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Twenty-five Years of Evidence-based Dentistry: From Concepts to Practice HUA Fang 2018, 34(11): 1149-1153.  DOI: 10.13701/j.cnki.kqyxyj.2018.11.001 Abstract ( 404 )   PDF (935KB) ( 348 )   Since the establishment of Cochrane Oral Health Group in 1994, evidence-based dentistry (EBD) has been developed for 25 years. EBD-related concepts and methods have gradually gained recognition from dental experts and healthcare providers, and have become an integral component of dental care, education, research and policy-making. In order to help Chinese colleagues to achieve a better understanding of the essence and value of EBD, and to facilitate the further development of evidence-based dental research and practice in China, this article will briefly introduce the progress of EBD during the past 25 years and discuss its future prospect. References | Related Articles | Metrics

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Research Progress of Chondrogenic Progenitor Cells TAN Pei-jie, ZHU Song-song 2018, 34(11): 1154-1157.  DOI: 10.13701/j.cnki.kqyxyj.2018.11.002 Abstract ( 304 )   PDF (832KB) ( 358 )   Cartilage tissue has long been considered to be lack of self-healing capacity, and chondrocyte is considered to be the only cells in cartilage tissue. It is often easy to leave long-term pain and dysfunction after cartilage injury. However, with existing treatments, there are still difficulties to achieve a satisfactory outcome, which seriously affects patients' life quality. In recent years, with the development of biotechnology, tissue engineering, molecular biology technology, and stem cell therapy, the basic research in cartilage tissue made the breakthrough that provides new plans for treatments of cartilage injury. This thesis reviews the progress of research in cartilage stem cells. Currently, there is controversy about the nomenclature of stem cells derived from cartilage tissue. Therefore, chondrogenic progenitor cells (CPCs) is used in this thesis to describe cartilage stem cells. References | Related Articles | Metrics

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Research Progress on Canine Impaction WANG Han, GE Zhen-lin 2018, 34(11): 1158-1160.  DOI: 10.13701/j.cnki.kqyxyj.2018.11.003 Abstract ( 350 )   PDF (805KB) ( 597 )   Permanent canine impaction is considered as a common dental anomaly. The etiology remains poorly understood and the choices of treatment are various. This article reviewed the literature on canine impaction and the etiology, diagnosis, and treatment of impacted canine were discussed, hoping to provide reference for early clinical diagnosis and treatment. The etiology of canine impaction is related to hard tissue obstructions, local pathology, developmental disturbance, and genetic factors. CBCT and panoramic radiographs are essential for diagnosis. Orthodontic traction is the main treatment. Early detection of canine impaction gives the opportunity to stabilize stomatognathic system and contribute to the health of adjacent teeth. References | Related Articles | Metrics

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Etiological Factors of Losing Keratinized Gingiva Miyashaer·Hujiahemaiti, ZHOU Yan-min 2018, 34(11): 1161-1163.  DOI: 10.13701/j.cnki.kqyxyj.2018.11.004 Abstract ( 379 )   PDF (805KB) ( 775 )   Certain minimum width of keratinized gingiva is essential for ensuring both long term success rate and esthetic outcome of oral implants. Human keratinized gingiva is highly specialized stratified epithelia that forms borders between oral cavity and connective tissue to protect the body from physical and chemical damage, infection, dehydration and heat loss. However, it remains obscure that how periodontitis or any other risk factors affect re-epithelialization of human gingiva. In this review, we will discuss the cellular and molecular mechanism of gingival epithelial cells proliferation and differentiation. Meanwhile, we also try to explain certain etiological factors of losing keratinized gingiva. References | Related Articles | Metrics

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Research Progress in Pathogenesis of Oral Squamous Cell Carcinoma WANG Qian, HOU Da-wei 2018, 34(11): 1164-1167.  DOI: 10.13701/j.cnki.kqyxyj.2018.11.005 Abstract ( 925 )   PDF (819KB) ( 1934 )   The formation of oral squamous cell carcinoma is the accumulation of multiple gene mutations. Lymph node metastasis is one of the most important biological behaviors of OSCC, and it also has the greatest influence on the prognosis. The molecular biological mechanism of OSCC is still unclear. Exploring the molecular biological mechanism of OSCC is of great significance to clarify the pathogenesis of OSCC and to find potential therapeutic targets. This article reviews the pathogenesis of OSCC from the molecular biology perspective. References | Related Articles | Metrics

