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Development of β-type Medical Titanium Alloys’ Performance LIU Jianguo, ZHOU Hongbo 2020, 36(6): 501-508.  DOI: 10.13701/j.cnki.kqyxyj.2020.06.001 Abstract ( 438 )   PDF (1370KB) ( 535 )   Compared with traditional α-type medical titanium alloy, β-type medical titanium alloys have been widely applied as implants and maxillofacial bone repairing implants because of their no biotoxicity, good biocompatibility, excellent degradable behavior, and mechanical properties close to the human natural bone. The present paper summarized the development of β-type medical titanium alloys applied in stomatology based on their preparation and deformation technology, mechanical properties, corrosion resistance, biocompatibility, and so on. References | Related Articles | Metrics

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Research Progress of Platelet Concentrates in Promoting Peripheral Nerve Regeneration LIU Chunying, ZHOU Yanmin 2020, 36(6): 509-511.  DOI: 10.13701/j.cnki.kqyxyj.2020.06.002 Abstract ( 258 )   PDF (785KB) ( 307 )   Peripheral nerve injury is a common disease in stomatology, which can cause varying degrees of sensory and motor dysfunctions. In addition, osseoperception plays an important role in the long-term stability of implants. Platelet concentrates contain a large number of growth factors, which can promote and induce the regeneration and repair of peripheral nerves. Therefore, using platelet concentrates to promote the recovery of injured nerves and the regeneration of implant peripheral nerves have become an important research direction. This article reviews the mechanism of peripheral nerve regeneration, the classification of platelet concentrates, and their regeneration effects on peripheral nerve. References | Related Articles | Metrics

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Research Progress on Gellan Gum Composite in the Field of Bone Defect XU Laijun, LI Jiyao 2020, 36(6): 512-515.  DOI: 10.13701/j.cnki.kqyxyj.2020.06.003 Abstract ( 242 )   PDF (808KB) ( 547 )   Gellan gum is a natural polysaccharide, which is characterized by biocompatibility, biodegradability, and similar to extracellular matrix. It has attracted more and more attention in the field of biomaterials. In recent years, in order to meet the application of gellan gum in bone tissue engineering, the gellan gum composite has been greatly improved in antibacterial, plasticity, and osteogenesis. In this paper, the characteristics of gellan gum and its composite applications in the regeneration and repair of bone defects are reviewed. References | Related Articles | Metrics

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Research Progress on Effect of Sagittal Split Ramus Osteotomy on Temporomandibular Joint TU Wenxing, FENG Yunxia 2020, 36(6): 516-518.  DOI: 10.13701/j.cnki.kqyxyj.2020.06.004 Abstract ( 240 )   PDF (786KB) ( 296 )   Patients with malocclusion have abnormal dental dysfunction and abnormal appearance, which even cause psychological problems. The patients are urgent to solve the problem. The treatment of skeletal malocclusion is mainly treated with orthodontic-orthognathic surgery, ie preoperative orthodontic- orthognathic surgery-postoperative orthodontic procedure. Sagittal split ramus osteotomy (SSRO) is a common clinical orthodontic operation which can realize the extension and retrogression of mandibular position. It has been widely used in the treatment of mandibular misalignment. However, as a traumatic surgery, SSRO may affect the structural position, function, and joint symptoms of the temporomandibular joint. Therefore, this paper reviews the research progress of SSRO on TMJ. References | Related Articles | Metrics

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Application of Artificial Intelligence in Oral Medicine HAN Shengwei, HAN Wei 2020, 36(6): 519-522.  DOI: 10.13701/j.cnki.kqyxyj.2020.06.005 Abstract ( 836 )   PDF (799KB) ( 1074 )   With the development of technology, a new era of “artificial intelligence” is coming. Artificial intelligence can assist in medical diagnosis and treatment, and reduce the pressure of data analysis from physicians. Artificial intelligence is gradually changing the traditional diagnosis and treatment model, which is a future direction and trend of medicine. This paper has reviewed the development of artificial intelligence and its latest practice in oral medicine. This article prospects the future application of artificial intelligence in oral medicine. References | Related Articles | Metrics

