[Abstract] Objective: To investigate the effect of Resolvin E1 (RvE1) on the biological performance of human dental pulp stem cells (hDPSCs) under hydrogen peroxide-induced (H2O2) oxidative stress. Methods: The hDPSCS were isolated and cultured in vitro by enzymatic tissue block method, and the expression of RvE1 receptor ChemR23 in hDPSCs was detected by immunofluorescence staining; hDPSCs were randomly divided into 3 groups, control group, H2O2 group and H2O2+RvE1 group, H2O2 group and H2O2+RvE1 group were pretreated with 200μM H2O2 for 24h to establish a model of cell oxidative stress. After 24h, the control group and H2O2 group continued to use complete culture medium, and the H2O2+RvE1 group continued to use complete medium containing 100nMRvE1. Hematoxylin-eosin(HE) staining and phalloidin staining were used to observe the morphological changes of hDPSCs; cck-8, scratch test and alkaline phosphatase (ALP) staining were used to detect the changes of hDPSCs proliferation, migration and odontogenic differentiation ability. Results: ChemR23 was widely expressed in hDPSCs; Compared with the control group, hDPSCs in the H2O2 group had abnormal morphology and the ability of proliferation, migration, and odontogenic differentiation was significantly decreased (P <0.05). Compared with the H2O2 group, hDPSCs in the H2O2+RvE1 group had significantly enhanced ability of proliferation, migration and odontogenic differentiation(P <0.05). Conclusion: RvE1 promotes the proliferation, migration and odontogenic differentiation of hDPSCs under oxidative stress.

Abstract: Object: To explore the mechanism of ameloblastoma in inhibiting proliferation, osteogenic differentiation and autophagy level of human bone marrow derived mesenchymal stem cells (hBMSCs) to affect bone regeneration. Method: Human ameloblastoma cells (hAMCs) were isolated and identified. The conditional media was collected to culture the hBMSCs. CCK-8 kit was used to detect the hBMSC proliferation, while ALP staining, Alizarin Red staining and Western-blot were applied to investigate the osteogenic differentiation and autophagy status of the hBMSCs. Results: The osteogenic phenotype of hBMSCs were inhibited by hAMC-CM. The markers of osteogenesis and autophagy in hBMSCs were down-regulated, such as Runx2, Osx, ALP, OCN, OPN, Collagen I, ATG5, Beclin and LC3b. Conclusion: hAMCs could affect autophagy status of hBMSCs via their paracrine functions to inhibit osteogenesis.

Objective To observe the changes of intestinal tissue in rats with diabetes associated periodontitis and explore the effect of artesunate (ART) intervention on TNF-α, MMP-9 and Caspase 3 in the intestinal tissue of rats with diabetes associated periodontitis. Methods 32 Sprague-Dawley rats were randomly divided into healthy control group, diabetes group, diabetes associated periodontitis group and ART intervention group. Diabetes and periodontitis models were made and model identification was performed. At the end of the 10th week, each group was treated with intervention. Animals in the ART intervention group were treated with 60 mg/kg ART, and the rest of groups were treated with normal saline. At the end of the 14th week, animals were sacrificed and intestinal tissue samples were harvested. H&E and immunohistochemical staining were processed to detect the expression of TNF-α, MMP-9 and Caspase 3 in intestinal tissue. Results H&E staining showed that compared with the healthy control group, the intestinal epithelial muscle layer of the diabetes group and the diabetes associated periodontitis group was damaged, the mucosa was damaged, the intestinal glands were deformed with lymphocyte infiltration. In the ART intervention group, the intestinal mucosa structure was basically complete, the intestinal glands were arranged neatly, and the lymphocyte infiltration was reduced. The expressions of TNF-α, MMP-9 and Caspase 3 in the diabetes group and the diabetes associated periodontitis group were significantly higher than those in the healthy control group (P<0.05); The expressions of TNF-α, MMP-9 and Caspase 3 in the ART intervention group were significantly reduced (P<0.05). Conclusion Diabetes associated periodontitis could damage the intestinal epithelial tissue. ART could restore intestinal tissue damage by inhibiting the levels of TNF-α, MMP-9 and Caspase 3.