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Analysis of Salivary Markers in Oral Lichen Planus DONG Zi-yu, ZHANG Fang 2018, 34(11): 1168-1171.  DOI: 10.13701/j.cnki.kqyxyj.2018.11.006 Abstract ( 251 )   PDF (821KB) ( 222 )   Oral lichen planus (OLP) is a kind of chronic inflammation in oral mucosa with unknown etiology, which always relapses and has the risk of cancer. Many researchers have found that certain inflammatory factors of saliva and cancer related factors and microorganism can be used as markers to study the pathogenesis, condition evaluation, and prediction risk of cancer of OLP. This paper reviews the role of saliva markers in oral lichen planus. References | Related Articles | Metrics

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Distribution of Lactobacillus of the Uygur and Han Children in Bo Zhou, Xinjiang and Its Correlation with Caries DONG Ying, CAO Hong-fei, YANG Ting, LI Bei-bei, ZHAO Jin 2018, 34(11): 1172-1176.  DOI: 10.13701/j.cnki.kqyxyj.2018.11.007 Abstract ( 235 )   PDF (1249KB) ( 222 )   Objective: To investigate the distribution of oral lactobacillus and its relationship with caries among 3-5 years old children of Uygur and Han nationalities in Bo Zhou area. Methods: Totally 722 healthy children aged 3 to 5 years were selected with a stratified cluster random sampling method. Dental plaque samples were collected, and lactobacillus was cultured selectively through Rogosa and MRS agar medium. The isolates were further identified by methods of gram staining, hydrogen peroxide test, and polymerase chain reaction molecular biology methods. Pearson χ2 test was used for statistical analysis of classification data. Results: The prevalence of lactobacillus were 69.5% in Han children and 58.2% in Uygur children, respectively (P=0.001). The tested rate of lactobacillus in severe early childhood caries children group (75.4%) was significantly higher than that of early childhood caries children group (66.8%) and caries-free group (40.4%) (P=0.000). Lactobacillus could be isolated from 62.6% boys and girls of Uygur children and 63.8% of Han children (P=0.794) in the overall samples. The prevalence of lactobacillus was 57.5% in 3 years old children, 65.2% in 4 years old children, and 65.9% in 5 years old children, respectively (P=0.119). Conclusion: There was difference in the distribution of oral lactobacillus between Uygur and Han ethnic groups. There were significant differences in prevalence of lactobacillus between groups of severe early childhood caries, early childhood caries, and caries-free children. Lactobacillus may be a risk factor in the development of caries. References | Related Articles | Metrics

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Prevalence and Characteristics of Fused Roots at Maxillary Second Molars in Northern Chinese Population by Cone-beam Computed Tomography LU Guan-fan, MIN Yi, HAN Qi, LI Yu-hong 2018, 34(11): 1177-1181.  DOI: 10.13701/j.cnki.kqyxyj.2018.11.008 Abstract ( 275 )   PDF (1505KB) ( 157 )   Objective: To investigate the patterns and distributions of roots and root canals of fused roots at maxillary second molars (MSMs) in a northern Chinese population using cone-beam computed tomography (CBCT). Methods: The patients requiring CBCT inspections for diagnosis or treatment at Stomatology Hospital of Qingdao were selected. The gender and age of patients with fused root at MSMs were recorded and the configurations of root and canal of fused root at MSMs were probed. The collected data were analyzed to discover the root fusion variety in respect of genders, ages, and the patterns of fused root canal. Results: Totally 324 patients were involved in this study. The fused roots at MSMs appeared in 139 patients. The number of fused teeth was 222. The prevalence of each section of ages was different (P<0.05), mostly in the age section of 35 to 50 (70.9%). However, there was no significant difference between male and female, or right and left side. Following the 108 root canal mingling of 222 fused roots at MSMs, it was found the different patterns of root fusion inclined to different types of root canal mingling. Conclusion: MSMs commonly have a high prevalence of root fusion and canal mingling in a northern Chinese population. Understanding the various root and root canal patterns of fused root at MSMs is beneficial to the clinical practice. References | Related Articles | Metrics

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Clearup Effects of Nickel-titanium Rotary Instrument and Ultrasonic Irrigation on Endotoxin Level in Root Canals of Chronic Apical Periodontitis HU Yong-qing, LI Ya, LI Shu-juan, LIANG Xiang-yang, YANG Dong-ru 2018, 34(11): 1182-1185.  DOI: 10.13701/j.cnki.kqyxyj.2018.11.009 Abstract ( 234 )   PDF (805KB) ( 237 )   Objective: To study the clearup effects of nickel-titanium rotary instrument and ultrasonic irrigation on the endotoxin level in root canals of chronic apical periodontitis. Methods: Thirty maxillary anterior teeth clinically diagnosed with chronic apical periodontitis were randomized into three groups. Group A was prepared with nickel-titanium rotary instrument. Group B was given one minute ultrasonic irrigation with sterile distilled water after root canal preparation with nickel-titanium rotary instrument. Group C was given one minute ultrasonic irrigation with 3% NaClO after root canal preparation with nickel-titanium rotary instrument. The concentration of endotoxin in the root canals was detected before and after treatments. Results: There were no statistical differences between three groups before treatments (P>0.05). The endotoxin concentrations in the three groups were (8.52±2.04) EU/mL, (1.61±0.41) EU/mL, and (0.22±0.11) EU/mL, respectively after treatments (P<0.05). Conclusion: Nickel-titanium rotary instrument and ultrasonic irrigation has a good effect on the clearup effect of endotoxin level in the root canals, and the effect with ultrasonic irrigation for one minute with 3% NaClO was better than ultrasonic irrigation for one minute with sterile distilled water. References | Related Articles | Metrics