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Adhesion, Proliferation, and Osteogenic Differentiation of hSCAPs on HAP and PDA-HAP HE Lin, HE Song, WU Xi, YANG Sen 2020, 36(6): 523-527.  DOI: 10.13701/j.cnki.kqyxyj.2020.06.006 Abstract ( 228 )   PDF (1548KB) ( 317 )   Objective: To compare cell adhesion, proliferation, and osteogenic differentiation of hSCAPs on the HAP and PDA-HAP scaffolds. Methods: hSCAPs were extracted by improved tissue block method and cell surface antigens, i.e. STRO-1, CD90, CD146, CD45, and CD34, were identified by flow cytometry. hSCAPs were inoculated on HAP and PDA-HAP, respectively. DAPI and rhodamine phalloidin were used to stain the nucleus and cytoskeleton respectively to observe cell morphology. The cell proliferation was measured by CCK8 after 1, 3, 5, and 7 days. ALP activity and expression of ALP, OCN, and Runx2 were detected after 1, 7, and 14 days. Results: The hSCAPs expressed STRO-1 (+), CD90 (+), CD146 (+), CD45 (-), and CD34 (-). The number of hSCAPs attached to PDA-HAP was more than that on HAP (P<0.001), and the cell area on PDA-HAP was larger and more fully extended than that on HAP. There was no significant difference in toxicity between HAP and P DA-HAP when cultured hSCAPs for 1, 3, 5, and 7 days (P>0.05). There was no significant difference on the ALP activity between two groups on the 1st and 14th day of induction (P>0.05), however, significant difference on the 7th day (P<0.001). By real-time PCR, it was found that the expression of ALP was the same as that of ALP activity; the expressions of Runx2 in PDA-HAP group were higher than those in HAP group on 1, 7, and 14 days (P<0.05); there was no significant difference on the expression of OCN between two groups on the 1st day (P>0.05), however, significant difference on the 7th and 14th day (P< 0.05). Conclusion: PDA-HAP can significantly promote the expression of ALP, Runx2, and OCN, and promote the osteogenic differentiation of hSCAPs. References | Related Articles | Metrics

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Effect of Lentivirus Mediated BMP-2 and VEGF-165 Transfection of Goat Bone Marrow Mesenchymal Stem Cells into Cartilage Differentiation WANG Jing, Tayier·ALIPU, YAO Zhitao, Adilijiang·SAIMAITI, ZHU Xiaoyu, SUN Changhao, Maimaitituxun·TUERDI 2020, 36(6): 528-533.  DOI: 10.13701/j.cnki.kqyxyj.2020.06.007 Abstract ( 209 )   PDF (2579KB) ( 174 )   Objective: To investigate the effect of lentivirus-mediated BMP-2 and VEGF-165 transfection of goat bone marrow mesenchymal stem cells into cartilage differentiation. Methods: The primary goat bone marrow mesenchymal stem cells were cultured by whole bone marrow adherent method. The target gene was transfected and mediated by virus to study the feasibility of goat BMSCs as the gene co-transfer target cell and the biological changes of cells in vitro, such as culture conditions, proliferation, and differentiation into cartilage after transfection. Results: The expression of BMP-2 mRNA in transfected group was not significantly different from that in BMP-2 group, and the same as the expression of VEGF-165mRNA in transfected group to that of VEGF-165 group. The expression of OCN mRNA in Lv-BMP2-VEGF165 transfection group was higher than that in single gene transfection group (P<0.05), and BMP2 and VEGF165 proteins were only highly expressed in Lv-BMP2-VEGF165 group. The expression of OCN protein in Lv-BMP2-VEGF165 group was significantly higher than that in other groups (P<0.01), and the activity of ALP in Lv-BMP2-VEGF165 transfection group was significantly higher than those of other groups. Conclusion: BMP2, VEGF165, and BMP2/VEGF-165 can be successfully transfected into goat bone marrow mesenchymal stem cells and can be stably expressed for a long time. The synergistic effect of BMP2/VEGF-165 could promote the production of ALP and the synthesis of osteocalcin, and induce the cells into cartilage. References | Related Articles | Metrics

