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Discussion on Pre-implantation Surgery Based on Distraction Osteogenesis Bone Augmentation LI De-chao, WANG Xin-yu 2019, 35(4): 313-315.  DOI: 10.13701/j.cnki.kqyxyj.2019.04.001 Abstract ( 276 )   PDF (1911KB) ( 225 )   The shortage of jaw bone is always the bottleneck that restricts the development of dental implantology. How to obtain stable and reliable implant base bone simultaneously before or during the implant surgery is also one of the focal points of the scholars. With the development of the research, a series of bone augmentation technics, such as guided bone regeneration, free bone graft, distraction osteogenesis, and maxillary sinus elevation, are more and more widely used. But the advantages and disadvantages of a single approach are also evident. Pre-implantation surgery with distraction osteogenesis as the main part will be discussed in this paper. References | Related Articles | Metrics

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Influence Factors of Building Fluorosed Rat Animal Models TAN Yu-jie, GUO Ling 2019, 35(4): 316-318.  DOI: 10.13701/j.cnki.kqyxyj.2019.04.002 Abstract ( 284 )   PDF (757KB) ( 312 )   Dental fluorosis is an endemic disease with high incidence rate in China. Rats are widely used for building animal models with dental fluorosis. However, there is no standardized method to set up these models. The present review discusses the methods of building animal models, strains of breeds, gender, age, and weight of rats, with aim to provide a modeling guidance of dental fluorosis. References | Related Articles | Metrics

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Research Progress on Accuracy of Adjoining Relationship between Mandibular Wisdom Tooth and Lower Alveolar Nerve QIN Li-ye,ZHOU Zhong-wei 2019, 35(4): 319-321.  DOI: 10.13701/j.cnki.kqyxyj.2019.04.003 Abstract ( 343 )   PDF (766KB) ( 367 )   Inferior alveolar never (INA) injury, one of the most serious complications of mandibular wisdom tooth extraction, is drawn widely prevalence for the severe influence on the quality of people life. In preoperative risk assessment of mandibular wisdom tooth extraction, panoramic radiograph is used as the first choice. However, the diagnostic accuracy of the adjoining relationship between mandibular wisdom tooth and inferior alveolar nerve has aroused many arguments at home and abroad. This review summarizes the diagnosis accuracy of panoramic radiography in describing the relationship between the two. References | Related Articles | Metrics

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Application of Paranasal Sinus Imaging in Forensic Identification YANG Xiao-fang, LI Bing 2019, 35(4): 322-324.  DOI: 10.13701/j.cnki.kqyxyj.2019.04.004 Abstract ( 270 )   PDF (770KB) ( 222 )   The main task of forensic anthropology is individual identification. Current methods include fingerprint analysis, DNA matching, palatal wrinkle, and iris contrast, which will be limited when the body is decomposed. The skeletal system is the last to decay after the death of the organism, and then, the enamel. As a result, forensic exports often analyze the skeletal remains of the bodies to make gender and individual identification. However, most skeletons have been found to be incomplete, which is not conductive to proper identification. Paranasal sinuses are oxygenated bone space, which is more resilient than other bones in the body. Therefore, they are often complete when there are major disasters, such as explosions, traffic accidents, and plane crashes, and often used for forensic identification. This paper summarizes the research achievements of scholars at home and abroad, and summarizes the research progress of paranasal sinus image used in the field of gender identification in forensic medicine. References | Related Articles | Metrics

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Application of 3D Printing in Oral Clinical Work WEI Yan, ZHANG Xiao-xin, XU Hu-di 2019, 35(4): 325-327.  DOI: 10.13701/j.cnki.kqyxyj.2019.04.005 Abstract ( 401 )   PDF (771KB) ( 490 )   In recent years, with the development of digital technology and engineering technology, 3D printing is successfully used to print a variety of personalized stents. For example, 3D print model and stent have been successfully used in the oral clinical work, and the restoration and implant are also popularized. The bone grafts printed with biocompatible materials also play an important role in oral surgery. In addition, 3D bioprinting with active ingredients, including cells, matrix, and growth factor, has shown remarkable development potential in tissue engineering and regeneration. This chapter covers 3D printing techniques and all recent research endeavors aiming to bring this novel therapeutic strategy to everyday clinical practice. References | Related Articles | Metrics

