and 6-months clinical efficacy were no significant difference between diabetic patients and non-diabetic patients (P>0.05); Diabetic patients with good control of blood glucose had higher efficiency than those with poor control (P<0.05). Conclusions With good control of blood glucose, root canal therapy can effectively treat the elderly diabetes patients with apical periodontitis.

Objective　To analyze the clinical and histological results of regenerative endodontic procedures of immature permanent teeth and to evaluate the healing outcomes of regenerative treatment for immature permanent teeth. Methods　MEDLINE and Web of Science databases were used to search and analyze the literatures with histological results of regenerative endodontic procedures of human immature permanent teeth before December 31, 2019. Results　Sixteen literatures were included, all of which were case reports, including 25 teeth. Of the 25 included teeth, 2 failed, 2 reached the primary-goal, 16 reached the secondary goal, and 5 reached the tertiary goal in clinical evaluation. Histological evaluation to 21 teeth reaching secondary goal and tertiary goal, among 19 teeth receiving hard tissue histological examination, only 2 teeth of found typical of dentine structure, and 17 teeth found bone-like, cementum-like or tertiary dentin-like tissue. Among 20 teeth receiving soft tissue histological examination, only 3 teeth found typical odontoblast-like cells. In immunohistochemistry examination of 10 teeth, 5 teeth found nerve regeneration. Conclusions　Immature permanent teeth could achieve the success of clinical examination after regenerative endodontic procedures, but the continued development of the root was the deposition of dentin-like, bone-like and cement-like tissues in the root canal wall, the regain of pulp vitality was due to nerve regeneration.

Objective To systematically evaluate the effect of excess cement on the risk of peri-implant diseases and study how to minimize the excess cement, so as to provide a basis for the prevention and decision making of peri-implant diseases. Methods PubMed, Embase, Cochrane library, CNKI, WanFang, VIP, SinoMed databases were searched for studies on the risk of excess cement and peri-implant diseases. Results The results yielded 101 potentially relevant titles, among which only 13 studies were included, including 1,125 patients. Studies showed that cement excess might be a risk factor of peri-implant diseases, and it should be avoided as much as possible in clinic. Conclusion Excess cement may be a risk indicator of peri-implant diseases. Using cement-retained crowns of implant restoration requires accurate diagnostic method for detection of excess cement in time, and combining it with careful cement technology can minimize excess cement to reduce the risk of peri-implant diseases.

Objective　 To analyze the change of occlusal contacts of patients before and after the wearing clear overlay retainers and explore the effect of clear overlay retainers on the occlusion during orthodontic retention. Methods　 The T-Scan III digital occlusion analysis system was used to collect and analyze the occlusion contacts in maximum intercuspal position of 34 patients. The occlusion data was collected immediately after the end of fixed orthodontic treatment (T0) and after wearing clear overlay retainers for 3 months (T1). The number of occlusal contacts (NOC), the area of occlusal contacts (AOC) and sagittal displacement of the center point of force (COF) before and after wearing clear overlay retainers were compared. Paired t test and wilcoxon rank sum test were utilized in the data analysis. Results　 The patients’ occlusal contacts in maximum intercuspal position changed after wearing clear overlay retainers for 3 months. From the end of fixed orthodontic treatment (T0) to wearing clear overlay retainers for 3 months (T1) ,the total number and area of occlusal contacts decreased significantly (p＜0.05) , while the number and area of anterior dental arch increased (p＜0.05) and posterior dental arch decreased (p＜0.05). The center point of occlusal force was obviously shifted mesially (p＜0.05). Conclusions　 The use of clear overlay retainers changed the occlusion contacts of the patients after fixed orthodontic treatment. After wearing the clear overlay retainers for 3 months, the total occlusal contact in maximum intercuspal position became shallower, in which the posterior occlusal area got shallower and the anterior area got deeper.

Objective To investigate the effects of invisible orthodontic appliance on the oral microenvironment, teeth and periodontal tissue. Methods Ten orthodontic patients（randomly numbered 1-10）who were treated in our hospital during October 2017 to October 2018 were selected as subjects. The Plaque index（PLI）and Gingival index（GI）were collected before treatment（T0）, 4 months after treatment（T1） and 8 months after treatment（T2）. The changes of bacterial diversity in saliva and the amount of bacteria related to dental caries and periodontal diseases were measured by 16S rDNA sequencing. Results There was no significant change in PLI and GI before and after treatment（P＞0.05）. The bacterial diversity in saliva increased during the treatment. The abundance of main bacteria changed, but the composition was relatively stable at phylum level（P > 0.05）. The abundance of Streptococcu, Actinobacillus and Neisseria increased significantly at genus level（P < 0.05）. Conclusion The wearing of the invisible orthodontic appliance has a certain effect on the oral microenvironment and causes changes in the bacterial community. However, no obvious clinical damage has been observed in the short term. It remains to be further studied whether the longer treatment time will cause other changes.

Objective To analyze the clinical effect of nitrous oxide inhalation on extraction of embedded supernumerary teeth, and to provide reference for the subsequent clinical research. Methods a total of 114 children who were admitted to our hospital from January 2016 to February 2018 were selected for extraction of embedded supernumerary teeth. They were randomly divided into two groups: tooth extraction assisted by nitrous oxide inhalation and tooth extraction routine. Then the condition of the children and curative effects were observed. Results Most of the children were able to complete tooth extraction without any anesthesia accident. Nitrous oxide inhalation group could respond correctly according to the instruction and keep respiratory tract unobstructed, shorten the operation time (P < 0.05), and lower Frankle score (P<0.05). Among them, 98.25% children could complete treatment, and have no nausea or vomiting, have clear consciousness after tooth extraction, normal activity unaffected, no excessive sedation or postoperative hospital phenomenon. Conclusion Nitrous oxide inhalation assisted extraction of embedded supernumerary teeth in children is effective, and can significantly reduce clinical anxiety, shorten treatment time, reduce the probability of general anesthesia treatment and improve treatment completion rate and patient satisfaction, which is worthy of clinical application.