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Primary Vertical Root Fracture: 5 Cases Report and Review of Literature LI Hui-xu, LIU Gui-rong, ZHANG Yan, CHEN Yan-qing, XU Hai-ping, PAN Ke-qing 2018, 34(11): 1186-1191.  DOI: 10.13701/j.cnki.kqyxyj.2018.11.010 Abstract ( 241 )   PDF (3063KB) ( 372 )   Objective: To investigate the etiology and diagnosis of primary vertical root fracture. Methods: Five cases diagnosed as primary vertical root fracture were reported and the relevant literatures of etiology and diagnosis were reviewed. Result: Root hypoplasia, anatomical factors, occlusal trauma, and periodontitis were the main factors leading to primary vertical root fracture. The application of root apex locator, X-ray, CBCT, and the periodontal exploration could improve the accuracy of diagnosis. Conclusion: There are some predisposed factors in the occurrence of primary vertical root fracture, and the clinical manifestations are complex and diverse. Clinicians should improve the understanding of primary vertical root fracture to make early diagnosis and treatment. References | Related Articles | Metrics

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Correlation between Periodontitis and Hyperlipidemia HOU Da-wei, GUO Jian-qing, YUE Hai-quan, GOU Xue-li, LIU Rui-min 2018, 34(11): 1192-1195.  DOI: 10.13701/j.cnki.kqyxyj.2018.11.011 Abstract ( 285 )   PDF (887KB) ( 298 )   Objective: To explore the relationship between periodontitis and hyperlipidemia. Method: The serum from severe chronic periodontitis patients and healthy volunteers was gathered and tested the concentrations of cholesterol, triglycerides, high density lipoprotein, and low density lipoprotein. The influence of periodontal basic treatment for the blood lipid levels was researched. In addition, the rat experimental hyperlipoidemia and periodontitis models were established by high fat diet and periodontal ligation, whose blood lipid levels and expression of CD3, CD4, and CD8 in the periodontal tissue cells were detected by flow cytometry. Result: The blood lipid levels of severe chronic periodontitis patients were similar to that of health volunteers. The levels of cholesterol, triglycerides, high density lipoprotein, and low density lipoprotein of patients with severe periodontitis and hyperlipidemia were not significantly changed after periodontal basic treatment for 3 months. The results of this clinical test were further validated by animal experiments. The expression proportion of CD3+, CD4+, and CD8+T cells in the simple hyperlipidemia group were higher than that of blank control group. Conclusion: Periodontitis does not cause hyperlipidemia, but hyperlipidemia can promote periodontitis. References | Related Articles | Metrics

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Control Effect of Preimplantation Periodontitis in Elderly Patients with Moderate to Severe Periodontitis and Type 2 Diabetes Mellitus SU Zhe-jun, WANG Peng, HUO Feng, LI Yi-ping, CHEN Xue, MA Li 2018, 34(11): 1196-1199.  DOI: 10.13701/j.cnki.kqyxyj.2018.11.012 Abstract ( 288 )   PDF (808KB) ( 301 )   Objective: To investigate the effect of periodontal initial therapy on periodontal infection control, the changes in the level of MMP -8 in whole saliva and its clinical significance in elderly patients with moderate to advanced periodontitis with type2diabetes. Methods: 22 cases of elderly patients with moderate to severe periodontitis with type 2 diabetes were included in the experimental group, and 18 of the elderly patients with moderate and severe periodontitis were treated as the control group, and the whole periodontitis was treated with periodontal initial therapy. The clinical periodontal index and MMP-8 content in the whole saliva of two groups were detected before and 3 months after the periodontal initial therapy. Results: There was no significant difference in the levels of PD, PD>5 mm, BOP, and MMP-8 between two groups before therapy (P>0.05). The PD, PD>5 mm, BOP, and MMP-8 levels of two groups were significantly lower than those of baseline at 3 months after therapy, and the difference was statistically significant (P<0.05). There was no significant difference in the PD, PD>5 mm, and BOP between two groups (P>0.05), and the level of MMP-8 in the experimental group was not significantly lower than that in the control group (P<0.05). After 3 months of periodontal initial therapy, the PLI was less than 20%, the complete BOP was 22.7%, and the PD>5 mm was 13.6% in the experimental group. Conclusion: Simple periodontal initial therapy can improve the periodontal clinical indexes of elderly patients with moderate to advanced periodontitis with type 2 diabetes, and reduce the level of MMP-8 in the whole saliva. Periodontal infection control is satisfactory. Compared with elderly patients with moderate to advanced periodontitis, the effect of inflammatory therapy is poor after periodontal initial therapy in elderly patients with mo- derate to advanced periodontitis and type 2 diabetes. References | Related Articles | Metrics

