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Comparison of Two Methods to Modify Groove Titanium Plate with Fibronectin. HUANG Si-Jia, XU Zhi-Qiang, LAI Ying-Zhen, ZHOU Lin, CHEN Jiang. 2016, 32(12): 1225-1228.  DOI: 10.13701/j.cnki.kqyxyj.2016.12.001 Abstract ( 262 )   PDF (1287KB) ( 258 )   Objective: To compare the effect of modification of titanium plate with fibronectin (Fn) using three fluoroethane sulfonyl chloride and silane. Methods: Three fluoroethane sulfonyl chloride and silane were used to bond Fn on the micro grooves titanium surface. XPS was applied to analyze and compare the surface elements of different materials. Fluorescence staining was used to observe the quantity and distribution of protein on different material surfaces. DAPI staining was used to detect the early attachment of cells after HGF was seeded on different material surfaces for 2h, 4h, and 6h. The cell proliferation rates were compared by CCK-8 assay after HGF was seeded on the surface for 6h, 12h, 1d, 3d, 5d, 7d. Results: XPS results indicated that the protein content of the surface of the silane group was higher than that of the three fluorine group and the blank group (P<0.05). The content of silane group suggested that fibronectin surface immunofluorescence was higher than that of three fluorine group and blank control group (P<0.05). DAPI staining indicated that the number of cells attached to the three groups was comparable. However, after 4h and 6h, the number of cells on the surface of silane group was significantly higher than that of other two groups (P<0.05). CCK-8 results indicated that the cell proliferation rate of silane group was higher than those of three fluorine group and blank group at six time periods (P<0.05). Conclusion: The effect of silane modified method is better than three fluoroethane sulfonyl chloride to bond fibrin on the titanium plate. References | Related Articles | Metrics

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Effects of Ursolic Acid on Proliferation and Mineralization of Cementoblasts WANG Yu-zhuo, BAO Xing-fu, JIANG Huan, GAO Shang, LIU Jin-feng, WANG Chun-hui, HU Min 2016, 32(12): 1229-1233.  DOI: 10.13701/j.cnki.kqyxyj.2016.12.002 Abstract ( 245 )   PDF (2214KB) ( 236 )   Objective: To investigate the effect of ursolic acid on murine cementoblasts cell line OCCM-30 in vitro. Methods: Cementoblasts were incubated with ursolic acid at various concentrations. Proliferation was detected using cck-8 assay. Cell cycle and apoptosis were checked by flow cytometry analysis. The activity of alkaline phosphatase was tested by enzyme-linked method on microplate. The mineralization was tested by alizarin red S staining. Results: Compared with the control group, ursolic acid (2.5μmol/L) increased the cell proliferation rate and proliferation index of the cell cycle, reduced the early apoptotic rate, up-regulated the activity of alkaline phosphatase and the quantity of the mineralized nodules. Conclusion: Ursolic acid can promote the proliferation of cementoblast, enhance the activity of alkaline phosphatase, and facilitate the differentiation. References | Related Articles | Metrics

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Pulp Response of Beagle Dog to Direct Capping with iRoot BP Plus. MEI Xue, XIE Li-ping, JIN You-hong, YE Fang, XIONG Wei, YUE Li, JIANG Shan. 2016, 32(12): 1234-1239.  DOI: 10.13701/j.cnki.kqyxyj.2016.12.003 Abstract ( 304 )   PDF (3020KB) ( 404 )   Objective: To observe calcific bridge formation, pulp inflammation and the color change of the teeth capped with iRoot BP plus in beagle dogs. Methods: Two 10-month old beagle dogs were selected. A total of 72 teeth in the two dogs were randomly assigned into iRoot BP plus group, MTA group and control group (glass ionomer group). Eight weeks and 12 weeks after direct pulp capping with iRoot BP plus, MTA or glass ionomer, the teeth were extracted. Then histological sections were made and stained with hematoxylin eosi. Calcified bridge formation and dental pulp inflammation were graded, and the change of tooth color was evaluated. Wilcoxon rank sum test was used for statistical analysis. Results: In the iRoot BP Plus or MTA group, most of the specimens formed a complete calcification bridge without pulp inflammation. While in the glass ionomer group, no obvious calcified bridge formation was observed, but the inflammatory reaction, reticular atrophy of the pulp and vacuolar degeneration of the odontoblastic layer appeared. Tooth discoloration was observed in MTA group but not in iRoot BP Plus group. Conclusion: 1) Both iRoot BP Plus and MTA can induce the formation of calcified bridge. 2) iRoot BP Plus and MTA have a good resistance to inflammation. 3) iRoot BP Plus is a better pulp capping agent than MTA. References | Related Articles | Metrics