Objective　To investigate the effect of different magnitudes of SMS on the inflammatory cytokines reactions of HPDLSCs and PPDLSCs. Methods　In vitro culture-tensile stimulation models of HPDLSCs and PPDLSCs were established using a Flexcell Tension Unit. SMS was applied on the HPDLSCs and PPDLSCs (the load was set for 6%, 8%, 10%, 12%, 14%, with frequency of 0.1 Hz.) for 12hours. At the same time，the normal control group was established. The secretions of inflammatory cytokines IL-6，IL-8，IL-1β and TNF-α were examined by elisa. Results　The secretion of IL-6, IL-8, IL-1β and TNF-α were higher in PPDLSCs than in HPDLSCs without SMS(P<0.05). When SMS was loaded, the expressions of IL-1β and TNF-α increased a little in PPDLSCs(P<0.05). However, the expression of IL-6 and IL-8 was up regulated to a considerable high level and had a positive correlation with the magnitude of SMS in a certain range in PPDLSCs. Conclusions　The periodontitis microenvironment increased the secretion of inflammatory cytokines of PDLSCs. Under SMS, different inflammatory cytokines were up-regulated by different extents, among which IL-6 and IL-8 were increased considerably, which indicates that IL-6 and IL-8 were involved in the reaction of PDLSCs to SMS in periodontitis microenvironment.

[Abstract] Objective To analyze the morphometric changes on gingival tissue when FAM20A is conditional knock out (cKO) in mice. Methods Brood k14-Cre;Fam20Aflox/flox cKO mice and normal control mice each had 20, at the ages of 4, 6, 8, 12 weeks after birth, be put to death five in each group. Serial paraffin section was cut in a bucco-lingual direction throughout the mandibular first molars, and make haematoxylin and eosin staining. The area of buccal total gingival, gingival epithelial and connective tissue, were measured under optical microscope with the image analysis system. Data were analyzed by two-way analysis of variance of factorial design, and determined the significance level by fisher least significant difference. Results The area of total buccal gingival, gingival epithelium and gingival connective tissue of the cKO mice were all increased significantly than the control group one’s (P < 0.05). Conclusion Loss of epithelial FAM20A in mice causes the area of buccal gingival overgrowth, including gingival epithelial and connective tissue.

Objective To reevaluate the systematic review of root resorption in the orthodontic treatment of clear aligners. Methods To search PubMed, EMBASE, Cochrane Library, Chinese Academic Journal Online Publishing Database, Wanfang database, Chinese biomedical literature database, search the published systematic review of clear aligners, and the time limit is from the establishment of the database to April 2020. Two authors screened and extracted data independently. A measurement tool to access systematic review 2 (AMSTAR2) was used to evaluate each systematic review, and a descriptive study of outcome indicators was used to evaluate the quality of evidence. Results Three systematic reviews were included, including two of high quality and one of medium quality. There were 3 systematic reviews reports on the unified outcome indicators of root resorption degree. The quality of two outcome indicators was high, and the quality of one outcome indicator was medium. Compared with the fixed appliance, the root absorption of the clear aligners decreased. The root absorption of the clear aligner appliance was 0.44mm (SD = 0.12), the root absorption of the fixed appliance was 1.13mm (SD = 0.18), P < 0.05. The standardized mean difference of total teeth was SMD = -0.65, 95% CI [-0.74, - 0.55], P < 0.01; however, the degree of root resorption was also related to the tooth position, the application of light gravity, the design of correction, the degree of patient cooperation and other factors. According to individual systematic reviews, there was no significant difference in root resorption between clear aligner appliance and fixed appliance under individual tooth position and light force condition. Conclusions The results of overview show that the degree of the root resorption of clear aligner is lower than that of fixed appliance. However, the number of studies is small and some of the evidence conflict. The reliability of outcome indicators is general. So clinicians need to have a choice of reference.

Objective To evaluate MSM of the skeletal Class Ⅱ patients aged 10-20 in Jiangsu Province by CBCT before orthodontic treatment, combined with CVM, to provide a reference for the clinical choice of a reasonable RME method. Methods The study subjects included 89 male patients and 120 female patients. MSM were evaluated according to the method of Angelieri, and CVM were evaluated according to the CVM staging method updated and simplified in 2005. Results Age and gender were influencing factors of MSM in 209 patients, MSM of patients aged 16-20 were higher than those aged 10-15 (P<0.01)， MSM in female patients were higher than male (P<0.01)， MSM of CS4-CS6 were higher than that of CS1-CS3 (P<0.01). Gender and CVM were not influencing factors of MSM in patients at 10-15 years old; gender was the influencing factor of MSM in patients at 16-20 years old. Conclusion The results show that orthodontists should evaluate the MSM of skeletal Class Ⅱ patients aged 10-20 years before RME, so as to provide basis for the selection of RME method for patients at 10-15 years old. The influence of gender on 16-20yearold patients should be considered, so as to avoid RME failure caused by excessive tooth effects.