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Effect and Mechanism of Enamel Matrix Protein Derivatives on Osteogenic Differentiation of Periodontal Ligament Stem Cells Infected with Porphyromonas Gingivalis WU Yangxuan, XIANG Li, HUANG Zhiqiang, CHU Jinhai 2020, 36(6): 534-538.  DOI: 10.13701/j.cnki.kqyxyj.2020.06.008 Abstract ( 202 )   PDF (1596KB) ( 209 )   Objective: To investigate the effect and mechanism of enamel matrix protein derivatives on osteogenic differentiation of porphyromonas gingivalis-infected periodontal ligament stem cells (PDLSCs). Methods: PDLSCs were digested and passaged after primary culture. The cells of the 3rd-4th generation were divided into groups. The control group was treated routinely and osteoblast differentiated. The infected group was osteoblast differentiated after 24 hours of porphyromonas gingivalis infection. The enamel matrix protein derivative group was osteoblast differentiated after 24 hours of porphyromonas gingivalis infection and added with 25 mg/L, 50 mg/L, and 100 mg/L enamel matrix protein derivatives during differentiation. 100 mg/L enamel matrix protein derivatives+TNF-α group was osteoblast differentiated after 24 hours of porphyromonas gingivalis infection and added with 100 mg/L enamel matrix protein and 10 ng/mL TNF-α derivatives during differentiation. The number of mineralized nodules, ALP activity, and expression of osteogenic marker genes Runx2, OCN, COL-I and signal pathway molecules p65 NF-κB, p-I κB and I κB were detected. Results: The number of mineralized nodules, ALP activity, and the expression of Runx2, OCN, COL-I, and I-κB in 25 mg/L, 50 mg/L and 100 mg/L enamel matrix protein derivatives groups were significantly higher than those in the infected group, while the expression of p65 NF-κB and p-I κB were significantly lower than those in the infected group. The number of mineralized nodules, ALP activity, and the expression of Runx2, OCN, COL-I and I-κB in 100 mg/L enamel matrix protein derivatives+TNF-α group were significantly lower than those in the 100 mg/L enamel matrix protein derivatives group, while the expression of p65 NF-κB and p-I κB were significantly higher than those in the 100 mg/L enamel matrix protein derivatives group. Conclusion: Enamel matrix protein derivatives can promote the osteogenic differentiation of porphyromonas gingivalis infected PDLSCs by inhibiting the NF-κB pathway. References | Related Articles | Metrics

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Effect of Human Platelet Lysate on Osteogenic Differentiation of Dental Pulp Mesenchymal Cells HUO Dongmei, XU Yan, HU Shaoguang, WANG Qingqing, WANG Ronghai 2020, 36(6): 539-543.  DOI: 10.13701/j.cnki.kqyxyj.2020.06.009 Abstract ( 196 )   PDF (4223KB) ( 279 )   Objective: To study the effect of human platelet lysate (HPL) on the in vitro and in vivo osteogenesis of human dental pulp-derived mesenchymal cells (hDPSCs). Methods: The pulp tissues were cultured with 5% HPL and 10% fetal bovine serum (FBS), and the in vitro osteogenic ability of the cells was detected by the alizarin red and ALP staining. Four 8-mm-diameter round bone defects were prepared on the skull of 10 male Japanese white rabbits, and the rabbits were divided into four groups. In group A, the DPSC with 10% FBS was inoculated in the gelatin sponge (GS). In group B, the DPSCs with 5% HPL were inoculated in the GS. Group C was only GS, and group D was blank control. Micro-CT three-dimensional reconstruction and HE staining were used to observe the osteogenic effect 4 and 8 weeks after operation. Results: The results of alizalin red and ALP staining showed that 5%HPL medium significantly promoted the formation of calcium nodules and the expression of ALP in osteogenic differentiation of hPDSCs (P<0.000 1). The imaging results showed that there was a small amount of new bone formation in group A and B at 4 weeks and a large number of new bones at 8 weeks. The osteogenic effect of group C and D was not obvious, and the bone ability of group B was stronger than that of group A. Histologic observation showed that new bone formation was found in group A and B at 4 and 8 weeks, but there was no obvious new bone area in group C and D at 4 and 8 weeks. Conclusion: 5% HPL can be used for the in vitro culture of hDPSCs, and the in vitro and in vivo osteogenic ability of hDPSCs can be improved. References | Related Articles | Metrics