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Effects of EMP1 on the Proliferation, Migration and Invasion of Oral Squamous Cancer Cells in Vitro. ZHANG Jun, DAI Xiao-hua, ZOU Hui-ru, LIAN Xiao-li, LI Yan-ni. 2016, 32(12): 1240-1243.  DOI: 10.13701/j.cnki.kqyxyj.2016.12.004 Abstract ( 216 )   PDF (2573KB) ( 258 )   Objective: To investigate the effects of EMP1 on the proliferation and invasion of oral squamous cancer cells(OSCC) in vitro. Methods: pEGFP-N1-EMP1expression vectors were constructed and transfected stably into Tb3.1 cell. Tb3.1-pEGFP-N1-EMP1 cell, wild type Tb3.1 cell and Tb3.1-pEGFP-N1 cell were tested using MTT to assay cell proliferation. Cell cycle and invasion were analyzed by flow cytometry and invasion assay, respectively. One-way ANOVA was adopted to compare among groups. Results: Compared with wild type Tb3.1 cell and Tb3.1-pEGFP-N1 cell, the growth of Tb3.1-pEGFP-N1-EMP1 cell was inhibited, and the proportion of cells in S and G2-M phase and the number of invasive cells were reduced in Tb3.1-pEGFP-N1-EMP1 cell (P＜0.05). Conclusion: EMP1 may negatively regulate the proliferation, migration and invasion of tumor cells in the oncogenesis and development of OSCC. References | Related Articles | Metrics

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Preparation ofNano-scale Freshwater Pearl Powder MAO Qiu-hua, XU Pu, WANG Bin-ping, LI Mu-yuan, CHENG Ya-nang, LIAO Jun , CHEN Lin, LU Li-ying, YU Dou, WANG Xiu-li. 2016, 32(12): 1244-1247.  DOI: 10.13701/j.cnki.kqyxyj.2016.12.005 Abstract ( 258 )   PDF (1632KB) ( 383 )   Objective: To prepare nano-scale pearl powder by mechanical ball milling method. Methods: The size of nano-scale freshwater pearl powder was analyzed by laser particle size analyzer (LPSA), scanning electron microscope (SEM) and transmission electron microscopy (TEM). The protein and amino acid content of freshwater pearl powder were analyzed and compared by Kjeldahl method referred to the determination of amino acids in foods (GB/T 5009.124-2003). Results: Micro-pearl powder can be ground into nano-scale by wet ball milling method using absolute ethanol as the medium, which did not change the protein and amino acid content significantly. Conclusion: Nano-scale pearl powder can be prepared by mechanical ball milling method by using absolute ethanol as the medium. References | Related Articles | Metrics

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Effect of Heat Treatment on the Forces of Buccal Multiloop Appliance during Mouth Opening and Closing Movement ZHANG Bo, WANG Pei-jun, XU Shi-qian, HOU Lu, WANG Li-qi. 2016, 32(12): 1248-1251.  DOI: 10.13701/j.cnki.kqyxyj.2016.12.006 Abstract ( 233 )   PDF (1324KB) ( 208 )   Objective: To evaluate the effect of heat treatment on the forces of buccal multiloop appliance during mouth opening and closing movement. Methods: Stretch-inflection-compression experiment was used to simulate the buccal multiloop appliance during mouth opening and closing movement. Different kinds of heat treatment were discussed in this article. Results: The forces and displacement distance of the buccal multiloop appliance during mouth opening and closing movement increased when it was bended after heat treatment, among which 480℃ was the most obvious. It showed no effect on the displacement distance when it was bended before heat treatment. Conclusion: When making buccal multiloop, the mechanical property of loop can be improved provided the heat temperature was 480℃ and the loop was bended afterwards. References | Related Articles | Metrics

