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Association between Jak2 and Stat3 Expression in Experimental Induced Rat Periapical Lesions. AO Xiang, Wang Li-na, Wang Jiao-jiao, Ye Dan-dan, Ding Yin-hao, Qu Wen-shu, Niu Wei-dong 2017, 33(1): 1-5.  DOI: 10.13701/j.cnki.kqyxyj.2017.01.001 Abstract ( 420 )   PDF (3137KB) ( 331 )   Objective: To investigate the expression of Jak2/Stat3 pathway in induced rat inflammatory periapical lesions. Methods: Pulps of right mandibular first molars of twenty-five 8-week-old SD rats were exposed with PBS cotton ball. Then the molars were filled with glass ionomer and occulsal relationship was adjusted. The rats were then randomly sacrificed after 0, 7, 14, 21 and 28 days. The lower jaws were isolated and prepared for histologic, immunohistochemical, and enzyme histochemical analysis. Results: The model of apical periodontitis by PBS was successfully induced. The number of Jak2, Stat3, P-Jak2 and P-Stat3 positive cells was higher in periapical lesions compared with normal root apices (P＜0.05), and peaked at 14 days and decreased at 21 days (P＜0.05). On 28 days, the expressions of Stat3, P-Jak2 and P-Stat3 in the experimental group were almost the same as those of the control group (P＞0.05). However, the expression of Jak2 was still higher than that in the control group (P＜0.05). The formation of osteoclasts in the experimental group increased after 7 days, reached the maximum after 14 days and decreased after 21 and 28 days in contrast to that of the control group (P<0.05). The expression of Jak2/Stat3 was found synchronous with osteoclast formation. Conclusion: These findings suggest that Jak2/Stat3 pathway may play an important role in the periapical periodontitis and contribute to the initiation of periapical bone destruction. References | Related Articles | Metrics

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Effects of ALK2 on the Proliferation and Differentiation of Condylar Chondrocytes in Mice ZHANG Qi, ZHANG Xue, ZHAO Liang, HU Yue, SHI Ce, SUN Hong-chen, HUANG Yang 2017, 33(1): 6-9.  DOI: 10.13701/j.cnki.kqyxyj.2017.01.002 Abstract ( 295 )   PDF (1591KB) ( 318 )   Objective: To study the effect of ALK2 on the proliferation and differentiation of mice condylar chondrocytes. Methods: Condylar chondrocytes (MCC) were obtained by enzyme digestion. Immunocytochemistry and real-time PCR were used to identify the isolated cells. SiRNA was used to silence the expression of Alk2 gene in MCC in vitro. Cell proliferation was determined by MTT. The expression of cartilage cell marker genes was analyzed by real-time PCR. Results: Immunocytochemical staining showed strong positive expression of COL I and AGGRECAN, and weak positive expression of COL II. Real-time PCR results showed that the expressions of cartilage related genes such as COL I, COL II, COL X were increased. After silencing ALK2, MTT results showed that cell number was increased and the expression of cartilage related genes was significantly down-regulated. Conclusion: ALK2 could inhibit the proliferation of MCC and promote the chondrogenic differentiation of MCC. References | Related Articles | Metrics

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Study on Mice’S Immune Response in Vivo after Dental Pulp Stem Cells Allogeneic Transplantation. ZHANG Miao, LI Bo-qi, ZHENG Li-zhu, LIU Yi-shan. 2017, 33(1): 10-14.  DOI: 10.13701/j.cnki.kqyxyj.2017.01.003 Abstract ( 285 )   PDF (3430KB) ( 208 )   Objective: To explore the systemic immune response of mice after dental pulp stem cells (DPSCs) allogeneic transplantation. Methods: Dental pulp stem cells were isolated from C57BL/6 mice’s pulp, cultured to the third generation in vitro, and then cultured together with the nanometer hydroxyapatite into a composite. Scanning electron microscope was used to observe the growth condition of the composites. Forty C57BL/6 mice of four weeks were randomly divided into experimental group and control group. The experimental group mice were transplanted the composite under the skin of upper back. And the control group mice were transplanted nanometer hydroxyapatite under the skin of upper back. Two groups of animals were observed 4 and 6 weeks, respectively. The splenic cells of mice were prepared by a stainless steel mesh. Flow cytometry instrument was used to measure the value of CD4+ and CD8+. Results: Dental pulp stem cells were well bonded with nanometer hydroxyapatite in vitro. Immunohistochemical study showed that both 4 weeks and 6 weeks experimental groups had positive expressions of the dentin sialoprotein (DSP). After 4 and 6 weeks, the values of CD4+ and CD8+ had no obvious differences between the experimental group and the control group. Conclusion: The results of our experiments proved that after allogeneic transplantation of dental pulp stem cells, it is impossible to cause the body's immune rejection. Dental pulp stem cells still have low immunogenicity in vivo, which are expected to be a source of allograft tissue engineering seed cells in the future. References | Related Articles | Metrics

