Traumatic occlusion is a state of occlusion that causes occlusal trauma. Occlusal abnormality is not always traumatic occlusion, and an apparent normal occlusion may be traumatic occlusion. Due to the lack of a clear diagnostic criteria, traumatic occlusion is a difficult problem in clinical cognition. This article aims to explain the concept of occlusion and propose the concept of occlusal trauma syndrome for the diagnosis of traumatic occlusion.

Objective To analyze the histomorphometry differences of condylar cartilage osteogenesis under altered masticatory loading, and to study the mechanism of masticatory loading on condylar development in growing rabbits. Methods sixteen 15-day-old rabbits were randomly divided into two groups and fed different kinds of food, such as solid diet (n=8) and soft diet (n=8). ALL the growing rabbits were weaned at 28-day-old. Tetracycline (50mg/kg), calcein (20mg/kg) and were given intramuscularly on the 28-day-old and 33-day-old. The rabbits were sacrificed on the 38-day-old. The specimens of condyles were embedded in methylmethacrylate. Undecalcified hard tissue slicings (20mm) were then made and observed with a fluorescence microscope. We measured the cartilage osteogenesis thickness and the histomorphometry parameters of the condyle in two groups and did statistical analysis. Results The statistical analysis showed that there was significant difference in the cartilage osteogenesis thickness, percent trabecular area, trabecular number, trabecular thickness and trabecular separation in the two groups (P<0.05). The solid diet groups exceeded those of the soft diet groups except trabecular separation. The mineral appositeion rate of solid diet groups [ (3.25±0.02)μm / d ] was higher than soft diet groups [ (2.37±0.02)μm / d ]. Conclusion The condylar cartilage osteogenesis in growing rabbits soft diet groups was weaker than hard diet groups. Mastication is an important factor which affecting the growth of the condylar cartilage osteogenesis.

To explore the effects of IL-17A to promote proliferation and differentiation of preosteoclasts RAW264.7 cells. Methods: RAW264.7 cells were cultured by RANKL and M-CSF at 24h after treated with IL-17A. CCK-8 kits and RT-PCR were used to evaluate the effects of proliferation and differentiation. Results: IL-17A could promote proliferation of RAW264.7 cells, the proliferation effects of IL-17A had a dose-effect relationship and was in a time-dependent manner; At the concentration of 50ng/ml of IL-17A, the activity of genes including CathK，RANK and NAFTC1 mRNA increased. Conclusion: It is demonstrated that IL-17A mainly promotes RAW264.7 cells proliferation, and promotes RAW264.7 cells differentiation.

Objective:To investigate the effect of autophagy on the proliferation of osteoblasts induced by hypoxia. Methods：Preparation of cell hypoxia model by CoCl2 for LC3was detected by Western blot and immunofluorescence assay; autophagosome was detected by transmission electron microscope; MTT assay and flow cytometrywesr used to detect the effect of autophagy on cell proliferation respectively. Results：The expression of autophagosome double membrane forming protein LC3-II began to increase CoCl2 treatment 3h later, reached the highest value 6h later, and then decreased the expression level. The results of immunofluorescence showed that LC3 protein in cytoplasm was higher than that in the control group. Autophagosomes were detected in experimental group. Compared with the control group, the cell growth was inhibited by CoCl2, reached its peak 12h later, and then the inhibitory ability became weakened. The G1 phase ratio was higher and G2 phase ratio was less than the control group. Conclusion: Hypoxia up-regulates autophagy activity of osteoblasts for inhibiting cell proliferation

[Abstract] PURPOSE: To figure out the effects of psoralen on orthodontic relapse and GPR30. METHODS: 36 Wistar rats were divided into two groups at random, force appliances were removed after 21 days, then two groups were given psoralen and sodium chloride respectively for 28 days. Measured relapse distance every week. Morphology changes were observed by hematoxylin-eosinstaining. The expression of GPR30 was determined by immunohistochemistry staining. RESULTS: Psoralen group showed lower relapse rate in every detected time, but significant difference was witnessed only in day 7 compared to control group. The expression of GPR30 in psoralen group was significantly higher than control group. CONCLUSIONS: GPR30 is expressed in periodontal tissue. Psoralen could increase the expression of GPR30, stimulate bone generation, and inhibit bone resorption.