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Effects of Puerarin on Biological Properties of MC3T3-E1 under High Concentration of Glucocorticoid Circumstance CHEN Zhenyu, PAN Yingjing, ZHANG Yan, HE Xi, HUANG Dahong 2020, 36(6): 544-547.  DOI: 10.13701/j.cnki.kqyxyj.2020.06.010 Abstract ( 191 )   PDF (2709KB) ( 148 )   Objective: To investigate the effect of puerarin on the biological properties of MC3T3-E1 under high concentration of glucocorticoid circumstance through in vitro cell culture and related interventions. Methods: MC3T3-E1 preosteoblasts were cultured in vitro and divide into control group and five experimental groups, which were intervened with gradient concentration of puerarin (0, 10-5, 10-6, 10-7, 10-8, 10-9mol/L) under high concentration of glucocorticoid circumstance (10-6mmol/L). Cell proliferation was detected after 1 d, 4 d, and 7 d of cell culture by using the CCK-8 kit, activity of ALP was detected after 1 d, 4 d, and 7 d of cell culture by using alkaline phosphatase kit, and the expression of OPG mRNA was detected by quantitative real-time PCR after 7 d of cell culturing. The cells were stained with phalloidin after 24 h of culture and observed the cytoskeletal morphology changes under the confocal laser microscope. Results: CCK-8 showed that the difference between the control group and the experimental group was statistically significant (P<0.05), and the most obvious effect of cell proliferation was 10-7mol/L group on the 4th day (P<0.05). ALP activity test showed that the expression of ALP in all the experimental groups increased at the same time and there was statistical significance in the difference between the experimental group and the control group (P<0.05). The results of confocal laser scanning indicated that, in group of 10-7mol/L, the cells spread more widely and the structure was clear. PCR results showed that the expression of OPG mRNA in each experimental group was higher than that in the control group (P<0.05). Conclusion: Puerarin, under high concentration of glucocorticoid circumstance, can promote cell proliferation, extension, and differentiation of MC3T3-E1 cells. References | Related Articles | Metrics

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Effect of Static Magnetic Field on Mandibular Fracture Healing in Rats LIU Yang, LI Shanchang, WANG Changzhen, ZHOU Hongmei, DONG Guofu, ZHAO Xuelong, LIU Qi 2020, 36(6): 548-553.  DOI: 10.13701/j.cnki.kqyxyj.2020.06.011 Abstract ( 180 )   PDF (4311KB) ( 227 )   Objective: To study the effect of static magnetic field on the healing process of mandibular fracture in rats. Methods: 60 SD rats were randomly divided into three groups: fracture operation (group C), fracture operation + fracture covered ceramic (group S), fracture surgery + neodymium magnet with 0.1T covering magnetic field at fracture site (Group L). The body weight, diet, and drinking water of SD rats were investigated every week after operation, and the samples were taken after 2, 4, 6, and 8 weeks. Bone fracture healing was observed by X-ray examination. Expression of BMP-2 and IL-1 in serum was detected by ELISA. Serum calcium was determined by arsenazo Ⅲ method. Fracture area was observed by HE staining. Osteogenesis related genes BMP-2, OPG, and OCN were immunohistochemical detected. Results: X-ray results showed that group L had the best effect of fracture healing, the expressions of BMP-2, IL-1, and calcium in group L were higher than those in group S and C. HE staining showed that the number of new bone trabeculae in group L was significantly more than that in group C and group S. Immunohistochemical results showed that magnetostatic field could promote the synthesis and secretion of BMP-2, OPG, and OCN. Conclusion: Static magnetic field can effectively promote fracture healing. References | Related Articles | Metrics

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A Retrospective Study of Tooth Extraction in Anticoagulant Patients with Low Molecular Weight Heparin Bridging or Maintenance of Anticoagulation ZHU Lijun, LI Jun, WANG Shuqin, JIANG Sui, WANG Qipeng, FENG Hang 2020, 36(6): 554-557.  DOI: 10.13701/j.cnki.kqyxyj.2020.06.012 Abstract ( 219 )   PDF (787KB) ( 256 )   Objective: To evaluate the differences of bleeding and thromboembolic complications after tooth extraction in long-term anticoagulant patients with maintenance of anticoagulation or low molecular weight heparin bridging. Methods: A total of 215 anticoagulant patients were included in the study, and 98 patients were included in the maintaining anticoagulant group, with the average preoperative international normalized ratio (INR) of 2.56±0.45. There were 117 patients in the low-molecular weight heparin bridging group, with an INR average of 1.52±0.21 on the day of operation. Each patient had no more than three teeth extracted. Local hemostatic agents (Avitene ©) and suturing of the wound were used in both groups. Results: There were 7 patients (7.14%) in the maintaining anticoagulation group and 5 patients (4.27%) in the low-molecular weight heparin bridging group who had mild to moderate postoperative bleeding (P=0.361). Patients with mild bleeding were controlled by local compression and local hemostatic agents. For patients with uncontrolled bleeding, vitamin K could be injected or fresh frozen plasma could be infused. None of the participants in either group experienced thromboembolic complications within a month after operation. Conclusion: For patients received anticoagulant therapy with simple tooth extraction, there is no obvious difference in the incidence of postoperative bleeding and postoperative thromboembolic events on maintaining anticoagulation and low molecular heparin bridge. In view of the consequences of thromboembolic complications, such patients can safely keep anticoagulant therapy and no need for low molecular heparin bridging therapy during tooth extraction. References | Related Articles | Metrics