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Three-dimensional Finite Element Analysis of Stress Distribution under Different Bone Conditions in All-on-4 Therapy GE Yi-Chen, JIANG Shao-Kang, LI Qing-Ru, ZHU Zhuo-Li. 2016, 32(12): 1252-1256.  DOI: 10.13701/j.cnki.kqyxyj.2016.12.007 Abstract ( 293 )   PDF (3450KB) ( 398 )   Objective: To study the influence of the varying inclination angles of distal implants and cantilever lengths of All-on-4 denture on stress distribution of implants and peri-implant bone tissues at different bone densities and to provide evidence for clinical applications. Methods: An edentulous mandible was scanned by CBCT. The DICOM digital images were obtained from CBCT and imported into Mimics for 3D-reconstruction. Geomagic studio was used to transfer the numerical model to entity. Unigraphics and ANSYS Workbench were deployed to found the three-dimensional finite element model simulating All-on-4 denture. When the lengths of prosthetic arcs were equal, models were modified in inclination of distal implants and cantilever lengths under Type Ⅱ and Type Ⅲ bone conditions. Static vertical forces of 150N were applied to the bilateral distal ends of each cantilever to analyze the stress distribution on implants and bone tissues nearby. Results: When angles of inclination were set 30°, 45°and 60°, the corresponding cantilever lengths were 10.8mm, 8mm and 6.3mm. The maximum stress values in Type Ⅱ bone condition were 26.8MPa, 23.5MPa and 16.3MPa and those in Type Ⅲ were 40MPa, 29MPa and 21.8MPa. Conclusion: The lower the bone density, the greater the stress values in peri-implant cortical bone. When the lengths of dental arcs were equal, an increase in angles of inclination with the successive decrease in cantilever lengths could effectively diminish the stresses in peri-implant bone tissues. References | Related Articles | Metrics

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Expression of LC3B in Local Tissues and T Cells of Oral Lichen Planus. ZHANG Na, ZHANG Jing, TAN Ya-qin, DU Ge-fei, LU Rui, ZHOU Gang 2016, 32(12): 1257-1260.  DOI: 10.13701/j.cnki.kqyxyj.2016.12.008 Abstract ( 235 )   PDF (2146KB) ( 191 )   Objective: To investigate the expression level of autophagy-related protein LC3B in local tissues and T cells of oral lichen planus (OLP). Methods: The expression of autophagy-related protein LC3B in OLP local tissues and T cells was investigated by immunohistochemistry and multi-color immunofluorescence staining, respectively. In addition, the associations between LC3B and the clinical features of OLP were analyzed. Results: The expression of LC3B in OLP local tissues and T cells was significantly increased compared with that in controls (P<0.001, P<0.01, respectively), and was negatively correlated with the RAE scores of OLP patients (P<0.05, P<0.01, respectively). Besides, the expression of LC3B in nonerosive OLP tissues was higher than that in erosive OLP tissues (P<0.01). Conclusion: LC3B may participate in the local immunopathogenesis of OLP. References | Related Articles | Metrics

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Surgical Management and Reconstruction of Facial Giant Basal Cell Carcinoma. PATIGULI Wusiman, ABDULHEKIM Yarbag, AINIWAER Mijiti, ADILI Moming. 2016, 32(12): 1261-1264.  DOI: 10.13701/j.cnki.kqyxyj.2016.12.009 Abstract ( 292 )   PDF (1772KB) ( 452 )   Objective: To explore the surgical management and reconstruction of facial giant basal cell carcinoma. Methods: Seventeen patients with giant basal cell carcinoma in the head and neck region undergoing surgical excision and reconstruction at our hospital were enrolled. Medical charts were retrospectively reviewed and analysed. Results: The lesion was usually in the forehead, eyelid, lips or nasal-cheek region. The diameter of the greatest ranged from 5 to 11 cm, and 5-6 cm was the most common size when diagnosed. All patients underwent synchronous tumor resection and reconstruction (mostly local advancement flap) with no postoperative flap failure. Conclusion: Giant basal cell carcinoma in the head and neck can be successfully treated with synchronous tumor resection and local advancement flap reconstruction. References | Related Articles | Metrics