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Effect of Radiotherapy on Microvascular Injury of Parotid, Submandibular and Sublingual Gland in Minipig. YAN Xing, WU Hong-yi, XU Nuo, MENG Cen 2017, 33(1): 15-18.  DOI: 10.13701/j.cnki.kqyxyj.2017.01.004 Abstract ( 241 )   PDF (1951KB) ( 262 )   To observe the microvascular injury of parotid, submandibular and sublingual gland under radiotherapy in minipig. Methods: Six minipigs were divided into two groups (n=3), which were treated by radiotherapy at 0 Gy or 20 Gy at bilateral parotid, submandibular and sublingual glands. After radiotherapy for 4 hours, the minipigs were euthanatized, while their parotid, submandibular and sublingual glands were collected for hematoxylin-eosin (HE) staining and immunohistochemical staining of CD31. Results: There were significant difference in CD31 positive staining between these two groups and among three glands (P<0.05). In addition, CD31 positive staining showed significantly differents between parotid with submandibular or sublingual gland (P<0.05), but no differences were detect beween between submandibular and sublingual gland. Conclusion: Radiotherapy can decrease the microvascular density in the parotid, submandibular and sublingual glands of minipig, but the decreased extent in these glands were different, which in parotid is the most obvious. References | Related Articles | Metrics

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Degradation of Polylactic Acid/hydroxyapatite CompositePrimary Teeth Post in Vitro. ZHANG Lu-lu, GAI Li-ting, XU Gao-xiang, YANG Xue, GAO Hua-li, JIANG Qiu. 2017, 33(1): 19-23.  DOI: 10.13701/j.cnki.kqyxyj.2017.01.005 Abstract ( 272 )   PDF (2101KB) ( 306 )   Objective: To evaluate the degradation in vitro of polylactic acid/hydroxyapatite (PLA/HA) compositesprimary teeth post. Methods: According to the Chinese standard for biological evaluation of medical devices, the PLA/HA and PLA were immersed in phosphate buffer liquid (PBS) and distilled water, and a series of tests were performed with specimens in vitro at different time points respectively to evaluate the degradation in vitro of PLA/HA. Results: Macroscopic observation showed that the specimen color turned to white gradually and appeared micro cracks. The SEM results showed that the HA particles became smaller and PLA appeared sizes pore with the extension of degradation time. The molecular weight of PLA/HA and PLA decreased gradually and its elastic modulus and bending strength attenuated. The pH values of PLA/HA and PLA degradation solutions reduced gradually and that of PLA was falling faster than that of PLA/HA. Conclusion: The PLA/HA has a certain degradation performance, and its mechanical strength can keep primary teeth bite force in the ten months of observation. References | Related Articles | Metrics

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Expression of iNOS and COX-2 in Synovial Membrane of Rat with Altered Anterior Guidance. YAO Tian-hua, LI Yu-xuan, TAN Wen-hong, HAN Hui-fang, ZHAI Tong, BAI Le-kang, XIAO Min 2017, 33(1): 24-28.  DOI: 10.13701/j.cnki.kqyxyj.2017.01.006 Abstract ( 304 )   PDF (1287KB) ( 237 )   Objective: To investigate effects of experimentally altered anterior guidance on the expression of cyclooxygenase-2 (COX-2) and inducible nitric oxide synthase (iNOS) in temporomandibular joint synovium of rats. Methods: Anterior guidance deletion model was induced by eliminating the contact between anterior teeth in every direction with a diamond wheel. The anterior guidance accretion models were accomplished by cemented metal crowns which gained 15 and 30 degree on palatal side to the incisors of rats’ maxilla. Two animals in each group were sacrificed after 3, 7, 14, and 28 days. The complete TMJ of one side and TMJ synovium of the other side were obtained for analysis of iNOS and COX-2 expression by immunohistochemistry (IHC) and real-time polymerase chain reaction analysis (real-time PCR). Results: The anterior guidance in 30 degree group (group T3) showed statistical differences when compared with control group (group C) in COX-2 and iNOS mRNA expression 基金项目 陕西省社会发展科技攻关基金(编号:2012k16-10-03) 作者简介 姚天华(1976~ ),女,河南人,硕士,主治医师, 主要从事口腔综合类研究。 李雨轩(1988~ ),女,陕西人,硕士,医师,主要研究方向为牙合学与颞下颌关节紊乱病。 *通讯作者 肖敏,电话:029-87218541 #为共同第一作者 (P<0.05). In group T3, the level of COX-2 reached the highest on day 3 and there was statistical difference among specimens sacrificed after 3d, 7d and 28d (P<0.008). iNOS expression peaked on day 7, but showed no statistical differences compared with those of day 3, 14, and 28. Conclusion: COX-2 and iNOS may be involved in TMJ synovitis caused by altered anterior guidance. References | Related Articles | Metrics

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Effects of Dicalcium Silicate on Murine RAW 264.7 Macrophage Cell Line. LAI Shi-xiang, CHEN Liang-jiao, CAO Wei, ZHANG Qing-bin, CUI Shi-man, LI Xing-yang 2017, 33(1): 29-32.  DOI: 10.13701/j.cnki.kqyxyj.2017.01.007 Abstract ( 272 )   PDF (1466KB) ( 251 )   Objective: To investigate the proinflammatory response of dicalcium silicate on murine RAW 264.7 macrophage cell line. Methods: qRT-PCR method was used to determine the effects of dicalcium silicate and tricalcium phosphate particles on expressions of TLR2 and TLR9 co-cultured with RAW264.7 for 6 h and 24 h. Results: Scanning electron microscope revealed that RAW264.7cells phagocytosed both dicalcium silicate and tricalcium phosphate particles. Compared with tricalcium phosphate particle group, TLR2 and TLR9 showed no obvious change in dicalcium silicate particles group when co-cultured with RAW264.7 for 6 h. For 24 h, the expression of TLR2 in dicalcium silicate particle group was obviously higher (P<0.001), and the expression of TLR2 was also increased in 10 mg/L tricalcium phosphate group (0.05<P<0.1). Conclusion: TLR2 may be involved in the proinflammatory response of dicalcium silicate murine RAW 264.7 macrophage cell line. References | Related Articles | Metrics