Objective To explore anesthetic adverse effects (AAEs) related visceral organ lesions in combined diet-induced obese (DIO) and ligation-induced periodontitis (LIP) models. Methods Combined DIO (16-week on diet) and LIP (5- or 10-day ligation) mouse (C57 BL/6J, male) models were studied (n = 120). Following DIO period, LIP was established under anesthesia with 4% w/v chloral hydrate (i.p.), with sham-ligation as the control. Abdominal organ lesions related to AAEs were assessed by general necropsy. Results AAEs-related organ lesions were found in 14.8% (17/115) of the mice. The involved organs included epididymis, visceral adipose tissue, kidney, spleen and liver, which were all lesioned on the same side. Despite no significance, the proportions of organ lesions and adhesion were 1 (18.1% vs. 9.3%, P = 0.31) and 2 (8.3% vs. 2.3%, P = 0.37) times higher, respectively, in DIO mice than those in normal-weight controls and were 1 (19.0% vs. 10.5%, P = 0.31) and 4 (10.3% vs. 1.8%, P = 0.12) times higher, respectively, after 10 days of ligation than those after 5 days of ligation. Conclusions Potential confounding effects of AAEs should be critically assessed when studying the correlation between obesity and periodontitis.

Objective: To investigate the influence of inner crown thickness on the bonding strength of porcelain fused to Co-Cr alloy endocrown by shear strength test method. Methods:32 molar teeth were randomly divided into 4 groups. Co-Cr alloy endocrowns with a thickness of inner crown of 0.3mm, 0.5mm, 0.8mm and 1.0mm were cast respectively, the bonding strength of porcelain-metal was measured by universal testing machine, and the bonding interface was analyzed by scanning electron microscope and energy dispersive spectrometer. Result: The bonding strength of difference thickness of inner crown were 11.34±1.70MPa, 11.55±1.62MPa, 13.42±1.41MPa and 15.21±2.85MPa respectively, analysis of variance showed there was statistically significant difference(P<0.05). Conclusion: The bonding strength of porcelain fused to Co-Cr alloy endocrown varied according to the different thickness of inner crown and the thicker inner crown was recommended to tooth defect with insufficient prosthodontics space.

Abstract：Objective To investigate the effects of ErCr:YSGG Laser Irradiation on microtensile bond strength of two adhesive systems to dentin.Methods: 20 freshly extracted intact human molars were prepared and randomly divided into four groups(n=5): group1 : Cut by laser +adhension with ONE—Step Plus; group2: Cut by traditonal methods +adhension with ONE—Step Plus;group3: Cut by laser +adhension with +Futurabond DC;group4: Cut by traditonal methods + adhension with +Futurabond DC. Then a resin composite buildup was made for each specimen about 10mm, which was sectioned along its long axis to obtain 15 beams(1.0mm×1.0mm) every subgroup for the microtensile bond strength(MTBS) test. Fracture sites were observed using a light microscope. Statistical analysis was performed using one-way ANOVA and Tukey’s tests with the probability level set at α= 0.05.Morphologic structure of the adhesive interfaces was examined by scanning electron microscopy (SEM). Results: Mean bonding strengths（MPa）for each group were16.37±3.46， 17.74±3.92，16.48±2.85，12.37±3.71Mpa. Group4 had the lowest bond strength（P <0.05）. Conclusions:Er,Cr：YSGG laser can improve the effect on bonding between dentin and self-etched resin cement.

Objective　To investigate the expression of OPN (osteopontin) and MMP-3 (matrix metalloproteinase-3) in oral squamous cell carcinoma and their clinical significance and relevance .Methods The immune- unohistochemical method was performed to detect the expression of OPN and MMP-3 in 60 cases of oral squamous cell carcinoma(OSCC) and 30 cases of normal oral mucosal tissues. The relationship between OPN and MMP-3 and clinicopathological parameters of OSCC was analyzed. Results (1)The positive expression rates of OPN and MMP-3 in oral squamous cell carcinoma tissues were 68.0% and 75.0% respectively. The expressions of OPN and MMP-9 in the oral squamous cell carcinoma and the normal groups had statistically significant difference(P＜0.05).(2)The expression rates of OPN and MMP-3 were correlated with clinical stage, histological differentiation and lymph nodes metastasis (P＜0.05).(3)The expressions of OPN and mmp-3 in oral squamous cell carcinoma were positively correlated, and the correlation index of Spearman was 0.269 (P＜0.05). Conclusion OPN and mmp-3 have high expression in oral squamous cell carcinoma, which is closely related to the occurrence and development of oral squamous carcinoma. Their high expression has synergistic effect on the occurrence and development of oral squamous carcinoma, and it is possible to provide basis for early diagnosis, prognosis and targeted therapy for oral squamous carcinoma.