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Effects of Orthodontic Accompanied with Periodontal Treatment on Gums in the Molar Area of Adult Periodontal Patients YANG Bao-kuan, SHI Xing-hui 2018, 34(11): 1200-1203.  DOI: 10.13701/j.cnki.kqyxyj.2018.11.013 Abstract ( 196 )   PDF (836KB) ( 207 )   Objective: To explore the clinical effects of orthodontic-periodontal treatment on gums in the molar area of adult periodontal patients, through the observation and analysis of periodontal status and gingival appearance index of molar. Methods: 24 patients with moderate or severe periodontal disease from our Department were included and treated with adequate periodontal support therapy. After periodontal inflammation was controlled, orthodontic treatment was performed by an experienced oral doctor. The plaque index (PLI), bleed on probing (BOP), modified bleeding index (BI), papilla presence index (PPI), probing depth (PD), and clinical attachment loss were compared before and after treatment. Results: 24 patients with moderate and severe periodontitis had significant improvement in oral plaque index (PLI), probe hemorrhage (BOP), bleeding index (BI), molar profile index (PPI) of the gum area and probing depth of periodontal pocket (PD) (P<0.05). The health condition of gums was significantly improved after treatment. Conclusion: After orthodontic combined with periodontal treatment, the deformity of the tooth was corrected, the occlusal relationship was rebuilt, and the gingival state of the molar area was improved, which is beneficial to the control of plaque and oral hygiene. So orthodontic accompanied with periodontal treatment is worthy of clinical application as a treatment option for patients with moderate to severe periodontal disease. References | Related Articles | Metrics

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Relationship between Expression of CD29 and Pathogenesis of Human Salivary Gland Benign and Malignant Tumors LIU Xin-can,ZHANG De-bao,LIU Zai-long 2018, 34(11): 1204-1207.  DOI: 10.13701/j.cnki.kqyxyj.2018.11.014 Abstract ( 221 )   PDF (2107KB) ( 192 )   Objective: To analyze and clarify the expression and distribution of various cell surface markers, especially the expression and distribution of CD29 in adult salivary glands. Methods: Paired adult parotid, sublingual and submandibular glands were collected. The phenotypic expression (including CD29) of various family-specific cell surface markers in the collected glands was examined using immunohistochemistry. Results: CD29 was expressed in the salivary gland acinar and duct epithelium, mesenchymal stroma, and myoepithelial cells. CD29+ cells were co-expressed in adult salivary gland epithelium with CD324, CD326, NKCC1, and CD44. Mesenchymal cells mainly expressed CD73, CD90, vimentin, and CD34. And α-SMA was the predominantly myoepithelial cell-specific progenitor markers. Conclusion: CD29 is widely expressed in human salivary glands and can be used as a potential biomarker for the treatment and diagnosis of salivary gland diseases and malignant tumors. References | Related Articles | Metrics

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Effects of DVDMS-PDT on Proliferation and Migration of Human Tongue Squamous Carcinoma Cell Line HSC-4 HUANG Yu-si, ZHANG Lei, LIU Le-tian, MA Yao, LIU Xin 2018, 34(11): 1208-1211.  DOI: 10.13701/j.cnki.kqyxyj.2018.11.015 Abstract ( 286 )   PDF (1505KB) ( 278 )   Objective: To study the proliferation and migration of oral tongue squamous cell carcinoma HSC-4 cells induced by DVDMS-PDT. Methods: To detect the cytotoxicity of DVDMS and the uptake of drugs by cells, the cells were divided into control group and DVDMS-PDT treatment group with different concentrations (0.1, 0.5, 1.0, 2.0, 3.0, 4.0, 5.0, 6.0, and 8.0 mg/L, respectively). The laser energy density were 0.75, 1.50, 3.00, 6.00J/cm2. The effects of different drug concentrations and light energy density on cell viability were analyzed by CCK-8. Scratch assay and Transwell experiment were used to observe the changes of cell migration ability. Results: DVDMS toxicity experiments showed that the single drug had less cytotoxicity, and combined with laser irradiation, it could significantly inhibit the proliferation of HSC-4 cells (P<0.05). Compared with the control group, the healing rate of scratch assay was decreased,and the number of transwell penetrated cells was decreased (P<0.05). DVDMS concentration at 2.0 mg/L, 6 hours incubation, and light energy density above 3.00J/cm2 could effectively kill HSC-4 cells. Conclusion: DVDMS-PDT can effectively kill the tongue squamous cell carcinoma cell line and inhibit the migration of HSC-4 cells. Photosensitizer concentration, incubation time, and light energy density are important factors affecting the therapeutic effect. References | Related Articles | Metrics