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Clinical Analysis and Treatment of Solitary Fibrous Tumors in Oral and Maxillofacial Region WANG Dani, SUN Guowen, TIAN Mei, CHEN Haoliang, ZHAI Yiwei, ZHANG Lei 2020, 36(6): 558-562.  DOI: 10.13701/j.cnki.kqyxyj.2020.06.013 Abstract ( 182 )   PDF (5550KB) ( 150 )   Objective: To improve the level of clinical diagnosis and treatment by retrospective analyzing the clinical cases of solitary fibrous tumor in oral and maxillofacial region. Methods: A retrospective analysis was conducted on the maxillofacial solitary fibroma, which was included in the pathological database of Nanjing Stomatological Hospital affiliated to Nanjing University from June 2015 to June 2019. The clinical data, imaging data, pathological data, treatment methods, and follow-up data of the patients were analyzed. Results: A total of 8 patients were diagnosed as solitary fibrous tumor in oral and maxillofacial region by postoperative pathology. Of the 2 patients whose postoperative pathology was low grade malignant tumor, 1 had recurrence in other hospital, but no recurrence was found in our hospital at present, and 1 patient had recurrence in postoperative follow-up. Conclusion: Complete resection is the first choice for the treatment of solitary fibroma of maxillofacial region. When it is found that solitary fibroma of the maxillofacial area is prone to soft tissue masses and the imaging enhancement is obvious, the possibility of solitary fibroma should be considered, and the final diagnosis should rely on pathological and immunohistochemical examination. Clinically, patients should be alerted to the invasive or malignant solitary fibroma of the maxillofacial region. Patients should be followed up closely after surgery, and timely surgery should be carried out if recurrence exists. References | Related Articles | Metrics

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Mandibular Impacted Wisdom Teeth Displaced into Sublingual Space: Report of 8 Cases WEI Yunpeng, ZHAO Sufeng 2020, 36(6): 563-566.  DOI: 10.13701/j.cnki.kqyxyj.2020.06.014 Abstract ( 353 )   PDF (2911KB) ( 377 )   Objective: To review the therapeutic methods of the displaced mandibular impacted wisdom teeth. Methods: 8 cases of displaced teeth during the extraction of third molars from January 2014 to April 2019 were reviewed. Bimanual palpation and image examination were used to locate the displaced teeth. Relaxation incisions were made distally and medially of the extraction sockets under local anesthesia, then mucoperiosteal flaps were raised to retrieve the teeth. Results: 8 displaced teeth were successfully managed. 3 months later, the wound healed well and the post-operative recovery was uneventful. Conclusion: Through bimanual palpation and image examination, relaxation incisions at the distal and mesial sides of the extraction sockets were useful to retrieve the displaced teeth References | Related Articles | Metrics

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A Study on Glucose-sensitive Hydrogel in the Treatment of Periodontitis in Diabetic Rats LIU Junyu, XIAO Yu, WANG Xiangyu, LIU Yan, LI Yufang, LIU Haifeng, CHEN Yu, BAO Chongyun 2020, 36(6): 567-571.  DOI: 10.13701/j.cnki.kqyxyj.2020.06.015 Abstract ( 219 )   PDF (3751KB) ( 274 )   Objective: To prepare glucose-sensitive controlled-release hydrogel for the treatment of periodontitis in diabetic rats models. Methods: Chitosan was used as matrix material to prepare hydrogel. Glucose oxidase was immobilized on the hydrogel to prepare glucose sensitive hydrogel, which was characterized by stability test and cell adhesion test. Metronidazole-loaded hydrogel was immersed in dynamic changing concentration of glucose solution. Drug release test was used to test its ability to respond to blood glucose. Finally, Hydrogel was put into the experimental periodontal pocket of diabetic rats to observe its therapeutic effects. Results: The photo-crosslinked hydrogel had stable mechanical properties and facilitated the adherence of osteoblasts MC3T3-E1. After glucose oxidase was immobilized on the surface of the hydrogel, metronidazole release was changed with different concentration of glucose. In the in vivo study, the swelling and bleeding of periodontal tissue were alleviated. Conclusion: A novel glucose sensitive hydrogel drug delivery system is prepared in this study, which provides a promising method for the treatment of diabetic periodontitis. References | Related Articles | Metrics