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Expressions of PLAP-1 and BMP-2 in Periodontal Tissue of Rat during Orthodontic Tooth Movement ZHOU Cong, WU Bao-qin, ZHU Zhong-yan, TAN Hong 2017, 33(1): 33-37.  DOI: 10.13701/j.cnki.kqyxyj.2017.01.008 Abstract ( 222 )   PDF (1917KB) ( 345 )   Objective: To examine the expression of periodontal ligament-associated protein-1 (PLAP-1) and bone morphogenetic protein-2 (BMP-2) in the periodontal tissue of rats during the orthodontic tooth movement. Methods: A total of 36 male SD rats were allocated into 6 groups evenly, d1, d3, d5, d7, d14, d21. The power of 50g was applied on the left maxillary first molar, and the distance of orthodontic tooth movement was measured on the different time. HE staining and immunohistochemical sp method were used to detect the morphological changes, the expression of PLAP-1 and BMP-2 of the periodontal tissue at different time points. Results: The distances of orthodontic tooth movement were different significantly among 6 groups. HE results showed no significant changes in the periodontal tissue in control groups in different time; while in the experimental group, osteoblasts were regenerated in the tension side and osteoclasts regenerated in the compressive side of periodontal tissue. The expression of PLAP-1 on both sides reached the peak on the 3d in the experimental group, and higher on the tensional side than the compressive side, there existed significant difference among all the groups except for the 21d group. The expression of BMP-2 on both sides reached the peak on the 5d in the experimental group, and higher on the tensional side than the compressive side. Conclusion: The expression of PLAP-1 and BMP-2 reached the peak at different time points. References | Related Articles | Metrics

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Influence of Er:YAG Laser Treatment on Enamel Surface and Shear Bond Strength of Resin. SONG Dan-dan,FANG Hui-min,CAO Yang,YU Qing 2017, 33(1): 38-41.  DOI: 10.13701/j.cnki.kqyxyj.2017.01.009 Abstract ( 315 )   PDF (1855KB) ( 229 )   Objective: To investigate the influence of Er:YAG laser treatment on the characteristics of enamel surface and the bonding strength of resin. Methods: Fifty human premolars and molars without any caries and fillings were collected and eighty-four mesiodistal sections of the teeth were selected.The specimens were randomly divided into 7 groups(Group A-G) based on the different surface treatments (n=12).Two specimens in each group were randomly chosen and observed by scanning electron microscope (SEM). The other ten specimens in each group were bonded to the light-cured composite resin and the shear bond strength (SBS) were tested. Results: The highest SBS value of Group A was 20.51±3.33Mpa.The values of Group B,C and D were lower than that of Group A.However,the difference between these four groups was not statistically significant. The values of Group E,F and G were lower than those of other four groups.The differences between Group F and G and the other five groups were statistically significant. There was no significant difference between Group E and Group B,C and D. The SEM results showed that the surface roughness of enamel increased with the enhancement of laser energy.When the specimens were etched by acid after laser treatment process, the structure of enamel surface became uniform without smear layer and the structure of the enamel column was clearly visible. Conclusion: The Er:YAG erosion of enamel surface could not achieve a similar result as acid etching. The enamel surface treated by laser combined with etching could achieve similar effect with acid etching. The SBS results were increased with the increasing of laser energy. References | Related Articles | Metrics

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Three Dimensional Analysis of Passive Double Colpus of Self-ligating System--the Mechanical Property of Rotation. WU Xue, HE Song, YANG Qin-pei, WEI Dai-lun, HE Han, HUANG Yue 2017, 33(1): 42-46.  DOI: 10.13701/j.cnki.kqyxyj.2017.01.010 Abstract ( 204 )   PDF (1934KB) ( 213 )   Objective: To discover the mechanical property and the change rule about the tooth rotation of the passive double colpus of self-ligating system by using 3-D finite element analysis. Method: Damon Q bracket was selected as the objective. 3-D finite element models of the Damon Q and the wire with different size were established. Researchers assembled the models, did the mesh division, set up parameter and loaded power. After that, data were analyzed and graphs were drawn. Result: When assembled a single wire, the torsional torque value increased with the size of wire. In the double wire group, the torsional torque value increased with the size of assistant wire under the same main arch wire; when the assistant wire was immutable, there showed a positive correlation between the torsional torque value and the size of main arch wire. When using the same size of wire in the main colpus, torsional torque value of the single wire group was much less than the double wire group. Conclusion: The torsional property of the double wire group was much higher than the single wire group. Logical use of the assistant-horizontal colpus would be good for correcting the rotated teeth. References | Related Articles | Metrics