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Expression of STAT6 in Salivary Gland Adenoid Cystic Carcinoma and Its Effect on Cell Proliferation and Invasion PEI Hao, XIA Dong-jing, HUANG Ying-ying 2018, 34(11): 1212-1216.  DOI: 10.13701/j.cnki.kqyxyj.2018.11.016 Abstract ( 244 )   PDF (1914KB) ( 195 )   Objective: To investigate the expression of STAT6 in salivary gland adenoid cystic carcinoma (SACC), and the effects of down-regulation of STAT6 gene expression on cell proliferation and invasion. Methods: A total of 53 cases of SACC were selected. And 40 cases of normal gland tissues from benign parotid gland tumors were taken as the control group. Immunohistochemical method was used to detect the expressions of STAT6 proteins in SACC and adjacent tissues. The ACC-2 cells were cultured and divided into STAT6 interference sequence group, negative control group, and blank group. Small interfering RNA (siRNA) technology was used to down-regulate expression of STAT6 gene of cells in STAT6 interference sequence group. Real-time fluorescence quantitative PCR was used to detect the expression of STAT6 gene in cells. MTT colorimetric assay was used to detect cell proliferation. Transwell assay was used to detect cell migration and invasion. Results: The positive expression rate of STAT6 protein in SACC was 71.70%, which was higher than that of control group (P=0.000). The positive expression of STAT6 protein in SACC was related to TNM stage, lymph node metastasis, and distant metastasis (P<0.05). The relative expression level of STAT6 mRNA in cells in STAT6 interference sequence group was lower than that in negative control group and blank group (P<0.05). The absorbance values at 24-96h of cells in STAT6 interference sequence group was lower than those in negative control group and blank group (P<0.05). The number of migration cells and the number of invasive cells in STAT6 interference sequence group were lower than those in negative control group and blank group (P<0.05). Conclusion: The expression of STAT6 protein in the SACC tissues was high. Down-regulation of STAT6 gene expression could inhibit the cell proliferation, migration, and invasion. References | Related Articles | Metrics

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Effects of Adrb2 Agonists and Antagonists on Alterations of Alveolar Bone Remodeling and Expression of RANKL in Rat Tooth during Tooth Movement TANG Xiao-ying, LONG Yang,YUAN Xiao-ping 2018, 34(11): 1217-1222.  DOI: 10.13701/j.cnki.kqyxyj.2018.11.017 Abstract ( 283 )   PDF (3069KB) ( 145 )   Objective: To evaluate the effect of agonist and inhibitor of Adrb2 on the alveolar bone micro-structure reconstruction and osteoclast proliferation during the movement of orthodontic teeth in rats. Methods: 64 female SD rats were randomly divided into four groups: isoproterenol group, propranolol group, negative control group, and saline group. The rat orthodontic teeth movement models were established. The rats were injected corresponding reagents according to weight and were sacrificed on day 0, 7, 14, and 21. The movement distance of first molar of rats was measured by Vernier caliper. The numbers of osteoclasts were observed through TRAP staining. The change of micro-structure of alveolar bone was evaluated by Micro-CT. Results: The trends of the distance of teeth movement and numbers of osteoclast were the same: isoproterenol group> saline group> propranolol group> negative control group (P<0.05). Absorption lacuna increasing at the pressure side of alveolars could be observed through HE staining in isoproterenol group, saline group, and propranolol group and the isoproterenol group was the most. The result of Micro-CT scan showed that isoproterenol could reduce BV/TV and MTPD, and increase Tb.sp, while propranolol was on the opposite. Conclusion: Isoproterenol could promote the resorption of alveolar bone at the pressure side and increase the osteoclast numbers so that the alveolar bone became looser which was beneficial to the movement of orthodontic tooth. On the contrary, propranolol could inhibit the proliferation of osteoclast, increase the density of alveolar, and slow down the movement of tooth. References | Related Articles | Metrics