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Effect of Permeable Material on Penetration of Early Enamel Caries ZHANG Hao, SUN Wei-bin, MIAO Lei-ying, GE Jiu-yu 2019, 35(4): 328-330.  DOI: 10.13701/j.cnki.kqyxyj.2019.04.006 Abstract ( 223 )   PDF (1071KB) ( 236 )   Objective: To study the permeability of different permeable materials in the treatment of early enamel caries. Methods: Artificial caries model was established by demineralized liquid. The model was permeated by resin infiltration (group A), amorphous calcium phosphate agent resin (group B), and Single Bond 2 (group C). The penetration depth was measured by laser confocal microscopy to explore the treatment of early enamel caries. Results: The penetration depth of amorphous calcium phosphate agent resin (group B) was significantly higher than that of Single Bond 2 (group C), but lower than that of resin infiltration (group A). There was significant difference in the penetration depth between groups (P<0.05). Conclusion: Amorphous calcium phosphate agent resin can penetrate the enamel pores and forms a good surface sealing, however, it is different from the resin infiltration. References | Related Articles | Metrics

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Comparison of Different Kinds of Ni-Ti Instruments in Curved Root Canals JIANG Bo, HUANG Jing 2019, 35(4): 331-334.  DOI: 10.13701/j.cnki.kqyxyj.2019.04.007 Abstract ( 268 )   PDF (1660KB) ( 257 )   Objective: To evaluate the effect of curved canal preparation in posterior teeth using Protaper next (PN), Reciproc (R), Protaper next with Pathfile (PNP), and Reciproc with Pathfile (RP). Methods: From September 2016 to January 2018, eighty cases with curved canals of posterior teeth which need root canal therapy (RCT) were selected. The patients were randomly divided into four groups of 20 teeth each. The teeth canals were prepared using PN, R, PNP, and RP, respectively. All data including preparing time of root canals and Bias of root canals using CBCT to scan before and after preparation were recorded. Results: The group R spent the least time in preparation, and the average preparing time of four groups (PN, R, PNP, RP) were (48.46±25.72)s, (21.67±11.23)s, (93.64±28.56)s, and (71.23±18.78)s, respectively. Significant difference was found among four groups (P＜0.05). For severe degree curved root canals, compare the root canal deviation and the rates of axis center, difference was found between PN and PNP (P＜0.05), and between R and RP (P＜0.05). Conclusion: The PN and R are suitable for moderate degree curved root canals. When combined with Pathfile, these two instruments can result in significantly greater effect, especially in severe curved root canals. References | Related Articles | Metrics

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Angiogenesis of Stem Cells from Human Exfoliated Deciduous Teeth Stimulated by rhVEGF165 Loaded Catechol-chitosan YANG Xue, NI Shi-lei, WANG Ting-ting, HAN Jia-qi, ZHANG Lu-lu, GAO Hua-li, JIANG Qiu 2019, 35(4): 335-339.  DOI: 10.13701/j.cnki.kqyxyj.2019.04.008 Abstract ( 199 )   PDF (2712KB) ( 228 )   Objective: To study the effects of rhVEGF165 loaded catechol chitosan (cat-cs) scaffold on the angiogenesis of stem cells from human exfoliated deciduous teeth (SHED) in young permanent teeth. Methods: SHED was isolated and cultured by enzyme digestion and inverted adherent method. The stemness of SHEDs was identified by cell morphology, alkaline phosphatase, and alizarin red staining. The biocompatibility of CS and Cat-CS was detected by MTT, HE staining, and scanning electron microscope (SEM). The expression of endothelial cell marker CD31, VEGFR2, and VE-cadherin was detected by real-time PCR. Results: SHED had strong reproductive activity. Alkaline phosphatase and alizarin red staining revealed differentiation of SHED. The MTT results showed no obvious toxicity of Cat-CS to SHED. HE staining and SEM showed Cat-CS was more favorable for cell extension and adhesion. Cat-CS could efficiently promote more expression of CD31, VEGFR2, and VE-cadherin than CS. And the expression of these genes is further promoted when Cat-CS is combined with rhVEGF165 (P<0.05). Conclusion: Cat-CS has good biocompatibility and can be used as a good scaffold for pulp regeneration. References | Related Articles | Metrics