Objective Using clinical observation questionnaires, imaging methods and other detections, to compare marginal bone loss (MBL), mechanical complications and patient satisfaction of mandibular ball cap overdenture supported by narrow neck and regular neck implant. Methods The over denture design for edentulous mandible was to implant two implants, while the upper attachment was no-splint cap structure. All cases were divided into 2 groups: ①26 cases of narrow neck implants (? = 3.3mm) , 52 implants in total; ②28 cases of regular neck implants (?= 4.1 mm), totally 54 implants. The implant surrounding soft tissue (pocket depth, gingival bleeding index, plaque index and dental calculus index), MBL, repair complications, were observed by clinical examination and imaging after implanting denture 6 months, 1 year and 3 years respectively. The patients' degree of satisfaction through questionnaire was also surveyed in these periods. Results In the three-year follow-up period, all of 108 implants did not loosen and fall out. The average values of marginal bone absorption (MBL) for narrow neck and regular neck implant group were (2.1±0.4) mm, (1.4±0.3)mm respectively, the difference was statistically significant. Repair complications of narrow neck implant and regular neck implant groups were 0.26 and 0.27 (per year/per person) respectively. Patient satisfaction of the latter was slightly higher than the former, which had no significant difference. Conclusion The 3-year retrospective study shows that implant diameter may have impact on the edge of bone absorption during the use of two implants categories. Marginal bone absorption in conventional implant neck is less than narrow neck, while mechanical complications and patient satisfaction in both of them have no significant difference.

Abstract: Objective To analyze the changes in different stages of bimaxillary orthognathic surgery in patients with severe Skeletal Class Ⅲ malocclusion, and compare their postoperative stability. Methods 30 patients with severe skeletal Angel Class Ⅲ malocclusion were selected and treated with bimaxillary orthognathic surgeries. SPSS20.0 software package was used to analyze the changes of the hard tissues at the following stages: before treatment(T0); before surgery(T1); 6 weeks after surgery(T2); after treatment(T3). Results Comparing T1 with T0, significant changes occurred in the corresponding measurements of both upper and lower incisors (P<0.05). Comparing T2 with T1, the maxilla moved forward and downward, while the mandible moved backward and upward (P<0.05). The SNA angel, the SNB angel, the ANB angel and Wits appraisal varied significantly(P<0.05). OP-SN increased significantly(P<0.05).The occlusal plane had a counterclockwise rotation(P<0.05). The upper and lower facial height changed significantly(P<0.05) and the vertical facial proportions became more harmonious. All the patients had established good occlusion relationship. Comparing T3 with T2, the landmarks of the maxilla and mandibular had slightly relapsed, but the changes were not statistically significant(P<0.05). Conclusion Bimaxillary surgery can correct maxilla deformity, improve vertical facial proportions, change occlusal plane inclinations, improve the occlusion relationship significantly, and have a good postoperative stability.

Objective To observe the effect of applying osteolysis release and canine rapid movement device in orthodontic treatment of adult extraction. Methods 64 patients with malocclusion treated in our hospital from September 2015 to July 2017 were selected as the subjects. According to the random number table, they were divided into the control group and the study group, 32 cases in each group. The control group was treated with routine orthodontic treatment by exelcymosis, while the study group was treated with orthodontics and canine rapid movement device during orthodontic tooth extraction. The in-place time of the distal movement of the canine teeth, periodontal condition, and root resorption of the canine teeth were observed, and the complications of the two groups were compared. Results In the study group, the in-place time of the distal movement of the canine teeth was significantly shorter than that in the control group. 3 months after treatment, the gingival index (GI), sulcular bleeding index (SBI) and plaque index (PLI) all significantly increased in the two groups (P < 0.05), and there was no significant difference between the study group and the control group (P > 0.05). After the canine teeth were in place, the root resorption volume of the canine teeth in the study group was significantly smaller than that in the control group (P < 0.05); there was no significant difference in the incidence rate of complications between the two groups (P > 0.05). Conclusion In the orthodontic treatment by exelcymosis of adults, the application of osteolysis release and canine rapid movement device in adult tooth extraction can accelerate distal movement of the cuspid and has better safety.