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Long-term Effects of Three Orthodontic Appliances on Periodontal Inflammation and Inflammatory Factors in Gingival Crevicular Fluid ZUO Zhi-gang, LI Hong-fa, XU Jin, ZHENG Zhao, WU Jie, LIU Da-yong 2018, 34(11): 1223-1227.  DOI: 10.13701/j.cnki.kqyxyj.2018.11.018 Abstract ( 286 )   PDF (827KB) ( 340 )   Objective: To compare the long-term effects of orthodontic brackets without brackets, self-ligating brackets, and traditional metal bracket appliances on patients' oral hygiene. Methods: 30 patients with orthodontics treatment in our hospital from March 2015 to December 2015 were selected. The average age was 21.20±2.15 years old. After the patient completely cleaned up plaque and calculus, Invisalign, DAMON Q, and the traditional metal bracket appliance (Victory Series) were used. After 1, 3, 6, 12, 18, and 24 months, the patients' gingival index, sulcus bleeding index, calculus index, debris index, and gingival crevicular fluid IL-1β and TNF-α were measured. Results: There was no significant difference in gender, age, Angle class distinction, and periodontal index between the groups (P>0.05). After 3 months of treatment, the periodontal index of each group increased compared with baseline (P<0.05). No significant difference was found except for the debris index (P>0.05). From 6 to 12 months, The periodontal index of the lock bracket and the traditional bracket group was significantly higher than that of the invisible group (P<0.05). After 18 months, there was no significant difference in the gin－ gival index and sulcus bleeding index between three groups (P>0.05). The expression of IL-1β and TNF-α in the three groups from January to September was significantly increased (P<0.05). After 9 months, the expression of the invisible group tended to be stable, and the difference was not statistically significant (P>0.05). The expressions of the trough group and the traditional bracket group were higher from September to December and then decreased gradually. There was no significant difference between the trough and the invisible group after 24 months (P>0.05). Conclusion: This study observed the long-term effects of three appliances on oral hygiene, confirming that the invisible appliance with or without brackets contributes to oral hygienic preservation during the initial correction period. However, after 18 months of orthodontic treatment, the effect is not obvious. References | Related Articles | Metrics

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Relevance of Malocclusion Type and Body Dysmorphic Disorder in Young University Students WU Ting-yun,YANG Dong,WANG De-tang,WU Ai-min,RUAN Qiong,HE Shang-qun,LI Yang 2018, 34(11): 1228-1231.  DOI: 10.13701/j.cnki.kqyxyj.2018.11.019 Abstract ( 278 )   PDF (867KB) ( 278 )   Objective: To explore the correlation between malocclusion types and the incidence of body dysmorphic disorder in young university students, and to guide university students to actively face the formation of malocclusion and provide a clinical treatment basis for students with both body dysmorphic disorder and malocclusion. Methods: A total of 1628 students in Jingchu University of Technology were randomly selected to screen students with malocclusion. Angle's classification of malocclusion was used to determine the number of three types of malocclusion. The Scale of Satisfaction with the Body Image (SSBI) was used to investigate, analyze, and rate the relationship between different types of malocclusion and body dysmorphic disorder. Results: The incidences of Classes I, II, and III malocclusion in young university students were 64.41%, 19.52%, and 16.07%, respectively. The detection rates of students with body dysmorphic disorder in those with Classes I, II, and III malocclusion were 11.13%, 19.73%, and 28.93%, respectively. In the 8 dimensions of the SSBI, the scores of students with Classes I, II, and III malocclusion in each dimension went higher successively. Among these dimensions, the differences in scores of emotional impairment, social interaction and changes in physical appearance were statistically significant (P<0.05). Conclusion: The incidence of body dysmorphic disorder in young university students with Classes I, II, and III malocclusion went higher successively. Emotional impairment, social interaction, and changes in physical appearance were the most urgent problems for university students with body dysmorphic disorder, and psychological assessment in students with Class III malocclusion should be particularly emphasized. This study provides a theoretical basis for the psychological intervention of young university students in clinical orthodontic treatment. References | Related Articles | Metrics

