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20 April 2015, Volume 24 Issue 2 Previous Issue    Next Issue

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Basic Study

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In vitro study of electrospun polycaprolactone/chitosan nano fiber membrane guided bone regeneration HE Ying,LIU Xin,TANG Xu-yan 2015, 24 (2):  129-134.  Abstract ( 247 )   HTML ( 2 )   PDF (2299KB) ( 445 )   PURPOSE: To explore the effect of electrospining chitosan/polycaprolactone nano fiber membrane on regeneration of bone defects in vitro. METHODS: Chitosan/ polycaprolactone nanofiber membrane was prepared by electrospinning technique. According to alkaline phosphatase activity and Western blot results, the ability of osteogenic differentiation of cells by fiber membrane as carrier was evaluated. The data was analyzed statistically with SPSS17.0 software package. RESULTS: The osteogenic differentiation capacity of electrospining chitosan/polycaprolactone nano fiber membrane was significantly higher than the control (without materials), and the difference was significant (P<0.05). CONCLUSIONS: Electrospinning chitosan/polycaprolactone nano fiber membrane can promote osteogenic differentiation of cells in vitro, which provides a scientific basis for clinical regeneration of bone defects. References | Related Articles | Metrics

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Immortalization of human dental pulp stem cells caused by transferring hTERT gene GAO Li,WANG Yu-xia,JIANG Wen-xin,HE Zhi-yan,ZHU Cai-lian,MA Rui 2015, 24 (2):  135-140.  Abstract ( 299 )   HTML ( 2 )   PDF (1786KB) ( 372 )   PURPOSE: To establish an immortalized human dental pulp stem cell line used for basic and clinical research of oral science. METHODS: Human telomerase reverse transcriptase (hTERT) cDNA was transferred into human dental pulp stem cells (hDPSCs) by lentivirus. The resultant stable clones reproduced successively and the expression of hTERT was identified. RESULTS: The hTERT gene was transferred into human dental pulp stem cells successfully. The transformed cells expressed telomerase activity and divided vigorously. p35 had been obtained so far. CONCLUSIONS: The hDPSCs can be immortalized by transferring exogenous hTERT gene to constitute telomerase activity. References | Related Articles | Metrics

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The effect of fluoride on adhesion of Streptococcus mutans and Streptococcus sanguis on the dental pure titanium surface WANG Jue,QIAO Guang-yan,SHEN Qing-ping,GU Kai-kai 2015, 24 (2):  141-146.  Abstract ( 200 )   HTML ( 0 )   PDF (1887KB) ( 414 )   PURPOSE: This study was to investigate the effect of fluoride on adhesion of Streptococcus mutans and Streptococcus sanguis on the dental pure titanium surface. METHODS: The adhesion of Streptococcus mutans and Streptococcus sanguis on the dental pure titanium surface were examined by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay after soaked in artificial saliva containing different concentrations of sodium fluoride for 24 h. Then the surface roughness and surface morphology of the pure titanium were analyzed by atomic force microscope after bacterial adhesion experiments. The data was statistically analyzed by analysis of variance(ANOVA) with SPSS11.0 software package. RESULTS: After soaked in artificial saliva containing different concentrations of sodium fluoride for 24 h, the sequence of OD values showed the adhesion of Streptococcus mutans and Streptococcus sanguis on dental pure titanium surface was 0 g/L < 0.5 g/L < 1.0g/L < 2.0 g/L (P<0.05). In addition, the sequence of Ra values showed the surface roughness of pure titanium after bacterial adhesion experiments was 0 g/L < 0.5 g/L < 1.0g/L < 2.0 g/L (P<0.05). And the surface morphology of pure titanium was consistent with the changes of OD value and Ra value. CONCLUSIONS: The results of adhesion of Streptococcus mutans and Streptococcus sanguis, surface roughness and surface morphology reveal that fluoride aggravates the corrosion of pure titanium, increases the surface roughness, and thus promots the adhesion of Streptococcus mutans and Streptococcus sanguis on the titanium surface. References | Related Articles | Metrics