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Changes in Surface Morphology and Elements Composition of Orthodontic Bracket Before and After Treatment LIU Xiao-mo, ZHANG Meng-qi, LIN Jiu-xiang 2019, 35(4): 340-345.  DOI: 10.13701/j.cnki.kqyxyj.2019.04.009 Abstract ( 228 )   PDF (2990KB) ( 238 )   Objective: To analyze the surface topography and surface elements of two metal brackets after clinical application. Methods: The scanning electron microscope was used to observe the slot surface morphology before and after orthodontic treatment. X-ray energy-dispersive spectrometry was used to test the elemental composition of the surface. Results: After clinical use, traces of friction and wear and different plaque accumulation could be found on the bracket surface. However, the surface element did not change much. Conclusion: After exposure in mouth, the elemental composition on the metal surface changed little without significant ion deposition and release phenomenon. References | Related Articles | Metrics

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Effect of Twin Inclined Plane Appliance on Expression of Type Ⅱ Collagen and Vascular Endothelial Growth Factor in Condyle of Growing Rats WANG Shuo, HUA Xian-ming, SUN Yu-hong, XU Yan, XIA Lu-lu 2019, 35(4): 346-350.  DOI: 10.13701/j.cnki.kqyxyj.2019.04.010 Abstract ( 242 )   PDF (2437KB) ( 240 )   Objective: To investigate the effect of twin inclined plane appliance (TIPA) on the expression of type II collagen and vascular endothelial growth factor (VEGF) in condyle of growing rats. Methods: Male 6-week-old Wistar rats (n=48) were randomly divided into control group (n=16) and experimental group (n=32). Rats in experiment group wore TIPA, whereas for the control groups no appliances were fitted. After 3, 14, 30, and 60 days, the rats were euthanatized and samples were collected. Immuohistochemical method was used to localize and examine the type II collagen and VEGF in the posterior area of mandibular condylar cartilage (MCC). Results: The expression of type II collagen decreased significantly on day 30 and reached the lowest on day 60 in the experimental group (P<0.01). The expression of VEGF increased significantly on day 30 (P<0.05) and reached the peak on day 60 in the experimental group (P<0.01). Conclusion: Both type II collagen and VEGF take part in MCC remolding during the gradually induced backward movement of mandible induced by TIPA. References | Related Articles | Metrics

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Comparative Study on Vertical Effect between Miniscrew and Face-bow in Orthodontic Treatment of Hyperdivergent ClassⅡ Protrusion DING Shao-hua, LIU Ming-hai , ZOU Ting-qian 2019, 35(4): 351-354.  DOI: 10.13701/j.cnki.kqyxyj.2019.04.011 Abstract ( 238 )   PDF (770KB) ( 341 )   Objective: To compare the vertical effect between infrazygomatic crest high planting miniscrew combined with horizontal palatal bar and high headgear face-bow combined with horizontal palatal bar in the treatment of hyperdivergent classⅡ protrusion. Methods: Twenty patients with hyperdivergent classⅡ protrusion were randomly divided into two groups with 10 cases in each group. The control group adopted high headgear face-bow + horizontal palatal bar + straight wire technology, and the experimental group adopted infrazygomatic crest high planting miniscrew + horizontal palatal bar + straight wire technology. Maxillary anterior teeth were retracted by sliding method to close the extraction spaces for two groups. Lateral cephalometric films were taken pre and post orthodontic treatments. Vertical parameters of teeth and skeleton were analyzed by measuring the cephalogram pre and post treatments. Results: Statistically significant differences were existed on vertical parameters (SN-MP°, N-Me, N-SGn°, U6M-PP) measurements between two groups or pre and post orthodontic treatments in experimental group. There was no statistically significant difference between all the parameters of the control group and UO-PP of the experimental group pre and post treatments, the anterior teeth were lowered by 0.4mm on average in the experimental group, reversely elongated by 0.5mm on average in the control group, but there was no significant difference between two groups. Conclusion: Infrazygomatic crest high planting miniscrew combined with palatal bar in the treatment of hyperdivergent classⅡ protrusion could depress the maxillary molars, as well as a little press down maxillary anterior teeth, which could gain better effect for vertical skeletal pattern. References | Related Articles | Metrics