Abstract：　Objective　Through the measurement and analysis of the three-dimensional digital model before and after orthodontic treatment,explore the effect of leveling curve of Spee on the shape of dental arch. Methods　Forty-two patients aged 11 to 13 years old at first diagnosis were selected from the Department of Orthodontics of the Affiliated Stomatological Hospital of Harbin Medical University from 2014 to 2019. According to the depth of the Spee before treatment,the subjects were divided into two groups.Statistical analysis was performed on the measured values before and after treatment in each group.Correlation analysis and regression analysis was done in order to study the related factors of leveling curve of Spee. Results　After the curve of Spee was leveled, the arch width,the arch length and the existing arch length were significantly increased.The deeper the curve of Spee, the more obvious the change.Person correlation analysis showed that the leveling curve of Spee was significantly correlated with the arch width, the arch length and the existing arch length. Conclusions　The levelling curve of Spee will change the shape of the arch,which will increase the width,length and length of the existing arch.The deeper curve of Spee,the more obvious the shape change of the arch.

Abstract: Objective Tooth color is one of the most important concerns for orthodontic patients in pursuing facial aesthetics. The purpose of this study was to evaluate the effect of clear overlay retainers on the color of teeth. Methods Control group: 30 healthy volunteers. Treatment group: 30 patients treated with clear overlay retainers. According to the system of the Commission Internationale de l’Eclairage (lightness, red/green, and yellow/blue)，we measured the color of anterior teeth and premolars of subjects using a spectrophotometer at 0 and 12 months. Results The treatment group included 408 teeth, and control group included 408 teeth. L* decreased, a*, b* increased in the two groups. ΔE control group = 0.80±0.35, ΔE treatment group = 1.53±0.65; In the treatment group, ΔE前牙=1.67±0.67，ΔE前磨牙=1.22±0.47，P<0.01. No effect was found of gender on the color of teeth (P> 0.05). Conclusion Natural tooth has a tendency to darken, turn yellow and turn red; the tooth color of the treatment group changes more.

Using Andrews Six Elements to develop multiple treatment options for adult skeletal class II patients and study the influence of different treatments on facial profile attractiveness. The secondary aim was to assess differences in preference between orthodontists and laypeople. Methods　Input the facial profile photos and lateral cephalometric radiographs of a Chinese woman suffering from skeletal class II to the Dolphin Imaging program.Using Andrews Six Elements to develop orthodontic camouflage treatment,genioplasty with different advancement ranges and orthognathic surgery.The digital images were modified to obtain these treatments comprising 6 profile silhouette by the Dolphin Imaging program and Photoshop software.These images were rated by clinicians and laypersons. Results　Both two groups agreed that the bimaxillary surgery plan based on Andrews Six Elements was the most attractive in profile,the picture with genioplasty (advancement of 8 mm) took the second place. The initial image score of the clinician group was lower than that of the non-professional group, while the image of bimaxillary surgery got higher scores in the clinician group than the non-professional group. Conclusions　For skeletal class II patients with mandibular retrusion,bimaxillary surgery with Andrews six elements is the best treatment to improve the the profile aesthetics.Genioplasty with the most appropriate advancement range can be got by using Andrews Six Elements.There is aesthetics difference between orthodontists and laypeople.

Objective To investigate the prevalence of dental caries among 3 to 5-year-old children in urban area of Nanjing, detect the caries activity Cariostat value and analyze the relationship between Cariostat value and dental caries. Methods 343 children aged 3 to 5 from a kindergarten in Nanjing were examined by a cross-sectional sampling method. The oral condition of children was examined by two specialists and the Cariostat value was determined. Meanwhile, a questionnaire survey was conducted on children's primary caregivers. Results The prevalence in children aged 3 to 5 was 64.43%; the DMFT was 3.71±4.42; the dmfs was 6.72±10.44; the filling rate was 11.16%, and the Cariostat value was 1.98±0.716. There was a significant difference in Cariostat value between the caries group and the caries-free group. The related factors of Cariostat values were feeding mode within six months of birth (OR breastfeeding=2.069), time of using bottle (OR only before two years old=0.626), mother’s daily smoking or passive smoking (ORweekly=4.785), soft scale index (ORno=0.120, ORcovering tooth surface less than 3=0.438), saliva pH value (OR=0.604), and dfms (OR=1.061). Conclusion The prevalence of dental caries among 3 to 5-year-old children in Nanjing is serious. Therefore, in addition to the treatment of existing dental caries, mother/primary caregivers can also reduce the rate of dental caries by scientific feeding within six months of birth, reducing the time of bottle use, quitting smoking and refusing secondhand smoking.