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Preparation and examination of BMP-2 loaded chitosan nanospheres in vitro LIU Feng,SUN Jian,LI Ya-li,CHEN Li-qiang,XIE Jing-sen,ZANG Xiao-long 2015, 24 (2):  147-150.  Abstract ( 234 )   HTML ( 2 )   PDF (983KB) ( 430 )   PURPOSE: To prepare chitosan nanospheres for loading of BMP-2 and to evaluate its size, zeta potential, appearance, degradation and release characteristic in vitro, and then to investigate its feasibility as a carrier for sustained release of BMP-2. METHODS: The BMP-2 loaded chitosan nanospheres were prepared using ionic crosslinking method with tripolyphosphate (TPP) and chitosan. Transmission electron microscope was used to evaluate the morphological properties, and laser particle size analyzer was used to analyze particle size, Zeta potential and distribution. Lysozyme degradation experiment was performed to assess the biodegradation behavior. ELISA assay was used to determine the loading efficiency, encapsulation efficiency and in vitro drug release kinetics. The data was analyzed by SPSS 19.0 software package. RESULTS: The BMP-2 loaded chitosan nanospheres were spherical in shape, smooth on surface and uniform dispersion without aggregation. The mean diameter was 150.85 nm. The dispersion index was 0.37, and zeta potential was +35.42 mV. The average loading efficiency and encapsulation efficiency were (56.83±2.26)% and (68.24±3.83)%, respectively. Release experiment in vitro showed that the releasing property of BMP-2 loaded chitosan nanospheres was consistent with two-phase kinetic regulation and BMP-2 was controlled to release from the chitosan nanospheres over 30 days. CONCLUSIONS: The BMP-2 loaded chitosan nanospheres prepared by ionic crosslinking method are successfully prepared which show a good controlled release property. It provides the basis for further application in bone tissue engineering. References | Related Articles | Metrics

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Effect of IL-1β on inflammatory factors synthesis of human gingival fibroblasts attached to different titaniums SUN Zhi-xin,ZHANG Yun-tao 2015, 24 (2):  151-156.  Abstract ( 268 )   HTML ( 2 )   PDF (1410KB) ( 256 )   PURPOSE: To evaluate the effects of IL-1β on inflammatory factors synthesis of human gingival fibroblasts on different surfaces of titaniums in vitro. METHODS: Human gingival fibroblasts were cultured on 3 different kinds of titaniums. The cells were stimulated with IL-1β, and the IL-6 and IL-8 production was detected by polymerase chain reaction (PCR) after 3, 6 and 24 h. The date was statistically analyzed with SPSS13.0 software package. RESULTS: A significant increase of the expression of gingival fibroblasts to inflammatory factors (IL-6, IL-8) after IL-1β was noted; PCR results of the production of inflammatory factors in gingival fibroblasts with the intervention of IL-1β showed that the production of inflammatory factors (IL-6, IL-8) on titanium and titanium alloy were less than that on the titanium nitride. CONCLUSIONS: IL-1β can stimulate high expression of inflammatory factors; The production of IL-6 and IL-8 on titanium and titanium alloy are less, suggesting that implant made of titanium and titanium alloy can reduce the incidence of peri-implant inflammation, and improve the successful rate of implantation. References | Related Articles | Metrics

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Finite element analysis of the angulation designment of implant planning in the anterior maxilla HAN Li-Hui,QIU Xiao-Xia,XING Xu-Na,CAI Liu-Yi 2015, 24 (2):  157-163.  Abstract ( 226 )   HTML ( 1 )   PDF (1969KB) ( 297 )   PURPOSE: To provide theoretical reference for maxillary anterior restoration designment in clinics by observing the masticatory stress distribution of the implant-bone interface and the displacement of implant. METHODS: This study built simplified 3 dimensional finite models with different angles, which included partial implant (4.3 mm×11.5 mm), abutment and all ceramic crown (Zirconia) and combined with angle of implant A between the long axis of ideal implant and factual implant (0°, 5°, 10°, 15°, 20°, 25°), as well as angle of abutment B between the long axis of abutment and implant (0°, 5°,10°,15°,20°,25°). A force load of 178 N was applied 2 mm below the incisal edge on the palatal surface of the crown, with an approximately 130°angle to the long axis of the crown. The displacement of implant maximum principal stress value and distribution of the implant-bone interface were determined by using Ansys 13.0 software. RESULTS: Sixteen 3-dimensional models of different implant restoration plan of implant dentures of maxillary incisor were built. When the angle of abutment was increasing with the same labial inclination of implant, the objective functions were enhanced. When the labial inclination of implant was increasing with the same angle of abutment, the objective functions were also improved. With the change of labial inclination of implant and angled abutment, the labial inclination of implant concentrated more than the angle of abutment on the objective functions. When the angle of abutment was between 0 degree and 20 degree, the amplitude of all the objective functions were gentle, while the labial inclination of implant and amplitude of all the objective functions were increased when the angle of abutment increased to 25 degree. CONCLUSIONS: A positive correlation is found between the value of stress of the bone around the implant, and the displacement of implant and the labial inclination of the implant and the angle of abutment. It is necessary to decrease the labial inclination of the implant and the angle of abutment, especially strictly control the labial inclination of the implant. Taking the stress and displacement into consideration, both of two angles ranging from 0 degree to 20 degree are the best optimal choice for the anterior implants. When both of two angles increase to much greater than 20 degree, the value of stress increase remarkably, which will decrease the chance of successful implant. References | Related Articles | Metrics