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Comparison of Oral Microbial Diversity in Healthy People and Patients with Dental Caries and Periodontal Disease. SHI Yan, LI Chen-jie, ZHANG Ming-zheng, WANG Xin, YANG Shao-Guo, MENG Fan-Jin, CHEN Ting-Tao, YANG Jian. 2016, 32(12): 1265-1268.  DOI: 10.13701/j.cnki.kqyxyj.2016.12.010 Abstract ( 311 )   PDF (3883KB) ( 478 )   Objective: To compare the microbial diversity of healthy people and oral patients with high-throughput sequencing method and to provide basic data for curing dental caries and periodontal diseases. Methods: The patients with typical dental caries and periodontal diseases were selected. Their stimulated whole saliva and oropharyngeal samples were collected for high-throughput sequencing analysis and the microbial diversity among samples were analyzed using bioinformatics. Results: The Venn results indicated that a mean of 315 operational taxonomic units (OTUs) was obtained, and 73, 64,53, 19 and 18 common OTUs belonging to Firmicutes, Bacteroidetes, Proteobacteria, Actinobacteria and Fusobacteria were identified in healthy people. In addition, the relative richness results indicated that the Firmicute was reduced in children group and increased in youth group and adult group, while the Proteobacteria was increased in children group but reduced in youth group and adult group. Conclusion: The age bracket and oral disease had largely influenced the tooth development and microbial development in oral cavity, and the traditional "pathogenic bacteria" of Firmicutes, Proteobacteriaand Bacteroidetes might exert beneficial effects on oral health. References | Related Articles | Metrics

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Clinical Observation of GTR Combined with Bone Grafting in Endodontic Microsurgery. CHEN Yao, SHEN Jing. 2016, 32(12): 1269-1272.  DOI: 10.13701/j.cnki.kqyxyj.2016.12.011 Abstract ( 390 )   PDF (1306KB) ( 435 )   Objective: To evaluate the effects of endodontic microsurgery in large persistent periapical lesions combined with guided tissue regeneration (GTR) and anorganic bovine bone. Methods: A total of eighty patients with persistent apical periodontitis (≥10 mm in periapical radiographs) were included and randomly grouped into two groups. During the endodontic microsurgery, the defect in the test group was filled with anorganic bovine bone and covered by resorbable collagen membrane. In the control group, neither graft nor membrane was used. Six months and one year later, the clinical index was recorded. Results: The success rate of the experimental group was significantly higher than that of the control group after 6 months (P＜0.05), while the difference was not statistically significant after one year. There was no significant difference in the success rate after 6 months, when the lesion had a perforated palatal/lingual cortical plate. However, the difference was statistically significant after one year (P＜0.05). Conclusion: GTR combined with anorganic bovine bone can significantly promote the regeneration of the bone and reduce the healing time, which is beneficial to the healing of the large periapical lesion with a perforated palatal/lingual cortical plate. References | Related Articles | Metrics

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Characteristics of Masticatory Muscle Activity in Generalized Aggressive Periodontitis. REN Song, LI Bo, PAN Ya-ping. 2016, 32(12): 1273-1277.  DOI: 10.13701/j.cnki.kqyxyj.2016.12.012 Abstract ( 207 )   PDF (1609KB) ( 270 )   Objective: To analyze the masticatory muscle electromyographic activity in generalized aggressive periodontitis (GagP) patients. Methods: The electromaography of anterior temporalis (TA), masseter muscle (MM), digastric anterior (DA) and sternocleidomastiod (SCM) were recorded in differential mandibular positions. The electromaography (EMG) was analyzed using bundled software. Results:In the resting position, the electromyography values of anterior temporalis, masseter muscle, digastric anterior and sternocleidomastiod of periodontitis group were higher than those of the control group. In the intercuspal position, the electromyography values of anterior temporalis, masseter muscle of periodontitis group were lower than those of control group (P＜0.001). In the resting position, anterior temporalis, masseter muscle, digastric anterior and sternocleidomastiod of periodontitis group showed low electromyographic activities, TA＞MM＞DA. In the intercuspal position, TA＞MM;In the protrusive position, DA＞MM＞TA;In the retruded contact position, DA＞MM,TA＞MM. The differences were statistically significant (P＜0.05). In the intercuspal position, the asymmetry index of electromyography values of anterior cntemporalis, masseter muscle of periodontitis group were lower than those of the control group(P＜0.05). Conclusion: The masticatory function of the patients with GagP was impaired by the damaged periodontium. The patients with GagP showed unbalanced chewing activity, muscle dysfunction and masticatory muscle tension imbalance in left and right side. References | Related Articles | Metrics