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Effects of Prednisone on Clinical Outcome and Immune Parameters in the Treatment of Refractory Recurrent Aphthous Ulcer RUAN Huan-huan, WANG Wen-mei, WANG Xiang, DUAN Ning, JIANG Hong-liu, BAI Yang, LI Jing-jing, QIAN Ya - jie, ZHOU Qian 2017, 33(1): 47-50.  DOI: 10.13701/j.cnki.kqyxyj.2017.01.011 Abstract ( 204 )   PDF (803KB) ( 221 )   Objective: To investigate the effects of low-dose and short-course oral prednisone on clinical outcome and immune parameters adjustment in the treatment of refractory recurrent aphthous ulcer (refractory RAU). Methods: Thirty-seven cases of patients with refractory RAU were administered with low-dose oral prednisone for one month. Ten mg/d prednisone for 20 days was then reduced to 7.5 mg/d for 5 days, and subsequently reduced to 5 mg/d for the last 5 days. Before and after treatment, blood routine, liver and kidney function, humoral and cellular immunity-related parameters in peripheral blood were tested. The clinical outcome and adverse reactions were evaluated after the treatment and two months later. Immune parameters change was observed after treatment. Results: The total efficiency was 100% after the treatment, and 91.4% at two months after the treatment. The levels of immunoglobulins and complements (IgG, IgA, IgM, IgE and C4) in peripheral blood significantly altered after the treatment (P<0.05). The percentages of immune cells (B and T lymphocytes and NK cells) in peripheral blood did not significantly change after the treatment. Conclusion: Low-dose and short-course oral prednisone therapy is effective in the treatment of refractory RAU with on adverse reaction, through prolonging intermission, reducing numbers and sizes of ulcers and decreasing pain index. The adjustment of humoral immunity could be one of the ways to treat refractory RAU. References | Related Articles | Metrics

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Effects of Different Concentrations of Phosphoric Acid Etching on the Micro-Tensile Bond Strength of Fluorosed Enamel LV Lin-hu,ZHOU Hui,LI jia-ling,GUO Ling 2017, 33(1): 51-54.  DOI: 10.13701/j.cnki.kqyxyj.2017.01.012 Abstract ( 210 )   PDF (1599KB) ( 255 )   Objective: To evaluate the effect of different concentrations of phosphoric acid etching on the micro-tensile bonding strength of fluorosed enamel. Methods:The specimens were divided into four groups: thirty health teeth in the control group and ninty fluorosed teeth in three experimental groups. The three experimental groups were divided mild group, moderated fluorosis group and severe fluorosis group by TFI standard. Each group was divided into three sub-groups by different concentrations of phosphoric acid treatment. The micro-tensile bonding strength (MTBS) was tested and the enamel surfaces were observed by SEM. Results:The MTBS in fluorosis group was lower than that in the control group (P<0.05). The bonding strength was significantly different when enamels were treated with different concentrations of phosphoric acid (P<0.05). For fluorosis teeth, the MTBS was the highest when treated with 40% acid. However, for the normal teeth, the MTBS was the highest when treated with 45% acid. Conclusion: The MTBS in the fluorosed group was lower than that of the control group. The bonding strength of dental fluorosis can be altered by etching with different concentrations of acid, but excessively high concentration of acid can conversely lead to an apparent decline of bonding strength. References | Related Articles | Metrics

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Characteristics of Temporomandibular Joint by Cone-beam Computed Tomography in Patients with Skeletal Class Ⅲ Malocclusion in Mixed Dentition. ZOU Shao-dan, CHEN Ming-zhu, YIN Kang 2017, 33(1): 55-59.  DOI: 10.13701/j.cnki.kqyxyj.2017.01.013 Abstract ( 232 )   PDF (1069KB) ( 354 )   Objective: To investigate the features of temporomandibular joint by cone-beam computed tomography (CBCT) in patients with skeletal class Ⅲ malocclusion in mixed dentition, and to explore the mechanism of the growth and remodeling of the temporomandibular joint. Methods: Twenty patients with skeletal class Ⅲ malocclusion and twenty patients with skeletal classⅠmalocclusion in mixed dentition were selected from the Department of Orthodontics, Stomatological Hospital affiliated to Kunming Medical University. NNT viewer 5.3 software was utilized to measure the relevant parameters from the CBCT scanning data. The acquired data were then analyzed. Results: Compared with the patients with skeletal classⅠmalocclusion in mixed dentition, the patients with skeletal class Ⅲ malocclusion in mixed dentition showed characteristics as follow: (1) in sagittal plane, bilateral anterior and superior spaces between the condyle and the fossa were smaller, and the gradient of the articular tublecle were smaller; (2) in coronal plane bilateral medial and superior spaces between the condyle and the fossa were smaller, and the condylar angle were smaller in the right side; (3) in the transverse cross section plane the right condylar anteroposterior diameters were smaller. Conclusion: (1) The temporomandibular joint of patients with skeletal class Ⅲ malocclusion in mixed dentition is not fully developed, and condyle, condylar fossa depth, gradient of articular tubercle, coronal medial and superior joint space are smaller. (2) The condyle usually locates anteriorly near to the roof of the fossa in patients with skeletal class Ⅲ malocclusion in mixed dentition. (3) The image characteristics of the temporomandibular joint in patients with skeletal class III malocclusion are adapted to their biological functions. References | Related Articles | Metrics