Plaque control is the central tenet of periodontal therapy. The efficacy of plaque control largely determines the prognosis of periodontitis and peri-implantitis. To enhance the effectiveness, antibiotics are usually applied adjunctively to treat severe periodontitis or prevent infection after periodontal surgery and implantation. However, antibiotics application is restricted by the induction of antibiotic resistance and their low efficiency to kill bacteria in the biofilm. Recently, due to the excellent antibacterial properties and less tendency to induce resistance, silver nanoparticles have been explored as an alternative antibacterial agent and are promising to treat periodontitis and peri-implantitis or prevent infection. Therefore, this review has focused on the advances of silver nanoparticles as potential antibacterial agents for periodontal treatment, including the antibacterial mechanism and its influential factors, cytotoxicity, the potential application in periodontitis and peri-implantitis.

Due to the lack of periodontal ligament, dental implants are more prone to cause occlusal overloading, which leads to dental implant failure. The occlusion designs of dental implants are mainly aimed to avoid occlusal overloading. Measures like a narrowed occlusal table, reduced cusp inclination and a wide freedom (1.0-1.5 mm) in centric relation and maximum intercuspation (MIP) are often taken. A crowntoimplant ratio of 1∶2 is ideal, while 1∶1 is acceptable. Crown height space is 8-12 mm. Implant prostheses with less than 15 mm cantilever are recommended in the mandible, and less than 12 mm in the maxilla. Light occlusion of dental implant is recommended in MIP when an individual missing tooth is restored. And implantprotected occlusion should be suggested when multiple missing teeth are restored. In conclusion, the occlusal scheme of dental implants should be designed according to the number and position of missing teeth, the substance of alveolar bone, parafunctional habits of oral cavity, periodontitis history and so on.

With appropriate three-dimensional implant site and sufficient quantity of soft and hard tissue, the emergence profile of implant prosthesis plays a critical role in soft tissue shaping and its long-term stability. In the implant restoration in the anterior tooth area, good soft tissue morphology around the implant can be obtained by modifying the emergence profile of the provisional implant. This paper will clarify the emergency profile of the implant prosthesis in the aesthetic area and the effect of temporarily adjusting the emergency profile of the provisional restoration on shaping the soft tissue around the implant.

Le Fort Ⅰ osteotomy is a common method for surgical correction of maxillary dysplasia. The shape of the nasolabial area changes after maxillary movements. The adverse effects of Le Fort Ⅰ osteotomy on the morphology of the nasolabial area and the corresponding countermeasures were reviewed in this paper.

Ethanol metabolism is related to oxidative stress, leading to cell changes inflammatory processes such as cell death or cell cycle arrest. Alcohol intake can lead to bone destruction and change the expression of interleukin, metalloproteinase and proinflammatory signal. However, reports about the potential effect of alcohol intake on periodontitis lack consistency, and the mechanism of its effect is even less known. This review summarized the effect of alcohol intake on periodontitis, proposed its possible mechanism and provided ideas for followup research.

Clear aligner (CA) is an irresistible device in the field of orthodontics, and has won the praise of doctors and patients for its unique advantages of beauty and comfort. However, clear aligner still has its shortcomings and is not as good as the traditional fixed oral appliance in many aspects. This paper reviews the expression efficiency of clear aligner from many aspects, thus providing design guide for clinical doctors.

As micro vesicles secreted by cells, exosomes, containing cholesterol, protein and nucleic acid, play an important role in cell communication, tissue damage repair and regeneration. MSCsderived exosomes not only retain the function of MSCs, but also avoid the limitations, risks and ethical issues related to cell transplantation. They may become an effective means of "cellfree therapy", and have broad prospects for medical application. This article summarizes the origin and characteristics of exosomes and their role in tissue damage repair, and focuses on progress of research on exosomes from dental tissuederived stem cells in promoting blood vessel regeneration, immune regulation, and in promoting odontogenic differentiation, bone tissue damage repair, and therapy for neurodegenerative diseases, providing new research strategies for clinical treatment.

Exosomes are natural nanovesicles with a diameter of 40 to 100 nm that can be secreted and taken up by a variety of cells. They carry the endogenous genetic information of the mother cell. As a paracellular secretion pathway, it also plays an important role in plasma membrane exchange and transporting proteins, mRNA and other lifeactive substances, so it can play an important regulatory role in various physiological and pathological processes. In terms of oral tissue regeneration, exosomes can not only trigger pulplike tissue regeneration, but also play a prominent role in periodontal tissue regeneration, angiogenesis, bone regeneration, and neural tissue repair. This article elaborates the research progress of the origin, biological traits, functions, and the application of exosomes in oral tissue repair and regeneration, providing reference basis for further research.