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Comparison of CBCT and Periapical Radiograph in the Diagnosis of Chronic Periodontitis. YE Jing, ZHANG Zhi-hong 2016, 32(12): 1278-1281.  DOI: 10.13701/j.cnki.kqyxyj.2016.12.013 Abstract ( 231 )   PDF (986KB) ( 409 )   Objective: To assess the value of CBCT in the diagnosis of chronic periodontitis. Methods: Included in this study were twenty patients with chronic periodontitis who took bothfull mouth CBCT and the periapical radiograph of posterior teeth. They also received periodontal clinical examinations. The alveolar bone resorption at the medial-distal and lingual-buccal sites of 276 posterior teeth were measured by CBCT and periapical radiographs. Thecomparison between these two methods was done. Results: There was no significant difference in measuring the amount of resorption between CBCT and the clinical examination. However, the bone loss measured by periapical radiographs was less than those measured by CBCT and clinical examination.There was significant difference in the measured alveolar bone resorption among CBCT, clinical examination and periapical radiographs. Conclusion: CBCT is more accurate in the diagnosis of chronic periodontitis compared with periapical radiographs. References | Related Articles | Metrics

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Analysis of Radiographic Technical Quality of 2306 Root Canal Obturation Performed by Endodontists. ZHU Qi, GAN You-hua, ZHAO Li, ZHANG Shu-xin, ZHANG Jie 2016, 32(12): 1282-1286.  DOI: 10.13701/j.cnki.kqyxyj.2016.12.014 Abstract ( 249 )   PDF (818KB) ( 689 )   To evaluate radiographically the technical quality of root canal treatment performed by endodontists among an adult population attending the dental clinic in Dongguan, China between 2012 and 2013. Methods: A random sample of 1600 records of patients who received dental treatment at Jianli Stomatological Hospital of Dongguan between 2012 and 2013 was examined. A total of 1391 endodontically treated teeth with 2306 root canals in 1050 dental patients were evaluated. For each root-filled tooth, at least three periapical radiographs were examined: preoperative, working length determination and postoperative. The length, density and taper of root fillings were recorded. The length of root fillings was recorded as adequate, short or overfilled based on their relationship with the radiographic apex. Density and taper of fillings were recorded as adequate or inadequate based on the presence of voids and the uniform tapering of the fillings, respectively. Chi-square analysis was used to determine the adequacy of root canal filling in teeth with different location, position or curvature. Results: Eighty-seven percent, 69.8% and 75.8% of the root fillings had adequate length, density or taper, respectively. And only 57.8% of the root fillings fulfilled these criteria at the same time. The relationship between the length, density or taper of the root fillings and the canal curvature was statistically significant (P<0.001). Adequate fillings were found more in maxillary teeth than in mandibular teeth (P<0.001), in anterior teeth compared to posterior teeth (P<0.001), and in straight canals compared to curved canals (P<0.001). The highest percentage of adequate root fillings was found in maxillary incisors (78.8%). Conclusion: The acceptability of root fillings among an adult Chinese population performed by endodontists was found to be more than 50%. References | Related Articles | Metrics

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Evaluation of Dentin Desensitizing by Bioglass with Two Different Methods in Vitro. MA Qian, WU Feng-ming, LUO Rui, WANG Jie, CHEN Ya-ming. 2016, 32(12): 1287-1291.  DOI: 10.13701/j.cnki.kqyxyj.2016.12.015 Abstract ( 252 )   PDF (1285KB) ( 311 )   To evaluate the effect of bioactive glass desensitizer on dentinal tubule orifice occlusion through smearing or transparent pressure-swage. Methods: Fifty-six dentin slices were selected, and after demineralization, the slices were randomly divided into 7 groups: smearing the bioactive glass for 1 day, 3 days and 7 days (A1, A2, A3), applying the bioactive glass by pressure-swage for 1 day, 3 days and 7 days (B1, B2, B3) and negative control group. Occlusion effect on dentinal tubule orifice was observed via FESEM. Surface mineral content disparity of each dentin slices was analyzed by EDX. Results: FESEM results indicated that dentinal tubules were well occluded after smearing or transparent pressure-swage applying of bioactive glass desensitizer. The difference of dentinal tubule exposure between A1 and B1 was not significant different. The effect of dentinal tubule occlusion was better in B2 and B3 groups than in A2 and A3 groups. EDX results showed that Ca/P ratio on the dentinal surface in each group was not significantly different. Conclusion: Compared with smearing method, trans-parent pressure-swage method could improve the occlusion effect of dentinal tubules by bioactive glass in a short period of time. References | Related Articles | Metrics