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Preparation and Characterization of Composite Thermo-sensitive Gel for Alveolar Ridge Preservation. MU Ting-ting, YANG Tao, ZANG Cheng-cheng, WANG Jian, SUI Lei 2017, 33(1): 60-64.  DOI: 10.13701/j.cnki.kqyxyj.2017.01.014 Abstract ( 262 )   PDF (2615KB) ( 325 )   Objective: To develop multi-walled carbon nanotube/nano-hydroxyapatite/chitosan(CS)/β-glycerophosphate(GP) injectable thermo-sensitive gels and to explore its feasibility as alveolar ridge preservation material. Methods: Wet-chemical in-situ precipitation route was used to obtain CNT/HA inorganic composites (HAC), which were dispersed in chitosan solution to obtain multi-walled carbon nanotube/nano-hydroxyapatite/chitosan thermo-sensitive gels. Gelation time, hole size, the porosity, mechanical strength and the percentage weight loss were selected as indicators to optimize the matching. The microstructure and physicochemical properties of the thermo-sensitive gels were characterized. Results: The results showed that the gel-forming property, including certain porosity (84%) and improved mechanical properties (0.441MPa), could be well tuned by controlling the amount of HAC (10 mg/mL) composite incorporated. In addition, certain amounts of HAC made the degradation rate controllable and shorten the clinical operation time to 12 min. Conclusion: The HAC loaded CS/GP composite scaffolds developed in this study exhibited good formability and mechanical properties and it might be a promising selection for bone tissue engineering. References | Related Articles | Metrics

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Comparison of Root Canal Morphology of Mandibular Incisors with Cone-beam Computed Tomography and RVG. JI Yan, WANG Tie-mei, LIU Shu, WEN Shan-hui, LIN Zi-tong 2017, 33(1): 65-69.  DOI: 10.13701/j.cnki.kqyxyj.2017.01.015 Abstract ( 254 )   PDF (1209KB) ( 328 )   Objective: To compare the differences between Cone-beam computed tomography (CBCT) and Radio visio graphy (RVG) technique in evaluating root canal morphology of mandibular incisors. Methods: One hundred and one extracted mandibular incisors were used in this study. Labial-lingual, mesial-distal RVG projection and CBCT scan at the HZ DS mode were done. The number of root canals, the Vertucci's classification, the calcification of root canal and the position of apex were evaluated. A mathematical model was established to calculate the angle of x-ray tube inclination. Results: Thirty-six teeth were found to have a second root canal in mesial-distal RVG images, and 30 incisors were considered to have two root canals in CBCT images. There were significant differences between CBCT and RVG as to the number of root canals and Vertucci's classification(P<0.05), but insignificant differences with regard to calcification of root canal and the position of apex. In the 30 incisors with two root canals, when the distance between the labial and lingual root canal (LaL) ranged between 0 and 1.5mm, 85.7% was Vertucci type III; when LaL ranged between 1.5 and 2mm, 66.7% were Vertucci type IV and V. If the distance pre- 基金项目 江苏省自然科学基金(编号:BK20150089,BK20141083) 南京市医学科技发展项目(编号:ZKX14049,YKK15116) 南京市卫生青年人才(编号:QRX11264) 作者简介 计艳(1982~ ),女,江苏溧阳人,主治医师,硕士,主要从事口腔疾病的预防工作。 *通讯作者 林梓桐,E-mail:linzitong710@163.com sent on the RVG images was set to 1mm, the projecting angle should be from 26.6° to 45.0°for the teeth with LaL ranged between 1 and 2mm, and from 45.0° to 84.3°with LaL ranged between 0.1 and 1mm. Conclusion: There were significant differences between CBCT and RVG for evaluation of the number of root canals and Vertucci's classification but insignificant differences for evaluation of calcification of root canal and the position of apex. It was more practical to do mesial-distal projection mandibular incisors with LaL ranged between 1 and 2mm. References | Related Articles | Metrics

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Anatomic Analysis of Root Canals of Chinese Mandibular Incisors by Micro-computed Tomography. BAI Yu-hao, TANG Lu, MENG Xian-jie, ZHAO Ying 2017, 33(1): 70-73.  DOI: 10.13701/j.cnki.kqyxyj.2017.01.016 Abstract ( 212 )   PDF (1183KB) ( 297 )   Objective: To investigate root canal morphology of Chinese mandibular incisors by micro-CT. Methods: One hundred and eight mandibular incisors were scanned by micro-CT and root canals were visualized by three-dimensional reconstruction. The morphology of the main root canal was classified, and the location and incidence of the second canal were recorded. Results: The most prevalent canal types were Vertucci type Ⅰ and type Ⅲ. The incidence rates were 78.70% and 14.81%, respectively, and the incidence of branch root canals was 24.07%. The second canal diverged 6.07±3.42mm apical to the cementoenamel junction. Conclusion: The root canal system of mandibular incisors has complex anatomical morphology. It is crucial to get familiar with the main root canal and branch root canal in order to improve the success rate of root canal treatment. References | Related Articles | Metrics