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Clinical Research on Surgical Treatment of Condylar Fractures by Retromandibular Incision from Anteroparotid Approach YANG Shuang-lin, ZHAO Wen-jie, SUN Li-bo, WU Shuang-jiang, FU Guang-xin, XIAO Jin-gang 2019, 35(4): 355-359.  DOI: 10.13701/j.cnki.kqyxyj.2019.04.012 Abstract ( 195 )   PDF (2774KB) ( 193 )   Objective: To compare postoperative curative effects of condylar fractures by anteroparotid approach and transparotid approach of retromandibular incisions. Method: This study consisted of 52 cases with condylar fractures treated at the Affiliated Stomatology Hospital of Southwest Medical University between January 2013 and June 2017. Fifty-two cases were randomly divided into modified incision group and control group. The patients of the modified incision group with condylar fractures accepted surgical treatment by the anteroparotid of retromandibular incisions, while the patients of the control group with condylar fractures accepted surgical treatment by the transparotid approach of retromandibular incisions. During the follow-up period of 6-36 months, the curative effects were evaluated based on operation time, fracture restoration, mouth opening, occlusion relationship, facial nerve injury, and salivary fistula. Results: Modified incision group: the average operation time was 79.60 min; all patients recovered well in fracture restoration, mouth opening and occlusion relationship; 1 case of temporary facial nerve injury occurred;and no case of salivary fistulas occurred. Control group: the average operation time was 86.40 min; all patients recovered well in fracture restoration, mouth opening and occlusion relationship; facial nerve injuries happened in 6 cases, 1 of which was permanent and 5 of which were temporary facial nerve injuries; 4 cases had postoperative salivary fistulas. Conclusion: Compared with the traditional transparotid approach of retromandibular incisions, the anteroparotid approach of retromandibular incisions effectively reduced the intraoperative facial nerve injury and postoperative salivary fistulas in the treatment of condylar fractures by opening reduction and internal fixation. Moreover, it shortened the operation time, and did not increase the incidence of other complications. Therefore, it was worthy of clinical expansion. References | Related Articles | Metrics

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Expression of LncRNA FAL1 in Oral Squamous Cell Carcinoma and Its Relationship with Prognosis BAI Zhen-yu, WANG Kai, LIU De-yu, HUANG Xie-shan 2019, 35(4): 360-363.  DOI: 10.13701/j.cnki.kqyxyj.2019.04.013 Abstract ( 183 )   PDF (838KB) ( 215 )   Objective: To investigate the expression of long-chain non-coding RNA (LncRNA) FAL1 in oral squamous cell carcinoma (OSCC) and its relationship with prognosis. Methods: Ninty-five patients with OSCC admitted to Haikou People's Hospital and Xiangya No.2 Hospital of Central South University from January 2013 to May 2015 were enrolled in this study. The OSCC tissues surgically resected were set as OSCC group, and oral mucosal tissues of 50 healthy people were set as control group. Real time quantitative PCR was used to detect the expression level of LncRNA FAL1 in the two groups. The clinicopathological data of patients were collected. According to the median value of LncRNA FAL1 expression, OSCC group was divided into low expression group and high expression group. The relationship between the expression of LncRNA FAL1 and clinicopathological characteristics was analyzed. Kaplan-Meier method was used for survival analysis. Log-Rank method was used to examine the effect of LncRNA FAL1 expression on prognosis. Cox was used to analyze the related factors affecting OSCC. Results: The expression of LncRNA FAL1 in OSCC group was significantly higher than that in control group (P<0.05). LncRNA FAL1 was significantly correlated with clinical stage, T stage, differentiation degree, and lymphatic metastasis (P<0.05). Kaplan-Meier survival analysis showed that PFS and OS in LncRNA FAL1 low expression group were significantly higher than those in LncRNA FAL1 high expression group (P<0.05). Cox analysis showed that clinical stage, T stage, degree of differentiation, and lymphatic metastasis were all risk factors for OSCC. Conclusion: LncRNA FAL1 is highly expressed in tissues of patients with OSCC, and it may be closely related to the occurrence, development, and prognosis of OSCC. References | Related Articles | Metrics