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Biomechanical analysis on healing process of sagittal fracture of the mandibular condyle after rigid fixation JING Jie,QU Ai-li,DING Xiao-mei,HEI Yu-na 2015, 24 (2):  164-169.  Abstract ( 302 )   HTML ( 2 )   PDF (2275KB) ( 361 )   PURPOSE: To analyze the biomechanical healing process on rigid fixation of sagittal fracture of the mandibular condyle (SFMC), and to provide guidelines for surgical treatment. METHODS: Three-dimensional finite element model (3D-FEAM) of mandible and condyle was established. The right condyle was simulated as SFMC with 0.1 mm space across the condyle lengthways. The 3D-FEAM of rigid fixation was established. The biomechanical factors such as stress distribution of condylar surface, displacement around fracture, stress on the plate and stress shielding were calculated during 0, 4, 8 and 12-week after rigid fixation. RESULTS: The maximum equivalent stress of normal condyle was located at the area of middle 1/3 of condylar neck. The maximum equivalent stress at 0-week after fixation was 23 times than that on normal condyle. They were located at the condylar stump and the plate near inferior punctual areas of fracture line. There were little stress on the other areas. The maximum equivalent stress at 4, 8 and 12-week was approximately 6 times than that on normal condyle. They were located at the areas same as the area at 0-week. There were little stress on the other areas at the condyle. The maximum total displacement and maximum total corner were increased 0.57~0.75 mm and 0.01~0.09° respectively during healing process. The maximum equivalent stress at 0-week on the condylar trump was 5~6 times compared with that at 4, 8, and 12-week. The maximum equivalent stress, maximum total displacement and maximum total corner on the fractured fragment were not changed significantly during healing process. The maximum equivalent stress at 0-week on the plate was 7~9 times compared with that at 4, 8, 12-week. CONCLUSIONS: The stress of the condyle and stress shielding of the plate may be the reasons of absorbing and rebuilding on the condyle in healing process of SFMC. The biomechanical parameters increase obviously at 4-week after fixation. Elastic intermaxillary traction is necessary to decrease total displacement and total corner of the condyle, and liquid diet is necessary to decrease equivalent stress within 4 weeks. Rehabilitation training should be used to recover TMJ functions after 4 weeks because the condyle and mandible have the ability to carry out normal functions. References | Related Articles | Metrics

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The finite element analysis of stress distribution in different size of MO cavities restored with composite resin inlays ZHANG Long,LU Yi,YANG Bo-song,GUO Yan,LI Fang-ping 2015, 24 (2):  170-176.  Abstract ( 266 )   HTML ( 1 )   PDF (3379KB) ( 370 )   PURPOSE: To explore the effect of different depth and width of meiso-occlusal (Class Ⅱ) cavity type on the tooth tissue resistance stress after restoration with composite resin inlays. METHODS: The 3-D finite element model of mandibular first molar with meiso-occlusal (ClassⅡ) cavity restored with composite resin inlay was established by using CBCT scanning and reverse engineering software Mimics, Geomagic Studio, and finite element analysis software ANSYS. Comparative analysis of restoration with different depth and width meiso-occlusal (ClassⅡ) cavity under the same load of perpendicular and 45° deviation was explored, and finally the main stress and Von-mises stress changed as well as stress distribution were analyzed. RESULTS: The main stress was located in the gingival wall opposite to the inlay, while the major stress concentration area of the tooth was distributed near the canal at the bottom of the cavity. With the increase of the depth and width, the main stress and Von-mises stress distribution areas of tooth were getting larger. The Von-mises stress of tooth was influenced by the width variation of the cavity, while that depth change of cavity was affected by Von Mises stress of the inlay. CONCLUSIONS: With the increase of the depth and width of the cavity as well as lateral loading force, the peak stress of tooth with inlays increased and the distribution of stress concentration is modified after meiso-occlusal (ClassⅡ) cavity being inlayed with composite resin. References | Related Articles | Metrics