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Effects of Different Self Etching Adhesives and Resins on Microleakage of Class V Restorations. WANG Xin-ying, WAN Na, YAN Lei, YIN Yan-jiao, CAO Rong-rong, XIONG Meng-lin, GAO Wen-hui, WU Pei-ling 2017, 33(1): 74-77.  DOI: 10.13701/j.cnki.kqyxyj.2017.01.017 Abstract ( 293 )   PDF (1023KB) ( 225 )   Objective: To compare the effects of three kinds of self-etching adhesives and three kinds of resins on the microleakage of Class V restorations. Methods: Box-shaped class V cavities (3mm×2mm×2mm) were prepared at the neck of buccal and lingual surfaces of 45 freshly extracted third molars. The teeth were divided into 9 groups randomly. There were 5 teeth in each group with 10 cavities. The cavities in each group were restored by different combinations of adhesives and resins. After restored in the constant temperature water of 37℃ for 24 hours, the specimens were soaked in 1% methylene blue solution at room temperature for 24 hours. The specimens were cut buccolingually into two halves with carborundum disc, and the microleakage degree was observed under the stereomicroscope. Results: When matched with S3 bond adhesive, the microleakage of the specimens with different resins was significantly different (P<0.05). When matched with Easy one adhesive and Xeno V adhesive, there was no significant difference in the groups restored by different resins. When restored by Z350 resin and Clearfil AP-X Composite resins, the microleakage was significantly different with different adhesives (P<0.05). When TPH resin was matched with different adhesives, there was no significant difference. Conclusion: The occurrence of microleakage was the result of the interaction between the adhesive and the resin. When Class V cavities were restored clinically, the compatibility of the adhesives and composite resins should be taken into consideration. References | Related Articles | Metrics

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Short-Term Clinical Outcomes of Immediate Implantation versus Delayed Implantation after Socket Preservation in Maxillary Molar Area for Patients with Severe Chronic Periodontitis ZHOU Yong-min, XU Yan, WANG Xiao-jing, PANG Gang, YE Xing-ru, WANG Ying, HE Jia-ling 2017, 33(1): 78-82.  DOI: 10.13701/j.cnki.kqyxyj.2017.01.018 Abstract ( 274 )   PDF (1515KB) ( 465 )   Objective: To compare the short-term clinical outcomesof immediate implantationversus delayed implantationin preserved sockets of the maxillary molar areaafter systematic periodontaltreatment in patients with severe chronic periodontitis. Methods: Thirtypatients with severe chronic periodontitis and partially edentulous in the maxillary molar area were screened outfrom January 2013 to 2015 in the Department of Periodontology,Stomatologic Hospital & College, Anhui Medical University. After the control of periodontal infection, a total of 49 implants were implanted, including 23 immediate implantations and 26 delayed implantations. Implant supported dentures were made after 3-6 months. All patients were followed up for 6 months after loading. The implant failure and peri-implant tissue conditions were recorded. Results: Two implants failed in the immediate implantation group and one implant failed in the delayed implantation group. The survival rate was 91.30% and 96.15%, respectively. At the delivery of definitive crowns and 6 months after loading, all implants received periodontal examination and there was no statistically significant difference, including probe depth (PD), blooding index (BI), and blooding of probe (BOP). During the observation time, the definitive crowns and periodontal tissue of all successful implants were in good function. Conclusion: After comprehensive periodontal treatment andwell-control,the clinical outcome appears to be similar for immediate implantation and delayed implantation in the maxillary molar area for patients with severe chronicperiodontitis. References | Related Articles | Metrics

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Application of Molar Uprightor in the Treatment of Mesially Impacted Mandibular Second Molars. BEI Min, LI Huang, JI Tong, YAN Xiang 2017, 33(1): 83-85.  DOI: 10.13701/j.cnki.kqyxyj.2017.01.019 Abstract ( 308 )   PDF (1715KB) ( 308 )   Objective: To design a new type of appliance to upright the impacted mandibular second molars and observe the clinical effects. Methods: The looped molar retractor (LMR) had three components: bands, lingual arch, and loop with silver solding spurs and ligature regions. LMR was fabricated and used in the treatment of 5 cases with bilateral impacted mandibular second molar and 2 cases with unilateral impacted mandibular second molars. The clinical effects were observed and evaluated. Results: All the impacted second molars were up-righted successfully in short time. The average period of treatment was 4 months. The loss of anchorage was not observed. Conclusion: LMR is an ideal tool to up-right the impacted inclined second molar. References | Related Articles | Metrics