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Application of 99Tcm-RBC SPECT in Diagnosis of Maxillofacial Vascular Malformations LIU Hong-wei, HUANG Cheng-ming, AN Lin 2019, 35(4): 364-367.  DOI: 10.13701/j.cnki.kqyxyj.2019.04.014 Abstract ( 161 )   PDF (1506KB) ( 181 )   Objective: To evaluate the application of 99Tcm-RBC blood pool scintigraphy in diagnosis of maxillofacial vascular malformations. Methods: Forty patients with clinically suspected maxillofacial vein malformations were examined by 99Tcm-RBC blood pool scintigraphy and the results were compared with MRI. The chi-square test was used to compare the significance. Results: The sensitivity, specificity, and accuracy of 99Tcm-RBC blood pool scintigraphy in diagnosis of maxillofacial vein malformations were 97.50%, 100.00%, and 100.00%, respectively. Thirty-nine of 40 patients who had maxillofacial vein malformations showed positive images (97.50%), and 1 patients showed false positive images (2.50%); 33 of 40 patients by MRI who had malignant tumors showed positive image (82.50%), and 7 patients showed negative image (7.50%). There was a significant difference between two groups by the chi-squre test (P＜0.05). Conclusion: It is suggested that 9Tcm-RBC blood pool scintigraphy can be used in diagnosis of maxillofacial vein malformations. References | Related Articles | Metrics

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Evaluation of Piezoelectric Bone Knife in Extraction of Rupture Root of Mandibular Third Molar HE Ping, FENG Yu, WU Xiao-le, LI Ji-yin, ZHANG Lu-ye, CHEN Xiao-dong 2019, 35(4): 368-371.  DOI: 10.13701/j.cnki.kqyxyj.2019.04.015 Abstract ( 228 )   PDF (1620KB) ( 249 )   Objective: To compare the clinical effects of ultrasonic bone knife and chisel in extraction the broken root of mandibular third molars. Methods: A total of 200 patients with root fractures of mandibular third molar were enrolled from 2017,1 to 2018,1. The patients were randomly divided into the traditional group (99 cases) and the experimental group (101 cases). Both groups were treated with minimally invasive extraction before root fracture. Conceptual technology, the traditional group of conventional bone-cutting method was used to remove the root after root-cutting. The experimental group used the super-bone knife to remove the root, and statistical analysis was performed on the operation time and complications of two groups. Results: The time of the traditional group was (13.11±2.14) min, and the experimental group was (19.57±3.11) min. The root withdrawal time of the experimental group was longer than that of the traditional group (P<0.05), and the roots were completely removed after operation. There was no vascular nerve injury in the experimental group, and there were 24 cases of nerve injury in the traditional group. In the traditional group, 8 cases had lingual bone plate fracture, and 3 cases were broken into the sublingual, submandibular, and parapharyngeal spaces. The postoperative complications in the experimental group were lower than those in the traditional group (P<0.05). Conclusion: Ultrasonic osteotome, when removing the root of the mandibular third molar, significantly reduces the intraoperative and postoperative complications. The piezoelectric bone knife has good clinical significance. References | Related Articles | Metrics