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Preliminary study of bonding strength between diatomite-based dental ceramic and veneering porcelains LU Xiao-li,GAO Mei-qin,CHENG Yu-ye,ZHANG Fei-min 2015, 24 (2):  177-181.  Abstract ( 252 )   HTML ( 1 )   PDF (1645KB) ( 274 )   PURPOSE: In order to choose the best veneering porcelain for diatomite-based dental ceramic substrate, the bonding strength between diatomite-based dental ceramics and veneering porcelains was measured, and the microstructure and elements distribution of interface were analyzed. METHODS: The coefficient of thermal expansion (CTE) of diatomite-based dental ceramics was detected by dilatometry. Three veneering porcelain materials were selected with the best CTE matching including alumina veneering porcelain (group A), titanium porcelain veneering porcelain (group B), and E-max veneering porcelain (group C). Shear bonding strength was detected. SEM and EDS were used to observe the interface microstructure and element distribution. Statistical analysis was performed using SPSS 17.0 software package. RESULTS: The CTE of diatomite-based dental ceramics at 25-500℃ was 8.85×10-6K-1. The diatomite-based substrate ceramics combined best with group C. Shear bonding strength between group A and C and group B and C both showed significant differences(P<0.05). SEM and EDS showed that the interface of group C sintered tightly and elements permeated on both sides of the interface. CONCLUSIONS: The diatomite-based substrate ceramics combines better with E-max porcelain veneer. References | Related Articles | Metrics

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Effects of morphology of the microgroove titanium surface on expression of vinculin in human gingival fibroblasts LAI Ying-zhen,CHEN Jiang,LIN Shan 2015, 24 (2):  182-187.  Abstract ( 216 )   HTML ( 0 )   PDF (2216KB) ( 366 )   PURPOSE: To investigate the effects of morphology of the microgroove surface on the expression of vinculin in human gingival fibroblasts, with the hope of providing basis for size selection of microgroove for transmucosal part of dental implants. METHODS: Microgroove titanium surfaces were fabricated by photolithography with parallel grooves: 15 μm, 30 μm or 60 μm in width and 5 μm or 10 μm in depth. The groups that used different microgroove surfaces were denoted as T15/5, T15/10, T30/5, T30/10, T60/5, and T60/10. Smooth titanium surfaces (T0) were used as controls. Surface topography was detected. HGFs were cultured on the microgroove surfaces. Morphology of vinculin was analyzed using CLSM. Expression level of vinculin was compared among different groups by real-time PCR and Western blotting. SPSS17.0 software package was used for statistical analysis. RESTULTS: Immunofluorescence staining revealed increase of green vinculin fluorescent spots as the increase of microgroove width, while T60 group had the highest mRNA and protein expression and T15 group had the lowest. Microgroove depth had no effect on the expression of vinculin under the same width. CONCLUSIONS: Morphology of microgroove surface has effect on the expression of vinculin, and the morphology of microgroove surface in T60 group is the best size for the transmucosal part in terms of expression of vinculin protein expression. References | Related Articles | Metrics

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Study on antimicrobial effect of the mixture of Chinese medicine-chitosan to Candida albicans and the possibility as denture adhesive LI Lv,MENG He,LI Jin-yuan,WU Wen-hui,LIANG Rui-ying 2015, 24 (2):  188-192.  Abstract ( 246 )   HTML ( 1 )   PDF (1099KB) ( 252 )   PURPOSE: To observe the antimicrobial effect and the tensile bond strength of water-soluble chitosan after adding different Chinese medicines to Candida albicans. METHODS: The extract of 6 kinds of Chinese medicine by decoction in different concentrations were mixed with chitosan, and the most effective mixture inhibiting Candida albicans and the minimal inhibitory concentration (MIC) were explored; Then the tensile bond strength of the mixture was tested and compared with Protefix denture adhesive. The data was analyzed with SPSS17.0 software package. RESULTS: The antibacterial effect of polyphylla-chitosan mixture was the best among the 6 kinds of Chinese medicine- chitosan mixture, and its MIC was 1.563 mg/mL. The tensile bond strength of polyphylla-chitosan mixture at 0 h and 12 h when immersed in artificial saliva were significantly larger than Protefix denture adhesive. The average value and the maximum value was significantly greater than the Protefix denture adhesive (P<0.05). CONCLUSIONS: Polyphylla-chitosan mixture has good antibacterial effect on Candida albicans and large tensile bond strength. References | Related Articles | Metrics