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Correlation Study on the Influence of Resveratrol on the Demineralized of Dentin Matrix. ZHAO Zhi-xiang, LIU Lu-bin, YUAN Xue-ming 2017, 33(1): 86-89.  DOI: 10.13701/j.cnki.kqyxyj.2017.01.020 Abstract ( 240 )   PDF (956KB) ( 191 )   Objective: To discuss the effects of resveratrol on matrix metalloproteinase-2 (mmp-2) activity and demineralization resistance and to provide experimental evidence for the clinical application of resveratrol. Methods: The concentration gradients of resveratrol were 12.5 μmol/L, 25 μmol/L, 50 μmol/L, 100 μmol/L, 200 μmol/L, and 400 μmol/L in the experimental group. 0.2% chlorhexidine was selected as the positive control group and deionized water as the negative control group. 10 μL of each group was mixed with 30 μL extracted odontogenic mmp-2 and incubated for 30 min. Metalloproteinase-2 activity was quantitatively detected with body fluid matrix metalloproteinase-2 activity assay after 20 min, and each group was repeated five times. After going through the pH cycle, electron microscopy and laser scanning confocal 3D image were used to observe dentin demineralization depth. Results: Resveratrol with the concentration above 50 μmol/L showed significant inhibitory effect. And metalloproteinase-2 activity inhibition rate in groups with the concentration of 100 μmol/L, 200 μmol/L, and 400 μmol/L showed no significant difference compared to the positive group. Confocal electron microscopy 3D image displayed that Res dyeing depth in the 100 μmol/L group was significantly lower than that in the negative control group. And statistical analysis showed the same results (P<0.05). But there was no significant difference between 100 μmol/L group and the positive control group. Conclusion: Resveratrol can inhibit the activity of matrix metalloproteinase-2 and dentin demineralization. References | Related Articles | Metrics

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Clinical Observation and Experimental Study of Minqing Ao Dental Desensitizer Combined with Er:YAG Laser on the Treatment of Dentine Hypersensitivity in Teenagers. LIU Zi-han, ZHOU Shu, ZHENG Hong, TANG Gen-xiong 2017, 33(1): 90-94.  DOI: 10.13701/j.cnki.kqyxyj.2017.01.021 Abstract ( 275 )   PDF (1498KB) ( 397 )   Objective: To study the clinical effect of Minqing Ao dental desensitizer combined with Er : YAG laser on the treatment of dentine hypersensitivity in teenagers. Methods: Seventy-eight cases (163 teeth) of dentine hypersensitivity in teenagers were randomly divided into the Minqing Ao group (n=54), the laser group (n=55) and the combined group (n=54). The Minqing Ao group was treated with Minqing Ao dental desensitizer alone, the laser group was treated with Er:YAG laser irradiation, and the combined group was treated with Er:YAG laser irradiation combined with the later Minqing Ao dental desensitizer. The visual analog scale (VAS) and total effective rate of the Minqing Ao group, the laser group and the combined group were compared before, immediately after, and 1 week, 1, 3, 6 months after treatment. Another 20 fresh teeth were selected and randomly divided into four groups. The dentin hypersensitivity model samples of four groups were treated by using normal saline, Minqing Ao dental desensitizer, Er:YAG laser, Minqing Ao dental desensitizer combined with Er:YAG laser respectively. Sample morphology of all 20 specimens was observed under scanning electron microscope. Results: The VAS of the combined group was significantly lower than that in the Minqing Ao group and in the laser group (P<0.05). Total effective rate of the combined group was significantly lower than that in the Minqing Ao group and the laser group immediately after and 1 week, 1, 3, 6 months after treatment (P<0.05). Total effective rate of the Minqing Ao 基金项目 江苏省卫生厅预防医学科研课题基金资助项目(编号:Y2013003) 作者简介 刘子晗(1987~ ),女,江苏连云港人,硕士,住院医师,主要从事口腔科的临床治疗工作。 *通讯作者 周淑,E-mail:13951878582@163.com group and the laser group immediate after and 1 week, 1 month, 3 months after treatment showed no statistical significance. Conclusion: Minqing Ao dental desensitizer combined with Er:YAG laser in the treatment of dentine hypersensitivity in teenagers has better clinical effects. References | Related Articles | Metrics

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Impact of Fluoride Foam on Periodontal Index and Enamel Demineralization for Patients with Lingual Orthodontic Treatment MENG Qiu-ju, WANG Lei-chang, DU Xi, HUANG Jian 2017, 33(1): 95-98.  DOI: 10.13701/j.cnki.kqyxyj.2017.01.022 Abstract ( 211 )   PDF (793KB) ( 351 )   Objective: To study the effect of fluoride foam on periodontal index and enamel demineralization for patients with lingual orthodontic treatment. Methods: Thirty patients (600 teeth) with lingual orthodontics from June 2013 to June 2014 were divided into control group (15 cases, 297 teeth) and observation group (15 cases, 293 teeth). The control group accepted routine oral hygiene methods, and the observation group was given 1.23% fluoride foam. After follow-up of 12 months, the enamel demineralization of dental distribution, EDI, PLI and BI were compared between two groups. Results: Enamel demineralization was mainly distributed in the maxillary lateral incisors, maxillary incisors and mandibular premolar. The enamel demineralization rate of observation group was 11.26%, which was significantly lower than that the control group (17.51%, P<0.05). The EDI, PLI, and BI of observation group were significantly lower than those of control group (P<0.05). Conclusion: During lingual orthodontic treatment, the enamel demineralization rate was high. Fluoride foam helps to reduce the enamel demineralization and reduce the periodontal index. References | Related Articles | Metrics