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Effect of Tobacco Extract Coenzyme Q10 on Immunologic Balance of Treg/T17 Cells in Mice with Periodontitis WU Yunfei, ZHANG Li, ZHANG Xufeng, FU Qiya 2020, 36(6): 572-576.  DOI: 10.13701/j.cnki.kqyxyj.2020.06.016 Abstract ( 184 )   PDF (2547KB) ( 184 )   Objective: To investigate the effect of tobacco extract coenzyme Q10 (CoQ10) on the immunologic balance of Treg/T17 cells in mice with periodontitis. Methods: 36 healthy male mice were divided into control group, model group, tinidazole group, CoQ10 low dose group, CoQ10 medium dose group, and CoQ10 high dose group, with 6 rats in each group, and were given gavage for 6 weeks. The mice model of periodontitis was established by ligation. Alveolar bone loss (ABL) value and alveolar bone resorption were measured in mice. Hematoxylin-eosin (HE) staining was used to detect periodontal histological changes in mice. Flow cytometry was used to analyze the proportions of CD4+ T cells, CD4+ Treg cells, and CD4+ T17 cells in peripheral blood mononuclear cells (PBMC) of mice. The levels of serum TGF-β1, IL-10, and IL-17 were detected by ELISA. Results: Compared with the control group, the ABL values of model group, tinidazole group, and various CoQ10 groups were significantly higher (P<0.05). Compared with the model group, the ABL values of tinidazole group and various CoQ10 groups decreased significantly (P<0.05). Compared with the model group, the periodontal ligament fibers in tinidazole group and various CoQ10 groups were arranged neatly, and the inflammatory cell infiltration in connective tissues was reduced. Compared with the control group, the percentages of CD4+ T cells, CD4+ T17 cells, and the level of IL-17A in peripheral blood PBMC of model group mice increased (P<0.05), and the percentage of CD4+ Treg cells and the levels of TGF-β and IL-10 decreased (P<0.05). Compared with model group, the percentage of CD4+ T cells, CD4+ T17 cells, and the level of IL-17A in tinidazole group and CoQ10 groups decreased (P<0.05), and the percentage of CD4+ Treg cells and the levels of TGF-β and IL-10 increased (P<0.05). Conclusion: Tobacco extract CoQ10 can regulate the immune balance of Treg/T17 cells in mice and alleviate periodontitis. References | Related Articles | Metrics

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Clinical Effect of Bioactive Glass Air Polishing on Dentine Hypersensitivity PEI Xiyan, YANG Wen, SUN Feng, WENG Jinlong 2020, 36(6): 577-580.  DOI: 10.13701/j.cnki.kqyxyj.2020.06.017 Abstract ( 254 )   PDF (785KB) ( 231 )   Objective: To determine the efficacy of bioactive glass air polishing on the dentine hypersensitivity. Methods: In the double-blind randomized control study, 11 subjects with periodontal diseases who need supragingival scaling and air polishing were enrolled. The left and right half mouth teeth were divided into test group (bioactive glass air polising) and control group (sodium hydrogen carbonate air polishing). A visual analogue scale (VAS) was used to evaluate the dentin hypersensitivity at baseline, 1 week, and 4 weeks. Results: At baseline, the test group and the control group VAS were 1.8±2.4 and 1.7±1.9. 1 week, the test group decreased to 1.0±1.3, the control group increased to 2.0±1.4 (P>0.05). The patients in test group (0.9±1.4) reported more comfortable experience than the control group (1.0±0.8), However, the difference was not significant (P>0.05). Conclusion: Bioactive glass air polishing showed a trend of reducing dentin hypersensitivity. The patients had more comfortable experience in the treatment. References | Related Articles | Metrics

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Effects of Polishing Methods on Surface Morphology of and Cell Proliferation of Human Gingival Fibroblasts on Two Kinds of Filling Materials SHANG Jiaxin, SU Rui, MA Chong, LI Xinyue 2020, 36(6): 581-584.  DOI: 10.13701/j.cnki.kqyxyj.2020.06.018 Abstract ( 223 )   PDF (2905KB) ( 246 )   Objective: To observe the surface morphology and biocompatibility of the two polished materials. Methods: The specimens were prepared by using resin-modified glass ionomer GC Fuji Ⅱ LC and nano-composite resin 3M FiltekTM Z350 XT. Silicon particles and super-snap polishing system were used for polishing. The surface morphology of the materials and the root slices were observed by SEM. Human gingival fibroblasts were inoculated on the specimens, and cell proliferation test was conducted by MTT method on the 1st, 3rd, 5th and 7th day. Results: Under 5000 times electron microscope, the surface of resin was smoother than that of glass ionomer, and the surface of resin combined polishing system or silicon particle was smoother than that of glass ion combined polishing system or silicon particle. In the cell proliferation test, the 5d resin combined with super-snap had higher absorbance values than both glassy ion combined with silicon particles and super-snap, and the resin combined with silicon particles had higher absorbance values than glassy ion combined with silicon particles (P<0.05). Conclusion: 3M FiltekTM Z350 XT resin combined with super-snap polishing system can obtain a smoother surface, and the super-snap polishing system can obtain better cell compatibility than the silicon particle polishing treatment. References | Related Articles | Metrics