Clinical Study

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Expression of CXC chemokine ligand 16 and chemokine receptor 6 in periodontal tissues of patients with moderately severe periodontitis SUN Xiao-ju,HOU Jun-chi,XIE Hong,ZHANG Hui,DENG Wei,WANG Yun 2015, 24 (2):  193-198.  Abstract ( 311 )   HTML ( 0 )   PDF (1597KB) ( 242 )   PURPOSE: To investigate the expression and localization of CXCLl6 and its receptor CXCR6 in gingival tissues of patients with chronic periodontitis and analyze the roles in the occurrence and development of periodontitis. METHODS: Gingival tissues with moderately severe periodontitis were collected from 39 patients treated in People's Hospital of Liaoning Province. Forty persons with healthy gingiva were used as control. The age of the enrolled subjects ranged from 35 to 74 years old. Immunohistochemical technique was applied to detect the expression and localization of CXCLl6 and CXCR6 protein gingival tissues of all subjects. The data was analyzed with SPSS 15.0 software package. RESULTS: Compared with normal group, the expression of CXCLl6 and CXCR6 were significantly up-regulated in patients with periodontitis (P<0.05). There was a positive relationship between the protein expression of CXCLl6 and CXCR6 in gingival tissues of patients with periodontitis (r=0.580, P<0.05). CONCLUSIONS: CXCLl6 and CXCR6 may be involved in the development of chronic periodontitis. The expression of CXCLl6 and CXCR6 may work coordinately to promote the development of chronic periodontitis. References | Related Articles | Metrics

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The labial and palatal bone thickness in 67 young adults with normal occlusion at the maxillary anterior teeth measured by cone-beam computed tomography JIA Xiao-shi,ZHANG Qiu-xia,XU Meng-jie,WANG Meng,ZHANG Peng 2015, 24 (2):  199-205.  Abstract ( 550 )   HTML ( 0 )   PDF (1147KB) ( 324 )   PURPOSE: To investigate the labial and palatal bone thickness of the maxillary anterior teeth in normal young adults on different reference lines, in order to provide references for clinical treatment. METHODS: Sixty-seven eligible Han nationality young volunteers were scanned by cone-beam computed tomography (CBCT). The labial and palatal bone thickness and the labial bone morphology of the anterior teeth were measured after reconstruction. Paired-sample t test, independent- sample t test, one-way ANOVA and Chi-square test were performed using SPSS17.0 software package. RESULTS: ①The mean labial bone thicknesses at L1 of canines and L5 of all anterior teeth were more than 1.00 mm, while the thickness of the other labial measurement sites were less than 1.00 mm. The mean palatal bone thickness was more than 1.00 mm. ② The labial bone was thinner than the palatal bone (P<0.001). ③The labial bone was the thinnest at L3 and L4 of the anterior teeth（P<0.001). The thickness of palatal bone gradually increased from the L1 to L5(P<0.001). ④ The frequency of the labial bone thinner than 1.00 mm was less than 50% at L2 of canines and L5 of all anterior teeth; The frequency of the labial bone deficiency at L3 and L4 of lateral incisors and L4 of canines was more than 50% in males. ⑤The mean buccal bony curvature of canines was larger than that of incisors in males. The distance between root apex and the deepest point of buccal bony curvature was the largest in maxillary central incisors zone in males, while there was no significant difference in females. CONCLUSIONS: The alveolar bone thickness of the maxillary anterior teeth in normal young adults are quite thin or even deficient, and there is diversity of the thickness and morphology between labial and palatal bone. References | Related Articles | Metrics

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Analysis of the possible causes of endodontic treatment failure by inspection during apical microsurgery treatment QIAN Wen-hao,HONG Jin,XU Pei-cheng 2015, 24 (2):  206-209.  Abstract ( 597 )   HTML ( 2 )   PDF (1009KB) ( 472 )   PURPOSE: To analyze the possible causes of previous endodontic treatment failure by microscopic inspection during apical microsurgery. METHODS: Two hundred and eighty-nine teeth of previous endodontic treatment failure were collected from patients in Shanghai Xuhui District Dental Center, between January 2006 and January 2014. All surgical procedures were performed by using an operating microscope, and 238 roots were included in the study. The surface of the apical root to be resected or the resected root surface after methylene blue staining was examined during the surgical procedure and inspected with 26 magnification to determine the state of the previous endodontic treatment by using an operating microscope. Fisher's exact test was used to analyze the data with SPSS 19.0 software package. RESULTS: Among the 238 roots with periapical surgery, analysis of the reasons for previous endodontic treatment failure included leaky canal (29.41%), missing canal (15.55%), underfilling (15.55%), anatomical complexity (7.98%), overfilling (4.20%), apical fenestration (4.20%), iatrogenic problem (3.36%), apical calculus (2.52%), apical cracks (1.68%) and unknown reasons (15.55%). The frequency of possible failure causes and tooth position were closely correlated (P<0.001). CONCLUSIONS: Apical microsurgery can better inspect possible causes of previous endodontic treatment failure, in order to improve the success rate of endodontic treatment. References | Related Articles | Metrics