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Effects of Periodic Compression on Expression of Pro-osteoclastic Factors by Mandibular Condylar Chondrocytes RUAN Guo-xian, GAO Li-qing, DENG Li 2019, 35(4): 372-376.  DOI: 10.13701/j.cnki.kqyxyj.2019.04.016 Abstract ( 189 )   PDF (2183KB) ( 245 )   Objective: To investigate the effects of periodic compression on the expression of pro-osteoclastic factors by mandibular condylar chondrocytes (MCCs). Methods: The rat MCCs were isolated and mixed with agarose culture medium. The Flexcell system was used to conduct compression on the MCCs/agarose mixture. The intensities of compression were 15, 30, and 45 kPa (frequency 0.5 Hz), and the stimulating time were 2, 6, and 12 hours. The control group was treated in the same way but without compression. Cells were collected after the application of force and the expression of pro-osteoclastic factors by MCCs were detected. Results: When the MCCs were stimulated by 15 kPa compression for 6 hours, the expression of RANKL was significantly higher than those of the controls. When the MCCs were stimulated by 30 and 45 kPa compression for 6 and 12 hours, the expression of SDF-1, TGF-beta-1, and RANKL were higher than those of the controls, but the gene expression of MCP-1, M-CSF, and OPG were not different from those of the controls. Conclusion: Periodic compression could promote the expression of pro-osteoclastic factors such as SDF-1, TGF-beta 1, and RANKL. References | Related Articles | Metrics

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Experimental Study on Repair of Critical-size Calvarial Defects in Osteoporotic Rats by Biphasic Calcium Phosphate Ceramic Scaffold PENG Shuang-lin, YAO Zhi-hao, LUO Dao-wen, YANG Shuang-lin, LI Yong, XIAO Jin-gang 2019, 35(4): 377-381.  DOI: 10.13701/j.cnki.kqyxyj.2019.04.017 Abstract ( 225 )   PDF (2670KB) ( 310 )   Objective: To study the effect of the biphasic calcium phosphate ceramic scaffold (BCP) on the repair of critical-size calvarial defects in SD rats with osteoporosis. Methods: SD rats were made into critical-size calvarial defects with osteoporosis. BCP was used to repair the defect of the skull. The rats were divided into four groups, i.e. the Ctrl group, the OP group, the Ctrl+BCP group, and the OP+BCP group. Rats in each group were sacrificed 8 weeks later and the differences in bone formation were detected by imaging findings (Micro-CT) and histological manifestations (Masson staining and hematoxylin-eosin staining). Results: No obvious new bone was found in the Ctrl group and the OP group. New bone can be found in the Ctrl+BCP group and the OP+BCP group, and the new bone in the OP+BCP group was significantly less than that in the non-osteoporosis group (the Ctrl+BCP group). Conclusion: BCP can be used as the scaffold for the repair of critical-size calvarial defects in SD rats with osteoporosis, but the repair effect is weaker than that of normal SD rats. References | Related Articles | Metrics

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Failure Mode of Porcelain Laminate on Prepared and Unprepared Anterior Teeth YIN Lu, ZHENG Yan-fen 2019, 35(4): 382-385.  DOI: 10.13701/j.cnki.kqyxyj.2019.04.018 Abstract ( 206 )   PDF (1399KB) ( 186 )   Objective: To investigate the failure mode of porcelain laminates on prepared- and unprepared- anterior teeth in order to compare their longevity and success rate. Methods: Thirty extracted maxillary central incisors were randomly divided into 3 groups regarding their preparation methods. The preparation methods were full-preparation (group A), full-preparation and finishing with fine diamond bur (group B), and no-preparation, only grinding with diamond bur (group C). After conditioning the teeth, ceramic veneers (IPS e.max) were silanated and then cemented with DuoLink luting cement. The shear bond strength was measured for each group and failure mode was determined by stereomicroscopic examination. Results: Group C exhibited the highest shear bond strength. The shear bond strength was significantly different between groups C and B (P< 0.05). However, the difference between group A and C was insignificant, as was the difference between group A and B (P>0.05). Adhesion failure mode was found to be more common than the cohesive mode. Conclusion: Regarding the failure mode of unprepared anterior teeth to porcelain laminate veneers yielded by this study, no-preparation veneers might be used when the enamel is affected by wearing, trauma, or abrasion. It can also be used in patients who refuse the treatments which involve tooth reduction and preparation. References | Related Articles | Metrics