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Preparation and Performance of Superhydrophobic Gel Nano-coating on Enamel Surface JIN Xiaoting, SHI Shi, CHEN Huanhuan, XUE Dong, MA Jianfeng 2020, 36(6): 585-590.  DOI: 10.13701/j.cnki.kqyxyj.2020.06.019 Abstract ( 233 )   PDF (2661KB) ( 232 )   Objective: To investigate the preparation and performance of superhydrophobic gel nano-coating on enamel surface. Methods: A sol-gel method was used to prepare a trimethylsilyl-modified dopamine-silicone gel (DSTM) superhydrophobic coating. Several 4 mm × 4 mm × 2 mm enamel blocks of bovine tooth were randomly divided into two groups: the experimental group and the control group, which were treated separately by DSTM and deionized water. The effect of coating superhydrophobicity was evaluated by the contact angle. Scanning electron microscope (SEM), Fourier transform infrared spectroscopy (FT-IR), and X-ray photoelectron spectroscopy (XPS) were used to assess the microstructure of the coating surface and analyze the composition of the tooth surface coating. The cell toxicity and biological safety were tested by CCK-8 colorimetry. In order to evaluate the stability of the hydrophobic coating in the oral environment, the coated enamel mass was immersed in artificial saliva at 37 ℃ for 2 h, 4 h, 6 h, 10 h, and 12 h and then observed the contact angle and surface microstructure changes. Results: The contact angle of dental tablets was (60.20±4.56)°, while that of the experimental group was (153.88±2.81)° (P<0.05). Under the SEM observation, the coating surface was composed of interconnected micrometers and nanopores that form a three-dimensional nano-network structure. The XPS and FT-IR showed that the DSTM coating on the tooth surface was successfully prepared. Among the detection values at 24 h, 48 h, and 72 h, the OD values of all groups were comparable to the blank group values. The results of the coating stability experiment showed that the sample still had superhydrophobic properties with a contact angle value of (149.40±2.43)° after being soaked in artificial saliva for 12 h. However, there was no significant changes in the micro-morphology of the micropores and micro-nano structures from the SEM of the saliva-treated coating. Conclusion: In this experiment, a DSTM gel coating was successfully prepared by the sol-gel method. The coating with good biological safety and hydrophobicity has certain stability in a 37 ℃ artificial saliva environment, which provided a basis for the new anti-caries materials. References | Related Articles | Metrics

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Preparation of Yolk Antibody Sustained-release Nano-hydroxyapatite and Its Antibacterial Properties WANG Tengfei, XU Yan, XU Hanying, HAN Xu, SHEN Jilong, CHENG Ting 2020, 36(6): 591-594.  DOI: 10.13701/j.cnki.kqyxyj.2020.06.020 Abstract ( 200 )   PDF (1302KB) ( 165 )   Objective: To prepare nano-hydroxyapatite composite with the sustained release function of egg yolk antibody and test in vitro antibacterial properties. Methods: The morphology and particle size of nano-hydroxyapatite (nano-hydroxyapatite, NHA) were observed by scanning electron microscopy (SEM). The nano-hydroxyapatite was loaded with the anti-porphyromonas gingivalis (anti-P. gingival-IgY) and the drug release behavior of the IgY-NHA composite was studied. Porphyromonas gingival (Pg) was selected as the experimental strain to study the minimal inhibitory concentration (MIC) of IgY-NHA composite. The growth inhibitory effect of IgY-NHA composite on P.gingival was studied to evaluate the antibacterial properties of delayed release of IgY nano-hydroxyapatite. Results: NHA was a porous structure composed of granular nanostructures. With the increase of loading concentration of IgY, the adsorption capacity of NHA increased significantly. When the loading concentration of IgY was 4 g/L, the adsorption capacity was 653 mg/g. Within 36 h, IgY protein was released slowly and continuously. The final release percentage was 34%, the minimum inhibitory concentration of IgY-NHA to P.gingival was 6 g/L. IgY-NHA could delay the time point of P.gingival entering the logarithmic growth period and inhibit P.gingival growth, which was concentration dependent. Conclusion: Nano-hydroxyapatite has good adsorption and sustained-release properties for yolk antibody, and IgY-NHA can inhibit the proliferation of P. gingival. References | Related Articles | Metrics