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The relationship between labial-lingual inclination and the thickness of the alveolar bone in the mandibular central incisors assessed with cone-beam computed tomography TIAN Yu-lou,ZHAO Zhen-jin,HAN Kun,LV Pin,CAO Yu-ming,SUN Hong-jing,YU Mo,YUE Yang 2015, 24 (2):  210-214.  Abstract ( 726 )   HTML ( 2 )   PDF (1181KB) ( 540 )   PURPOSE: To investigate the alveolar bone thickness of mandibular central incisors with different labial-lingual inclinations by cone-beam computed tomography (CBCT). METHODS: CBCT and lateral cephalometric images of 60 patients were chosen. The data was respectively classified into 3 groups by L1-MP: lingual inclination group (L1-MP<85.6°); normal group (L1-MP 85.6°-99.6°), and labial inclination group(L1-MP>99.6°). Three-dimensional reconstruction was made for CBCT, and the sagittal images of the largest alveolar bone area along the tooth axis were chosen. The central incisor roots were divided into 4 sections from cementoenamel junction to root apex, then the labial and lingual alveolar bone thickness were measured and added up to get total alveolar bone thickness, and the occurrence of fenestration and dehiscence were recorded. The data was analyzed with SPSS 17.0 software package. RESULTS: The alveolar bone thickness on lingual side and the total bone thickness were significantly different between every 2 sections of all the measured zone. The average values of bone thickness on labial side were thinner than that on lingual side in sections of middle 1/2, root apex 1/4 and root apex. The total bone and lingual bone were thinner in lingual inclination group than in labial inclination group at root apex, root apex 1/4 and middle 1/2. Labial and lingual inclination group were more likely to develop dehiscence (P<0.05). CONCLUSIONS: Lingual and total alveolar bone of central incisors become increasingly thinner from root apex area to cementoenamel junction. The total bone and lingual bone are thinner in lingual inclination group than in labial inclination group. Labial or lingual inclined incisors have higher incidence of dehiscence. References | Related Articles | Metrics

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Use of fiber-reinforced chemical curing resin to close the inter-proximate space of the posterior teeth GUO Feng-qin,DING Xiao-hong,LIU Qi-ling,GENG Qi 2015, 24 (2):  215-218.  Abstract ( 267 )   HTML ( 3 )   PDF (1116KB) ( 318 )   PURPOSE: To investigate the clinical efficacy of using fiber-reinforced chemical curing resin to close the inter-proximate space of the posterior teeth and block the food impaction. METHODS: One hundred and sixty-two patients with food impaction of posterior teeth were selected in this study. The total number of the food impaction was 170. They were divided into narrow-gap group and wide-gap group according to the damage of the inter-proximate space. Jingjin enamel adhesive reinforced polyethylene fiber ribbon was used in both group to close the inter-proximate space. The patients were reviewed at 6-month and 1-year. After the second follow-up examination, 161 restorations of 154 patients were included in this study. The differences between the 2 groups were analyzed by Chi-square test with SPSS 13.0 software package. RESULTS: Statistical differences were found in the retention rate of the restorations at 6-month between the 2 groups (P<0.05). The retention rate in the narrow-gap group was significantly lower than that in the wide-gap group. However, there was no significant difference between the 2 groups at 1-year. There was no significant difference in integrality between the 2 groups at 6-month and 1-year. CONCLUSIONS: The use of fiber-rein forced chemical curing resin to close the inter-proximate space of the posterior teeth and block the food impaction is more suitable for patients with clinical crown elongation, gingival recession, alveolar bone loss and the tissue damages in the inter-proximate space, which will cause food impaction. References | Related Articles | Metrics