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Formula Design of Eucommia Ulmoides Gum Composite Soft Denture Liners LUO Heng, GAO Hai, XU Xue-fei, FENG Yun-zhi 2019, 35(4): 386-389.  DOI: 10.13701/j.cnki.kqyxyj.2019.04.019 Abstract ( 173 )   PDF (889KB) ( 313 )   Objective: To prepare a soft lining material with high elastic on the basis of excellent characteristics of eucommia ulmoides gum. Methods: The basic formula was used based on the existing formula of elastic eucommia ulmoides gum and medical rubber. The current formula was modified according to the specific requirements of denture lining materials. Corresponding eucommia ulmoides gum composite soft denture liners were constructed and delivered to physical and mechanical property tests. Subsequent modification to the formula was made according to the results of tests. The "modification and test" procedure was repeated, until favorite formula was established. Results: When eucommia ulmoides gum and butadiene rubber blend ratio was 80∶20, after adding gas phase nano-silica with 7PHR and appropriate content of fillers, eucommia ulmoides gum composite soft denture liners could present favorite properties. Conclusion: The final formula of eucommia ulmoides gum composite soft denture lining material was established by the "modification and test" procedure. References | Related Articles | Metrics

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Effect of Mixing Time and Powder-water Ratio on Flowability of Alginate Impression Material SU Yu-di, ZHANG Yu-ying, ZHANG Jin-ling, CHEN Xiao--mei, ZENG Yan-ping, LU Zhao-jie, LIN Jie 2019, 35(4): 390-392.  DOI: 10.13701/j.cnki.kqyxyj.2019.04.020 Abstract ( 325 )   PDF (792KB) ( 287 )   Objective: To compare the effects of three powder-water ratios and four mixing times on the flowability and accuracy of alginate impression by automatic mixing. Methods: The alginate impression material was mixed by automatic alginate mixer. The fluidity and accuracy were measured by 12 combinations of 3 powder-water ratios (11.5 g:23 mL, 11.5 g:25 mL, 11.5 g:27 mL) and 4 mixing times (3 s, 6 s, 9 s, 12 s). Results: The powder-water ratio and mixing time had significant effect on the flowability of impressions (P < 0.01). The 23mL12s group had the lowest fluidity [(43.05±3.43) mm] and the 27mL3s group had the highest [(72.31±2.25) mm]. The influence of powder-water ratio and mixing time on the accuracy of impression materials was not statistically significant. Conclusion: In a certain range, the powder-water ratio and mixing time were negatively correlated with the flowability of alginate impression materials, and the effect of increasing water content on the flowability was more obvious than that of decreasing water content. References | Related Articles | Metrics

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Expression and Clinical Significance of α-SMA in Different Clinical Subtypes of Oral Lichen Planus WANG Ya-min, MENG Wen-xia, ZHOU Zhen, GUO Wei,XIE Bao-yi 2019, 35(4): 393-396.  DOI: 10.13701/j.cnki.kqyxyj.2019.04.021 Abstract ( 223 )   PDF (2988KB) ( 270 )   Objective: To assess the expression of α-smooth muscle actin(α-SMA)and its clinical significance in oral lichen planus. Methods: Fifteeen cases of normal control, 22 cases of oral lichen planus, and 15 cases of oral squamous cell carcinoma were enrolled in the study. Immunohistochemical analysis was used to detect the expresssion level of α-SMA. Results: The expression level of α-SMA in erosive oral lichen planus, nonerosive oral lichen planus, and oral squamous cell carcinoma were higher than that in nomal control (P＜0.05). The expression level of α-SMA in OSCC was higher than that in OLP (P＜0.05). There was no statistical difference between erosive and nonerosive oral lichen planus (P=0.279). Conclusion: High expression of α-SMA was related to oral lichen planus and OSCC, which may be involved in the malignant transformation of oral lichen planus. References | Related Articles | Metrics