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Effect of Masking Treatment on Structure Surface on Adhesion Properties between Zirconia and Resin GAO Nan, WEI Yuhe, JIANG Xiao, LU Wei 2020, 36(6): 595-598.  DOI: 10.13701/j.cnki.kqyxyj.2020.06.021 Abstract ( 191 )   PDF (1524KB) ( 216 )   Objective: To investigate the effect of masking treatment on the adhesion between zirconia ceramics and resin. Methods: Zirconia specimens were made and randomly divided into 3 groups: control group, immersion dyeing group, and immersion dyeing masking group. Each group was randomly divided into 2 subgroups, with or without silane coupling agent. The contact angles of specimens were tested. The specimens were bonded with the resin cement. The shear bond strength was tested after 24 hours and the interface fracture mode was observed. Results: There was no statistical difference in contact angle and fracture mode between the groups. There was no difference in the bonding strength between the immersion dyeing group and the control group. The bonding strength of the immersion dyeing-masking group was significantly lower than those of other two groups. Subgroups coated with a silane coupling agent had significantly higher bonding strength than those without coating. Conclusion: The immersion dyeing has no significant effect on the bonding strength between zirconia ceramics and resins. The masking treatment after immersion dyeing can reduce the bonding strength between zirconia ceramics and resins. Coating silane coupling agents can significantly enhance the zirconia ceramics and resins bonding strength. References | Related Articles | Metrics

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Study on Vertical Changes in Untreated Skeletal Class Ⅲ Females with Various Vertical Growth Types SUN Ziye, GAO Hui, XIAO Danna 2020, 36(6): 599-602.  DOI: 10.13701/j.cnki.kqyxyj.2020.06.022 Abstract ( 203 )   PDF (781KB) ( 201 )   Objective: To investigate the vertical changes of jaws of skeletal class Ⅲ females with various vertical growth types in different growth stages by CBCT. Methods: A total of 270 females with skeletal class Ⅲ malocclusion with various vertical growth types were randomly selected from CBCT data and divided into pre-growth spurts, peak period, and post-growth spurts. Invivo 5.3 software was used to measure the correlation index. The results were analyzed and discussed. Results: In the high-angle group, the changes were statistically different in addition to the pre and the post peak comparison and the occlusal angle in each period. In the mean-angle group, the changes were statistically different in addition to the pre and the post peak comparison of PP-FH angle and the occlusal angle in each period. In the low-angle group, the changes were statistically different in addition to the pre and the post peak comparison of PP-FH angle and the occlusal angle in each period. Conclusion: In the process of growth and development, the vertical changes of the jaw in class Ⅲ malocclusion females with various facial skeletal types demonstrated significant differences References | Related Articles | Metrics

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Study on Root Resorption of Mandibular Second Molars with Long Distance Mesialization PAN Enjiu, DU Qingling, ZHU Jiejing, ZOU Mingyuan, GONG Guoliang, LIN Xinping 2020, 36(6): 603-606.  DOI: 10.13701/j.cnki.kqyxyj.2020.06.023 Abstract ( 247 )   PDF (1054KB) ( 237 )   Objective: To explore the root resorption of mandibular second molars after long distance (≥5mm) mesialization. Methods: A total of 45 mandibular second molars in 36 completed cases were retrospectively analyzed. The root length and axis inclination angle of the orthodontic molars were measured by direct digital panorama. According to the initial axial inclination of the molars, they were divided into group A (axial inclination <86.42°) and group B (axial inclination ≥86.42°). According to the change of axial inclination, they were divided into group C (change <10°) and group D (change ≥10°). The root resorption was calculated and the effect of axis inclination on root resorption was analyzed. Results: The root length was shortened (P<0.01). The mesial and distal root resorption values were approximately (P>0.05). The average root resorption was (0.97±0.40) mm. There was no significant difference between group A and group B in root resorption (P>0.05). Group C and group D had statistical significance only in the amount of distal root resorption (P<0.05). Conclusion: The root resorption of mandibular second molars after long distance mesialization is small and generally has no clinical significance. The change of axial inclination of the molars has a certain effect on the root resorption of the distal root. Orthodontic treatment should be started as soon as possible after the molar loss. References | Related Articles | Metrics