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Analysis of the outcomes of squamous cell carcinoma of maxillary sinus with 3 different comprehensive treatments PENG Hui,YE Mao-chang,WANG Lai-ping,LI Rong-xin,ZHOU Yu,WANG Yi,ZHU Wei-zheng 2015, 24 (2):  219-223.  Abstract ( 642 )   HTML ( 0 )   PDF (942KB) ( 299 )   PURPOSE: To study the medium or long-term survival rates of different methods used in the treatment of advanced squamous cell carcinoma of the maxillary sinus (SCMS). METHODS: Patients were treated by one of the following methods: 231 patients were treated with induction chemotherapy, followed by radical resection and radiotherapy (CSR); 128 patients were treated with preoperative irradiation（RS）, and 87 patients underwent adjuvant radiotherapy (RSR). A total of 446 cases of SCMS from June 1985 to December 2008 were managed with unscheduled application of the above 3 kinds of treatment options. The dose of 231 patients with CSR and 128 patients with RS was 60-70Gy/30-35times/5-7week and 40-50gy/20-25times/4-5week, respectively. Dose in RSR accounted for half of that in CSR. The number of cases undergoing total resection of maxilla, subtotal resection of maxilla and extended excision of maxilla were 299, 111 and 36, respectively (13 cases had orbital exenteration). The number of patients with therapeutic radical neck dissection, functional neck dissection and supraomohyoid neck dissection were 49, 73 and 56, respectively. The data was analyzed with SPSS16.0 software package. RESULTS: Five-year survival rate in 446 cases was 45.96% (205/446), and 220 patients died of tumors, among which 84.09% (185/220) of death were due to local recurrences. The 5-year survival rate of CSR, RS, and RSR were 45.88% (106/23), 46.09% (59/128) and 45.97% (40/87), respectively; Totally 83.33% of CSR, 85.71% of RS and 83.72% of RSR died of local recurrences. There was no significant difference in the survival rates among CSR, RS and RSR. CONCLUSIONS: Unscheduled comprehensive treatment have a higher 5-year survival rate in this advanced SCMS. Elective neck irradiation and neck dissection are necessary for medium or advanced squamous cell carcinoma of maxillary sinus. References | Related Articles | Metrics

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Comparison of two different flap designs in removal of impacted wisdom tooth HE Jin-quan,OUYANG Ke-xiong,ZHANG Qing-bin,ZHOU Miao,YANG Zi-nan,PIAO Zheng-guo 2015, 24 (2):  224-227.  Abstract ( 497 )   HTML ( 3 )   PDF (990KB) ( 856 )   PURPOSE: The purpose of this study was to compare the effect of two different flap designs on surgical removal of impacted mandibular third molars. METHODS: Four hundred patients who required removal of impacted mandibular third molars were included in the study. They were divided into group A and group B randomly. Patients in group A received distal incision flap and group B underwent angular incision flap. The effect of flap design on surgical time, incidence of dry socket, pain, swelling and trismus was evaluated postoperatively. Data analysis was carried out with SPSS 13.0 software package. RESULTS: The surgical time was longer in group A than in group B 3 days postoperatively. Facial swelling and trismus were less in group A than in group B 3 days postoperatively. There was no significant difference in two groups 7 days postoperatively. CONCLUSIONS: The distal incision flap design can release facial swelling and trismus in surgical removal of impacted mandibular third molars. References | Related Articles | Metrics

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Expression of Ki-67 and P53 protein in oral squamous cell carcinoma and its clinical significance HE Wei,XIAO Yan,CHEN Wei-min 2015, 24 (2):  228-231.  Abstract ( 398 )   HTML ( 0 )   PDF (1060KB) ( 321 )   PURPOSE: To investigate the clinical and pathological features and its relationship with the expression of Ki-67 and p53 protein in oral squamous cell carcinoma. METHODS: Immunohistochemical SP staining method was used to quantify the protein expression levels of Ki-67 and p53 protein in 10 cases of normal oral mucosa, 16 cases of oral leukoplakia (OLK) tissue, and 48 cases of oral squamous cell carcinoma. The relationship of the expression of Ki-67 and p53 protein to clinical and pathological data was analyzed, and SPSS17.0 software package was used for statistical analysis. RESULTS: The positive expression rate of Ki-67 protein in normal oral mucosa, oral leukoplakia and oral squamous cell carcinoma was 30%, 56.3% and 79.2%, respectively; The positive expression rate of p53 was 0%, 43.8%, and 70.8%, respectively; Ki-67 and p53 expression had significant difference among normal oral mucosa, oral leukoplakia and oral squamous cell carcinoma (P<0.05); The expression of Ki-67 protein was significantly elevated with tumor stage, differentiation and cervical lymph node metastasis (P<0.05); The expression of p53 protein was significantly related to the degree of tumor differentiation (P<0.05); The expression of Ki-67 and p53 was positively correlated in oral squamous cell carcinoma (P<0.05). CONCLUSIONS: The high expression of Ki-67 and p53 protein in oral squamous cell carcinoma tissues may play an important role in the development of oral squamous cell carcinoma. References | Related Articles | Metrics