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IGF1-PI3K/mTOR Pathway Has Regulatory Effects on Cytokines in T cells and Keratinocytes Co-culture System MA Rui-jie, TAN Ya-qin, ZHOU Gang 2019, 35(4): 397-400.  DOI: 10.13701/j.cnki.kqyxyj.2019.04.022 Abstract ( 221 )   PDF (853KB) ( 202 )   Objective: To investigate the influence of IGF1-PI3K/MTOR signaling pathway, which was abnormally activated in OLP, on the inflammatory cytokines in the interaction of T cells and keratinocytes in oral lichen planus (OLP). Methods: A transwell co-culture system composed of T cells and oral keratinocytes was used as a model of OLP in vitro. The effects of activated T cells pretreated with LY294002, rapamycin, and IGF1 on the levels of IL-2 and TNF-α in supernatant from T cell alone and co-culture system were detected via ELISA, respectively. Results: Compared to the T cells cultured alone, the interaction of keratinocytes and T cells could increase the secretion of TNF-α (P<0.05), but has no impact on the level of IL-2. Whereas the aberrant IGF1-PI3K/MTOR signaling decreased the IL-2 and TNF-α secretion in the co-culture system (P<0.05). Conclusion: The IGF1-PI3K/MTOR signaling may modulate the cytokine networks in the crosstalk between T cells and keratinocytes and participate in the progression of OLP. References | Related Articles | Metrics

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Effects of Bone Marrow Mesenchymal Stem Cells Derived Exosomes on Proliferation and Differentiation of Osteoblasts CHEN Yan, JIANG Sheng-jun, PENG You-jian 2019, 35(4): 401-404.  DOI: 10.13701/j.cnki.kqyxyj.2019.04.023 Abstract ( 283 )   PDF (2056KB) ( 235 )   Objective: To evaluate the effects of bone marrow mesenchymal stem cells (BMSCs) derived exosomes on the proliferation and differentiation of osteoblasts. Methods: BMSCs were cultured in vitro and exsomes were isolated by ultracentrifugation from supernatants. After treated with BMSCs derived exosomes, the proliferation of osteoblasts was detected by CCK-8 assay. Alkaline phosphatase activity (ALP) analysis and alizarin red staining were adopted to evaluate the effect of BMSCs derived exosomes on mineralization process of osteoblasts. Real-time PCR was utilized to detect the expression of odontogenesis-related genes. Results: BMSCs derived exosomes enhanced the proliferation of osteoblasts and upregulated the expression levels of odontogenesis-related genes. The ALP activity and calcium accumulation of osteoblasts were increased significantly as well. Conclusion: BMSCs derived exosomes could promote the proliferation and differentiation of osteoblasts. References | Related Articles | Metrics

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Biomechanical Properties of Polyetheretherketone Prostheses Prepared by Three Different Processes GUO Fang, HUANG Shuo, ZHU Yong, XUE Yang, HU Min, GAO Yue-rong, LIU Chang-kui 2019, 35(4): 405-408.  DOI: 10.13701/j.cnki.kqyxyj.2019.04.024 Abstract ( 242 )   PDF (1149KB) ( 237 )   Objective: By testing the biomechanical properties of three different processes PEEK standard parts, to evaluate the advantages and clinical application prospects of 3D printing PEEK prosthesis. Methods: Standard parts for biomechanical testing were manufactured by three processes: isomer (injection molding), reduction (machining) and augmentation (3D printing). Uniaxial tensile test, uniaxial compression test, and three-point bending test were carried out to test the biomechanical properties of the standard parts. LSD test was used to compare the mean values among groups. Results: There was no significant difference in tensile strength between 3D printing specimens and mechanical processing and injection molding. The bending strength of 3D printing was slightly lower than that of mechanical processing, but not significant different from that of injection molding. Conclusion: The polyetheretherketone prosthesis prepared by 3D printing technology has better mechanical properties and can better meet the individualized clinical needs. References | Related Articles | Metrics

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Implant Restoration for Consecutive Multiple Tooth Loss in Aesthetic Area: A Case Report WANG Chun-yang, CUI Yun-xia, QUAN Xu, LI Yu-yang, HAN Chun-yu, FU Qi-jue, MENG Wei-yan 2019, 35(4): 409-410.  DOI: 10.13701/j.cnki.kqyxyj.2019.04.025 Abstract ( 312 )   PDF (1261KB) ( 459 )   Implantation restoration is more and more applied to dental defect and tooth loss, but it is still difficult to repair the continuous loss of multiple teeth in aesthetic area. In this case, the method to restore the aesthetics and function of continuous loss of maxillary anterior teeth is discussed. References | Related Articles | Metrics