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Evaluation of Micro-osteotomy Assisted Orthodontics Treatment on Alveolar Bone Dehiscence. WU Si-yuan, AI Yi-long, LIU Cheng-jun 2016, 32(12): 1292-1295.  DOI: 10.13701/j.cnki.kqyxyj.2016.12.016 Abstract ( 220 )   PDF (2294KB) ( 218 )   Objective: To quantitatively evaluate the effect of micro-osteotomy assisted orthodontic treatment on alveolar bone dehiscence in anterior teeth area. Methods: Eight patients with alveolar bone dehiscence in the anterior teeth area were selected to accept micro-osteotomy assisted orthodontic treatment in Foshan Stomatological Hospital from August 2014 to August 2015. The lower teeth periodontal status was evaluated at different stages by cone beam CT (CBCT). Data was processed using SPSS 21.0 software package. Results: There was no significant difference in the thickness and height of lingual alveolar bone before and six months after surgery, the thickness of the labial alveolar bone was significantly increased (P<0.05) and the height of the labial alveolar bone was significantly increased six months after surgery (P<0.05). Conclusion: Treatment effect on alveolar bone dehiscence in anterior teeth area was significant. With the application of micro-osteotomy assisted orthodontic technique, the height and thickness of the labial alveolar bone in the anterior teeth area increases significantly six month after surgery. References | Related Articles | Metrics

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Effect of Cements on Stress Distribution of All Ceramic Crowns at Central Incisors. YAN Jia-qun, ZHU Yan, WANG Tai-he, SU Hong. 2016, 32(12): 1296-1298.  DOI: 10.13701/j.cnki.kqyxyj.2016.12.017 Abstract ( 214 )   PDF (1038KB) ( 340 )   Objective: To investigate the effect of cements on the stress distribution of all ceramic crowns and agglomerants. Methods: CBCT images was used to construct the finite element analysis mode, including the core layer and the veneer layer of the crown, cement, tooth crown, tooth root, periodontal ligament and alveolar bone. 200N load was designed in three directions. The stress values of the veneer layer and the cement layer with different kinds of cements (3M Luting2, DMG PermaCem, and Kerr Maxcem elite) were analysed by ANSYS software. The equivalent stress (Von Mises stress) and the maximum principal stress (S1 stress) distribution were recorded. Results: The stress on the cement layer and the veneer layer were mainly concentrated around the loading point. With the increasing of elastic modulus of the cements, the Von Mises stress and the S1 stress on the cement layer was enhanced, but the von Mises stress and the S1 stress on the veneer layer was reduced. Conclusion: In the loading test, the Von Mises stress and the S1 stress on the all ceramic crown with different kinds of cements were tended to concentrate on the loading side. The cements with high elastic modulus may reduce the stress on the veneer layer of the crown. References | Related Articles | Metrics

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Effect of Ceramic Thickness on the Color Matching of Ceramic Veneers. XING Wen-zhong, ZHAN Kang-ru, Ren Da-fei, CHEN Xiao-dong. 2016, 32(12): 1299-1302.  DOI: 10.13701/j.cnki.kqyxyj.2016.12.018 Abstract ( 243 )   PDF (798KB) ( 342 )   Objective: To analyze the effect of ceramic thickness on the color matching of ceramic veneers. Methods: Thirty-six artificial teeth (right maxillary central incisors, A2 shade, Endura, Shofu, Japan) were prepared following the veneer preparation protocol. An improved lithium-disilicate pressed glass ceramic materials (A2 shade, HT and LT Blocks, IPS e.max Press, Ivoclar Vivadent) were used to fabricate the 0.50 mm, 0.75 mm and 1.00 mm thick veneers at the body section. The ceramic veneer specimens were bonded on the corresponding artificial teeth with resin cement (TR shade, RelyXTM Veneer, 3M, USA), respectively. The color parameters of ceramic veneer specimens were measured by a clinical spectrophotometer (Crystaleye, Olympus, Japan). The color differences (ΔE) of ceramic veneer specimens and A2 shade tab (Vita Classical Shade Guide, Vita Zahnfabrik, Germany) and C*ab values were calculated. Results: The ΔE values ranged from 2.17 to 6.60. The ΔE values were less than 3.3 at the body and cervical section of veneer when the 0.75 mm and 1.0 mm thick ceramic veneers were fabricated by HT blocks. Two-way ANOVA showed that the ΔE values were significantly affected by the ceramic thickness and the sections of ceramic veneers (P<0.001). Conclusion: The color parameters of ceramic veneers were significantly influenced by the ceramic thickness. With the increasing of ceramic thickness, the values of HT ceramic veneer specimens increased and the chroma values decreased. Moreover, LT veneers exhibited a higher chroma and lower brightness. References | Related Articles | Metrics