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Preparation and Mechanical Properties of New Dental Composite Resin LI Di, LI Bao-quan, WEI Yu-xue, NIU Ju, ZHAO Wen-di, LIU Dan-dan, NA Hui, LIU Xiao-qiu 2018, 34(11): 1232-1234.  DOI: 10.13701/j.cnki.kqyxyj.2018.11.020 Abstract ( 249 )   PDF (1191KB) ( 261 )   Objective: To evaluate the effect of nanometer/micron SiO2 mixed filler on mechanical properties of a new type of dental composite resin. Methods: A new type of dental composite resin was prepared by adding nanometer/micron SiO2 mixed packing to monomer of TMBPEA. The experiment was divided into five experimental groups and one control group with Bis-GMA as the monomer, and the flexural strength and elastic modulus of each group were tested. The section morphology of samples containing SiO2 fillers were observed by SEM. Results: The mechanical properties of the samples with TMBPEA and 50% SiO2 filler were the highest. Its bending strength and elastic modulus were (96.83+0.55) MPa and (7.12±0.20) GPa, respectively. SEM results showed that the inorganic filler of the sample was dispersed uniformly in the continuous organic matrix. Conclusion: The composite resin with TMBPEA as matrix has promising application prospect. References | Related Articles | Metrics

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Effect of Two Desensitizers on Bond Strength of Different Cements to Dentine GU Meng-qin, TAN Yu-jie, LI Wang-yang, GUO Ling 2018, 34(11): 1235-1239.  DOI: 10.13701/j.cnki.kqyxyj.2018.11.021 Abstract ( 231 )   PDF (1409KB) ( 227 )   Objective: To evaluate the effect of two desensitizers on shear bond strength (SBS) of dentine to resin composite of three cements after thermal-cycling. Methods: 96 premolars were divided into three groups: Duraphat, Prime&Bond NT, and control groups. Two premolars from each group were selected for scanning electron microscopy (SEM), and the remnant were assigned to three subgroups (n=10): RelyX U200, glass ionomer cement (GIC), and resin modified glass ionomer cement (RMGIC/RelyX Luting2 Cement). After 24 h storage in 37℃ water bath and thermal-cycling (5℃/ 55℃), the SBS of all groups was tested by universal testing machine. Results: Two desensitizers occluded the dentine tubules at varying degrees. Duraphat reduced the SBS significantly (P<0.05); the Prime&Bond NT + RelyX U200 improved the retentive strength (P<0.05), however, the Prime&Bond NT + GIC reduced the SBS (P<0.05), and there was no significant difference in the Prime&Bond NT + RMGIC group (P>0.05). After thermal-cycling for 24 h, the SBS values of all groups were reduced (P<0.05), and the maximum value was Prime&Bond NT + RelyX U200 group. Conclusion: Two desensitizers have different effects on three cements, and the Prime&Bond NT can enhance the SBS of RelyX U200. References | Related Articles | Metrics

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Comparative Study on Polishing Effect of Zirconia by Different Polishing Tools ZHANG Xiao,JI Yang,LIU Bao-ying,DENG Qing-wan,ZHANG Shan,CHEN Wen-bo 2018, 34(11): 1240-1243.  DOI: 10.13701/j.cnki.kqyxyj.2018.11.022 Abstract ( 238 )   PDF (1460KB) ( 473 )   Objective: To compare the effect of different polishing tools on the surface properties of zirconia after polishing. Methods: 40 zirconia blocks specimens (13 mm×10 mm×3 mm) were randomly divided into 5 groups (n=8): Group A (blank control group), group B (negative control group), group C (SHOFU), group D (KOMET), and group E (EVE). The effect of polishing was measured by the Ra value, the vickers hardness, and the surface morphology. Results: The Ra values of zirconia specimens were not exactly the same, and the differences were statistically significant(F=273.200,P=0.000). The mean Ra values of each group were as follows: E<A, B, D<C, and the differences were statistically significant. The results of SEM were consistent with the surface roughness. The hardness values of zirconia specimens were the same after surface treatment, and the difference was not statistically significant (F=2.603,P=0.053). Conclusion: The effects of different polishing tools on zirconia were significant. EVE zirconia polishing tool achieved the best performance, which was comparable to the surface properties of zirconia after sintering. The effect of SHOFU zirconia polishing tool was poor, which was worse than that of white sand and sintering. References | Related Articles | Metrics

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TLR4-MyD88 Signal Pathway in Trigeminal Ganglia Involved in Immunoreactivity Induced by Temporomandibular Joint Inflammation in Rats LI Wei-jia,LI Lu-jia, FAN Fan, JIN Hai-wei 2018, 34(11): 1244-1248.  DOI: 10.13701/j.cnki.kqyxyj.2018.11.023 Abstract ( 201 )   PDF (2760KB) ( 276 )   Objective: To investigate the dynamic expression of TLR4 and its signal pathway in trigeminal ganglia (TG) by using a temporomandibular joint inflammation (TMJI) animal model in rats, and further to explore the role of TLR4 signal pathway involved in the neural immune response during process of TMJI and accompanied pain. Methods: Rats model of TMJI were established by intra-articular injection of Freund's adjuvant complete. Histopathological examination showed the progressive pathological changes in the TMJ were detected by HE staining, and the expression of TLR4 or MyD88 in TG were observed by immunohistochemistry. Results: The expression of TLR4 and MyD88 in TG increased significantly post TMJI. Correlation analysis showed low correlation between TLR4 and MyD88 expression. Conclusion: TLR4-MyD88 signal pathway in TG involved in neural immune response during TMJI. The signal transduction of activation of TLR4 in neurons may be mediated by MyD88 dependent pathway. References | Related Articles | Metrics