PURPOSE: To investigated the relationship between the capacity of oral samples to produce ammonia from urea and caries experience by measuring urease activity in saliva and dental plaque samples from children. METHODS: Samples of the saliva and dental plaque were collected from 98 subjects between 3 to 6 years old, the oral condition were recorded. The samples were divided into three groups: caries free group, medium caries group and high caries group according to caries statues. Urease activity was determined by testing the ammonia nitrogen concentration of samples of subjects. With SPSS 19.0 software package, variance analysis and correlation analysis were used to determine the relationship of urease activity with dental caries in primary teeth. RESULTS: The amount of ammonia generated from the test substrates by plaque samples between caries free group, medium caries group and high caries group had statistical significance. By correlation analysis, there was positive correlation between caries statue and urease activity. CONCLUSIONS: This study supported the theory that increased caries risk was associated with reduced alkali-generating capacity of the bacteria colonizing the oral cavity; providing compelling evidence to further our understanding of oral alkali-generation in health and disease.

Abstract:The discovery of dental stem cells has received extensive attention because of its significance for the development of novel cellular therapies in dentistry. Dental stem cells are also excellent for studies on cellular processes during dental tissue development or regeneration. Multipotent undifferentiated cells in the dental follicle are one example of dental stem cells, having been used in studies on cellular processes during the differentiation into alveolar osteoblasts and cementoblasts,which are important forperiodontal tissue.This review summarizes current knowledge about the influence of signaling pathways, transcription factors and extracellular matrix proteins on the osteogenic differentiation of DFCs.

Metformin is a biguanide hypoglycemic drug mainly used to treat type 2 diabetes mellitus (T2DM) and metabolic syndrome. However, the potential use of metformin goes far beyond its intended use. In recent years, with more and more studies on metformin, more effects of the drug in different situations have been discovered. In addition to the role of lowering blood sugar, metformin has the effects of anti-tumor, anti-aging, anti-inflammation, modulation of gut microbiota and potential osteogenesis. This article reviews the role of metformin in various fields and provides a reference for clinicians and researchers.

Calcium phosphate cement (CPC) has been used clinically as a bone repair material. As a bioactive ion, silicon has good osteogenic activity and potential to improve the physical and chemical properties of bone cement. Therefore, the way incorporating silicon into calcium phosphate cement gradually become a hot topic in recent years. This article will review the research progress of calcium phosphate cement with silicon.

Root canal therapy (RCT) is the most commonly used and effective method to treat dental pulp disease and periapical disease. However, because of root canal omission and difficult dredge, the treatments of calcified root canals often fail. Clinical diagnosis and evaluation with root canal explorations and radiologia are able to improve the success rate of root canal therapy. Additionally, root canal dredging which makes use of specialize instruments such as ultrasonic microscope, plus chemical reagents can also promote the successful rate. This article will review the research progress on the mechanism, diagnosis, evaluation and pathway establishment of the calcified root canal.

The 5-year and 10-year survival rates of ceramic and composite resin inlays and onlays of posterior teeth are 87.1%~97.6% and 51.4%~85.4%, respectively. Their performances are based on several factors of the materials and thickness of restoration, the position and condition of the abutment tooth and the application of cements. Previous clinical investigations showed that the risk of fracture decreased significantly when the thickness of inlays was increased to 2 mm. Currently, self-adhesive resin cements have achieved similar clinical results for cementations of inlays and onlays compared with self-etch and etch-&-rinse resin cements. The application of resin cements and rubber dams can improve the clinical outcome of inlays and onlays. Concerning the materials used for inlay restorations, the positions and conditions of abutment tooth and the selection of cements, the limited data in the present study, a consolidated conclusion can not be drawn.