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Comparison of the Teeth between Ancient Human in Shimen County of Changde and Moden Human. SHI Jia-yi, TU Ling, LI Feng-hua. 2016, 32(12): 1303-1307.  DOI: 10.13701/j.cnki.kqyxyj.2016.12.019 Abstract ( 254 )   PDF (1583KB) ( 279 )   Objective: To compare the morphological structure of ancient human teeth found in Shimen County, Changde City, Hunan Province and modern teeth. Methods: Sound permanent ancient teeth were collected, and modern permanent teeth were selected following the principle: the same kind in same site. Morphological indexes, including the tooth length, crown length, root length, mesiodistal diameter of crown and cervix, labiolingual diameter of crown and cervix were recorded. The cross-section area of each tooth was measured. The data were statistically analyzed. Resluts: The crown length and root length of the ancient teeth are longer than that of modern teeth. In maxilla I1, P1, M1 and mandible I1, I2, C, P2, the differences were statistically significant (P<0.05). The mesiodistal diameter of crown and cervix, the labiolingual diameter of crown and cervix of ancient tooth were longer than that of moden ones. The cross-section area of the ancient tooth was larger than that of modern teeth but without significant differences. Conclusion: Ancient human teeth were significantly longer than modern teeth. References | Related Articles | Metrics

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Artificial Neural Network Assisted Selection of Extractionor Non-extraction Orthodontic Treatment for Malocclusion. HAN Lei, XIE Xiao-qiu, WANG A-ming, ZHAO Dan. 2016, 32(12): 1308-1311.  DOI: 10.13701/j.cnki.kqyxyj.2016.12.020 Abstract ( 230 )   PDF (1186KB) ( 263 )   Objective: To use artificial neural networks (ANN) to create a decision-making expert system (ES) for determining whether extraction is needed in the orthodontic treatment of malocclusion patients. Methods: A total of 230 subjects were examined, of which 138 underwent extraction treatment and 92 underwent non-extraction treatment. In each case, 28 indices were ex-amined. Data from 207 patients were aggregated to construct the training set, and data from the other 23 patients were used as the testing set. A Back Propagation (BP) ANN model was constructed using the MATLAB language to assist in evaluating the necessity for extraction. Results: When data from the training set were tested, the ES was 100% correct. When data from the testing set were submitted to the ES, the treatment plan was correctly fore-casted in 82.6% of the cases (i.e., only 4 cases failed). Conclusion: The constructed ANN was useful in determining whether extraction or non-extraction treatment should be employed in malocclusion patients. References | Related Articles | Metrics

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Application of Peri-auricle Positioning Method in Aesthetic Incision of Parotidectomy: A Clinical Study WANG Jun-lin, SONG Yong, LIU Yan-jie, CHEN Yu-cong. 2016, 32(12): 1312-1315.  DOI: 10.13701/j.cnki.kqyxyj.2016.12.021 Abstract ( 231 )   PDF (1616KB) ( 300 )   Objective: To investigate the feasibility of a peri-auricle positioning method in designing aesthetic incision of parotidectomy. Methods: Eleven patients with parotid benign tumor from April 2011 to May 2013 in our hospital were included. Peri-auricle positioning method was used to design incision of parotidectomy with preservation of facial nerve and great auricular nerve. Factors taken into the follow-up study included the cosmetic effect of the incision and the clinical outcome. Results: All surgeries, including 9 superficial parotidectomy and 2 total parotidectomy, were carried out successfully. All patients were satisfied with the aesthetic effect and the clinical outcome of this approach. Conclusion: Peri-auricle positioning is a simple, practical method that can gain satisfactory aesthetic result in parotidectomy. References | Related Articles | Metrics

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Short-term Effect of Two Nickel Titanium Motors on One-time Molar Root Canal Therapy. DU Chi, LUO Xiao-bing, ZHANG Fu-lan, Hong Fei. 2016, 32(12): 1316-1318.  DOI: 10.13701/j.cnki.kqyxyj.2016.12.022 Abstract ( 245 )   PDF (1587KB) ( 325 )   Objective: To observe the short-term effect of two nickel titanium motors, Protaper and Wave one, on one-time molar root canal therapy. Methods: Ninety teeth with pulpitis or asymptomatic nonvital teeth were randomly divided into 3 groups: group P (ProTaper for root canal preparation and warm gutta percha for immediately filling), W group (Wave one for root canal preparation and warm gutta percha for immediately filling), and group K (K file for root canal preparation and cold gutta percha for immediately filling). The curative effect and postoperative reaction of three groups were evaluated after one-time root canal treatment. Results: Ninety teeth was treated with one single root canal preparation and immediately filled. The pain of group P and group W within one week was significantly lower than that of group K. After 3 months and 6 months observation, the success rate of group P and group W was obviously higher than that of group K. The root canal preparation time was in the sequence of group W<group P<group K. Conclusion: The clinical efficacy of group P and group W was significantly better than that of group K, and the average preparation time of group W was shorter than that of group P. Nickel titanium motor has the advantages of saving time and high efficiency, and can reduce the postoperative reaction. References | Related Articles | Metrics