Systemic lupus erythematosus (SLE) is a chronic inflammatory disease that is considered to be a classic autoimmune disease. Periodontitis is chronic infection of periodontal tissue that can lead to systemic and local inflammatory responses and destroy periodontal support tissue through an immune response.The clinicopathology of both involves the destruction of connective tissue, and the pathogenesis also involves the abnormal expression and function of T and B cells as well as the expression disorder of cytokines. This article reviews the relationship between periodontitis and systemic lupus erythematosus from the aspects of epidemiology, immunity, genetic and familial factors, bacterial infection and cytokines.

Periodontitis is an inflammatory and infectious disease that occurs in the periodontal support tissue. With the development of periodontal medicine, the correlation between periodontitis and Alzheimer's disease has gradually become a hot topic. Alzheimer's disease is the most common neurological degenerative disease with complicated pathogenesis in the elderly. Clinical studies have found that periodontitis is closely related to Alzheimer's disease. This article will review the two-way relationship between periodontitis and Alzheimer's disease in epidemiology, pathogenesis and treatments.

Dentin hypersensitivity is a temporary and sharp pain caused by external stimulation of exposed dentin, which seriously affects the quality of life of patients. A large number of studies have shown that occlusion of dentin tubules can effectively treat dentin hypersensitivity, but the therapeutic effect of simply blocking dentin tubules is not ideal. In this paper, we introduce three methods to block dentinal tubules and induce remineralization of dentinal tubules, including nano-hydroxyapatite, bioactive glass and Gallic acid / metal ion complex. These methods can not only quickly block the dentinal tubules, but also continue to play a role, so as to better plug the dentinal tubules, which can reduce the pain of patients and is expected to eventually cure dentin hypersensitivity.

Odontoblasts are differentiated from dental pulp stem cells. A large number of experiments have shown that many kinds of biological factors can activate Smad, MAPK, Wnt, Notch signal pathways which affect the differentiation of odontoblasts. The differentiation of odontoblasts is important for the orderly arrangement odontoblasts and the formation of normal dentin. In this paper, we reviewed the research progress of differentiation signaling pathway of odontoblasts.

Runx2 is a specific transcription factor of osteogenic differentiation, which plays an important role in the formation and differentiation of osteoblasts, the formation and activation of osteoclasts. Orthodontic tooth movement(OTM) is a process in which teeth compress or stretch the periodontal ligament after being subjected to a certain orthodontic force, and the periodontal tissue is rebuilt within the physiological limit, and then the tooth movement is achieved.Many scholars are interested in the methods of accelerating orthodontic tooth movement and maintaining orthodontic tooth movement. It is considered that Runx2 plays an important role in periodontal remodeling during orthodontic tooth movement, and its gene expression plays a positive role in orthodontic tooth movement periodontal remodeling. In this paper, the related research results are described.

The formation of enamel white spot lesions (WSLs) is the most common complication of fixed orthodontic treatment, whose prevalence has been reported to be 50%~80%. As an early caries, it severely effects the integrity and aesthetics of the teeth. So, the early diagnose and treatment is very important in preventing WSLs. There are some methods for the treatment of WSLs including plaque removal, usage of antibacterial adhesives, topical application of fluoride and resin infiltration. Studies have shown that the combination of multiple measures can achieve better control of plaque, termination of demineralization, and promotion of enamel remineralization. The purpose of this article is to review the current researches on the prevention and treatment of WSLs, and to provides clinical recommendations for both the orthodontist and the general dentist.

Chewing-side preference is a kind of bad oral habits, it can be caused by many facters, in recent years, they fould that chewing-side preference will change the function of brain facial sensorimotor cortex and the structure of cerebellum , it is also related to handness, footness, eyeness and earness .This article aims to review the association between chewing-side preference and central nervous system.

Halitosis is defined as an unpleasant odour from the oral cavity, and it has become one of the causes that influence sociality and mental health, 90% of which is intra-oral halitosis, and the main odour-forming gases of which are hydrogen sulfide and methyl mercaptan. The lack of balance between the micro-ecology in the oral cavity causes the prevalence of anaerobes, which is currently considered to be blamed for the intra-oral halitosis. In this paper, the microorganisms related to the intra-oral halitosis and the generation mechanism of volatile sulfur compounds (VSC) are summarized, in order to clarify its pathogenesis. Existing research has revealed that various microorganisms in the oral cavity, including periodontal pathogens, S. moorei, streptococcus salivarius，Candida and some other anaerobes are closely associated with the occurrence of halitosis. Deglycosylation of glycoproteins and the degradation of sulfur containing proteins play an important role in the generation mechanism of VSC including hydrogen sulfide and methyl mercaptan. Bacteria plays an important part in these two steps. β-galactosidase of G+ bacteria plays a main role in deglycosylation of glycoproteins. L-cysteine desulfurase of G- bacteria can degrade cysteine into hydrogen sulfide and METase of G- bacteria can degrade methionine into methyl mercaptan. The aim of this review is to provide some ideas for the etiological analysis, diagnosis and treatment of halitosis in the future.