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Comparison of Expression of Mesenchymal Stem Cell Surface Markers on Synovial Mesenchymal Cells of Patients with Temporomandibular Joint Disease LU Hong-yan, LI Jian, LONG Xing 2018, 34(11): 1249-1252.  DOI: 10.13701/j.cnki.kqyxyj.2018.11.024 Abstract ( 274 )   PDF (1260KB) ( 276 )   Objective: To detect whether mesenchymal stem cells (MSCs) markers (CD34, CD73, CD90, CD105, CD271) were expressed in synovial mesenchymal cells(SMCs) of temporomandibular joint and to compare their expression in SMCs of temporomandibular joint from human osteoarthritisis and condylar hypertrophy. Methods: SMCs of temporomandibular joint were isolated using explants culture method and MSCs were obtained by the repeated adherent culture method. Then, the third generation cells were characterized and the expression of CD73, CD90, CD105, CD271, and CD34 were qualified by flow cytometry. Results: Fluorescence-activated cell sorting (FACS) analysis showed more than 90% MSCs from human iliac bone and SMCs from human temporomandibular joint expressed CD73, CD90, and CD105, less than 1% cells expressed CD271, and the quantification of CD34 was 0.47%-30%. Conclusion: MSCs from human iliac bone and SMCs of temporomandibular joint from human were positive for CD73, CD90, and CD105, while the expression of CD34 and CD271 were low. SMCs of temporomandibular joint with osteoarthritisis contained more cells positive for CD34 antigens than those from temporomandibular joint condylar hypertrophy. References | Related Articles | Metrics

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Expression of SIRT1 in Synovium of Temporomandibular Joint Osteoarthritis LIU Li, FENG Ya-ping, ZHAO Su-li, LONG Xing , KE Jin 2018, 34(11): 1253-1256.  DOI: 10.13701/j.cnki.kqyxyj.2018.11.025 Abstract ( 247 )   PDF (1854KB) ( 174 )   Objective: To investigate the expression of SIRT1 in the synovial of temporomandibular joint osteoarthritis(TMJ OA). Methods: HE staining was used to observe the synovial tissue morphology. Immunohistochemistry was used to detect the expression and distribution of SIRT1 in synovial tissue. The human TMJ synovial cells were cultured in vitro by tissue explantation. Western blotting and real-time PCR were used to detect the SIRT1 protein and gene expression in synovial cells. Results: HE staining showed that the synovial membrane of the OA group was significantly thicker than the normal group, and the blood vessels increased. Immunohistochemistry showed that the staining intensity of SIRT1 in the OA group was significantly higher than that in the normal group (P<0.05). Real-time PCR and Western blotting showed that the expression of SIRT1 in synovial cells of OA group was significantly higher than that of normal group (P<0.05). Conclusion: The expression of SIRT1 in the synovium of TMJ OA is closely related to the occurrence and development of osteoarthritis, providing a new theoretical basis for the molecular mechanism and treatment of this disease. References | Related Articles | Metrics

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Analysis of Malpositioning in Digital Panoramic Radiographs of Patients with Different Dentitions FENG Jing, WANG Xiao-yun, CHEN Li, YAN Hong-jing, WANG Bo, SONG Zi-qi, LI Zhi-min 2018, 34(11): 1257-1260.  DOI: 10.13701/j.cnki.kqyxyj.2018.11.026 Abstract ( 249 )   PDF (1536KB) ( 251 )   Objective: To discuss the method of improving the quality of panoramic tomography. Methods: 498 digital radiographs taken from the hospital were selected, which were divided into permanent dentition group, mixed dentition group, and edentulous dentition group. The common errors made in the digital panoramic radiographs were analyzed. Results: In the mixed dentition group, the mean number of errors per radiograph was significantly higher than that in the permanent dentition radiographs and edentulous dentition radiographs. The errors of “the chin is tipped too high”, “patient's neck is stretched forward on a slant”, and “tongue is not on the plate” were significantly more prevalent in the edentulous dentition group. Children with mixed dentitions were prone to moving and positioning heads too backward during the radiograph procedure. Conclusion: Properly positioning the patients with different types of dentitions is the most important factor in preventing a cascade of errors and improving imaging quality. References | Related Articles | Metrics