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Long-term Evaluation of Airway Changes by Cone-beam Computed Tomography in Patients with Skeletal Class Ⅲ Malocclusion Treated by Orthodontic-bimaxillary Surgery. YAN Ming, WANG Hong-wei, LI Li-yan 2016, 32(12): 1319-1322.  DOI: 10.13701/j.cnki.kqyxyj.2016.12.023 Abstract ( 261 )   PDF (1082KB) ( 332 )   Objective: To evaluate the long-term effects of orthodontic-bimaxillary surgery on pharyngeal airway in treating patients with skeletal Class Ⅲ malocclusion. Methods: Patients included in this study were 12 males and 14 females with skeletal Class Ⅲ malocclusion. The patients received LeFort I and bilateral split ramus osteotomies combined with orthodontic treatment. Cone-beam computed tomography was taken one week before, six months and three years after orthodontic treatment and the three dimensional model of pharyngeal airway was reconstructed. The sagittal and coronal diameter, cross section area, and the volume of the reconstructed pharyngeal airway were quantitatively measured. The data were statistically analyzed using SPSS version17.0. SNK test for variance analysis was conducted. Results: Six months after surgery, the sagittal diameter and cross section area at CV2, CV3 and CV4 planes significantly decreased(P<0.05), however they almost recovered to the preoperative level three years after surgery. Conclusion: Pharyngeal airway space decreased after the combined therapy in the short term and recovered to certain extent but not to the preoperative level in the long-term. References | Related Articles | Metrics

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Integration of Dental Restoration and Pulp Therapy of Left Mandibular First Molar With Four Curving Canals: Two Case Reports. YU Shuang, LIU Xue-jun, FAN Ming-wen. 2016, 32(12): 1323-1324.  DOI: 10.13701/j.cnki.kqyxyj.2016.12.024 Abstract ( 306 )   PDF (1197KB) ( 406 )   Integration of dental restoration and pulp therapy is the procedures of diagnosis, treatment plan, root canal treatment, dental restoration and following up completed by one dentist. This article describes two cases of integration of dental restoration and pulp therapy of left mandibular first molar with four curving canals. References | Related Articles | Metrics

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Application of Laser in Periodontal Non-surgical Treatment. XU Dan-ni, LIN Xiao-ping 2016, 32(12): 1325-1328.  DOI: 10.13701/j.cnki.kqyxyj.2016.12.025 Abstract ( 400 )   PDF (811KB) ( 344 )   Chronic periodontitis is an infectious disease caused by periodontal pathogens resulting in progressive loss of periodontal tissues and the alveolar bone. Mechanical method of removing dental plaque is one of the most effective methods for the treatment of periodontal disease. However, conventional therapy does not completely remove periodontal pathogens, especially the sites where conventional mechanical instrumentation cannot reach. In recent years, many researchers have studied the effect of laser in periodontal treatment. The following is the review about the application of laser irradiation in periodontal non-surgical treatment. References | Related Articles | Metrics

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Recording Methods and Appraisal Systems of Centric Relation. XIAO Shen-zhao, REN Guang-hui, LIU Zhong-hao. 2016, 32(12): 1329-1332.  DOI: 10.13701/j.cnki.kqyxyj.2016.12.026 Abstract ( 356 )   PDF (795KB) ( 717 )   Centric relation (CR) is the only stable position between maxilla and mandible. It is also a vital jaw relation during the reconstruction of a proper occlusion.CR is an important factor to occlusion, which is also closely related to prosthodontics, gnathology and orthodontics. CR has been a controversial subject for over a century. There is no consensus on the clear definition, the correct way to determine, and the appraisal method, which is very important for the clinical work. This review aims to review the controversial subjects mentioned above. References | Related Articles | Metrics