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Effect of Lemon Essential Oil on Periodontal Pathogens LI Tang-ping, BIAN Ke-yin, ZHANG Xiang-yu 2017, 33(1): 99-101.  DOI: 10.13701/j.cnki.kqyxyj.2017.01.023 Abstract ( 205 )   PDF (784KB) ( 271 )   Objective: To investigate effects of lemon essential oil (LEO) on the growth and adherence of periodontal pathogens. Methods: Microplate dilution assays were performed to determine the antibacterial effect of LEO on Prophyromonas gingivalis (Pg), Fusobacterium nucleatum (Fn), A.actinomycetemcomitan (Aa), and P.intermedius (Pi). MTT method was employed to study the cytotoxic activity of LEO on human umbilical vein endothelial cells (HUVECs). Results: The LEO exhibited moderate antibacterial activity on Pg and Pi (Minimum inhibitory concentration: MIC =9mg/mL) and strong antibacterial activity on Fn and Aa (MIC= 4.5mg/mL). The minimal bactericidal concentration (MBC) was 9.0mg/mL (Fn and Aa). LEO showed no killing effect on Pg and Pi. The LEO’s concentration (<1/200 MIC) revealed no toxicity on HUVECs. Conclusion: LEO has a great potential to be used to treat periodontitis. References | Related Articles | Metrics

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Efficacy of Er:YAG Laser Treatments of Root Canal Walls on the Pull-out Bond Strength of Fiber Posts LI Jin-hong, JIN Dong-mei, WANG Su 2017, 33(1): 102-105.  DOI: 10.13701/j.cnki.kqyxyj.2017.01.024 Abstract ( 209 )   PDF (1041KB) ( 239 )   Objective: To evaluate the effects of Er:YAG laser irradiation under different power settings on the micro tensile bond strength (μTBS) of fiber-reinforced composite posts. Methods: Root canals of 60 single-rooted human teeth were filled and post spaces were prepared. Specimens were divided randomly into five groups, each consisting of 12 specimens as follows: control group, 3W-50μs Er:YAG laser, 3W-100μs Er:YAG laser, 4.5W-50μs Er:YAG laser, and 4.5W-100μs Er:YAG laser. After the root canal procedures, fiber posts were cemented to the root canal. Micro-tensile bond strength tests were performed using a universal testing machine at a crosshead speed of 1 mm/min. The data were analyzed using a two-way ANOVA test (α=0.05). Results: Irradiation by the 3W-100μs Er:YAG laser positively affected the micro-tensile bond strength (5.55±0.97MPa). The bond strength was significantly higher than that of control group (4.06±1.22 MPa, P＜0.05). Conclusion: Er:YAG laser may alter the dentin bond durability. References | Related Articles | Metrics

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Application of Platelet Rich-fibrin with GBR in Anterior Immediate Implantation. SUN Xiao-lin, ZHAI Jing-jie, SUN Yue, LIU Zhen-zhen, ZHOU Yan-min 2017, 33(1): 106-107.  DOI: 10.13701/j.cnki.kqyxyj.2017.01.025 Abstract ( 419 )   PDF (1104KB) ( 367 )   Objective: To investigate the clinical effectiveness of platelet rich-fibrin (PRF) on immediate implantation in the fresh extraction sites of anterior teeth. Methods: After anterior tooth was extracted, one implant was placed into the fresh extraction site. Guided bone regeneration (GBR) was performed and PRF was placed in surgical wound. Results: The regeneration of periodontal tissue was visible after clinical examination. The radiograph demonstrated that the space around the implant was filled with a dense bone-like tissue. Conclusion: PRF could serve as a viable material for tissue regeneration around immediately placed implant in the anterior region. References | Related Articles | Metrics

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Research Progress on Dental Pulp Regeneration. LIU Jin-feng, NIU Xue-wei, CHAO Bo, ZHANG Zhi-min 2017, 33(1): 108-111.  DOI: 10.13701/j.cnki.kqyxyj.2017.01.026 Abstract ( 440 )   PDF (817KB) ( 704 )   Although current root canal therapy offers a high success rate for many teeth with pulp diseases, there are still many post-treatment complications. Due to the application of tissue engineering technology in dentistry, it is possible that the dental pulp dentin complex can be regenerated. In recent years, there are a lot of researches on dental pulp regeneration in our country and abroad. This review presents recent progresses in dental pulp reconstruction. References | Related Articles | Metrics

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Progress of Prenatal Diagnosis of Cleft Lip and Palate. LIU Li-ping, DU Yang-ge, YANG Xiao-hong, QIN Chuan-qi 2017, 33(1): 112-114.  DOI: 10.13701/j.cnki.kqyxyj.2017.01.027 Abstract ( 323 )   PDF (791KB) ( 452 )   Cleft lip and/or palate (CL/P) is the most common orofacial malformation. Half of cases are Cleft lip and palate. CL/P may occur as an isolated finding or may be found in association with other congenital malformations. Major medical and psychological problems may ensue following this diagnosis for both the child and its family. It is important that they are diagnosed as early as possible during the antenatal period to allow adequate counseling of the parents and to provide neonatal care. Prenatal ultrasonographic screening is found to be an accurate tool for the prenatal diagnosis of CL/P in high risk groups, particularly when it is associated with other structural malformations. Magnetic resonance imaging may be ancillary to ultrasound in prenatal investigation of a fetus with cleft lip, allowing a better staging of the lesion by demonstrating the degree of involvement of the palate. Prenatal genetic examination can determine whether the fetus associated with CL/P cause chromosomal disease research. References | Related Articles | Metrics