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Soft tissue linear evaluation of fixed Twin-block appliance treatment and tooth extraction in skeletal Class Ⅱ malocclusion GONG Yao,LI Pei-lun,WANG Hong-hong,YU Quan,WEI Bin,SHEN Gang 2015, 24 (2):  232-235.  Abstract ( 299 )   HTML ( 0 )   PDF (820KB) ( 380 )   PURPOSE: This cephalometric study was designed to evaluate the soft tissue profile effects of Twin-block combined with straight wire appliances to treat growing adolescents with skeletal Class Ⅱ malocclusion and mandibular retrognathia. METHODS: The samples comprised 31 growing individuals with skeletal Class Ⅱ and mandibular retrognathia. They were divided into 2 groups. The study group (18 patients) was treated with fixed Twin-block combined with fixed appliance, while the control group (13 patients) was only treated with fixed appliance after tooth extraction. Pretreatment and posttreatment lateral cephalograms were taken before and after Twin-block treatment and after all the fixed appliance treatment. Linear cephalometric measurements of soft tissue were analyzed statistically. Intragroup and intergroup changes of the 2 groups were evaluated using SPSS 15.0 software package. RESULTS: Significant changes of G'-Pg', Li-1, Si-B and Ls-E line between before and after treatment were found in the study group, while Li-1, Ls-E line and Li-E line changed significantly in control group. The change of Li-E line was different between the 2 groups. CONCLUSIONS: Twin-block combined with fixed appliance treatment is better than extraction with fixed appliance treatment in promoting lower facial profile in cases of skeletal Class Ⅱ malocclusion and mandibular retrognathia with growth potentials. References | Related Articles | Metrics

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Preventive effect of dexmedetomidine on postoperative delirium in elderly patients with oral cancer GUO Yong,SUN Lu-lu,CHEN Zhi-feng,LI Qi-fang,JIANG Hong 2015, 24 (2):  236-239.  Abstract ( 317 )   HTML ( 1 )   PDF (823KB) ( 368 )   PURPOSE: To observe and analyze the preventive effect of dexmedetomidine on postoperative delirium in elderly patients with oral cancer. METHODS: One hundred and fifty-six elderly patients with oral cancer who received radical surgery under general anesthesia were studied. They were randomly divided into 2 groups: experimental group (n=78) and control group (n=78). All patients stayed in PACU for 2 hours after surgery, and then were transferred to SICU when they had waken up. Subsequently, patients in experimental group were assigned to take intravenous dexmedetomidine at a dose of 0.2μg/kg.h for 12 hours while patients in control group were assigned to take intravenous normal saline for 12 hours. All patients were given compound analgesia consisted of tramadol and tropisetron in the same dose. During the first three postoperative days, patients were evaluated with the Confusion Assessment Method for the Intensive Care Unit (CAM-ICU), Visual Analogue Scale and Richmond Agitation Sedation Scale twice a day(8:00 am and 8:00 pm). Statistical analysis was performed using SPSS16.0 software package. RESULTS: There was no significant difference on postoperative VAS, the incidence of postoperative bradycardia and hypotension between 2 groups. In addition, no postoperative respiratory depression was found in 2 groups. Richmond Agitation Sedation Scale on the first and second day after surgery in the experimental group was better than in the control group. The incidence of postoperative delirium, nausea and vomiting in the experimental group was lower than in the control group. CONCLUSIONS: Intravenous dexmedetomidine at a dose of 0.2μg/kg.h for 12 hours after operation in elderly patients with oral cancer can ameliorate postoperative sedation status, reduce the incidence of postoperative delirium, and will not cause postoperative bradycardia, hypotension and other complications. References | Related Articles | Metrics

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Correlation analysis between psychosomatic symptoms of adult and cooperation behaviors ZHENG De-hua,WANG Xu-xia,ZENG Jing,SUN Xin-guo,XU Chao,ZHANG Jun 2015, 24 (2):  240-244.  Abstract ( 217 )   HTML ( 0 )   PDF (849KB) ( 272 )   PURPOSE: To investigate whether the psychosomatic symptoms of patients are related to the degree of cooperation. METHODS: Ninety-one malocclusion adults (31 males, 60 females, aged from 20 to 45 years) were selected and determined with Symptom Checklist-90 (SCL-90) to evaluate their psychosomatic symptoms. The inspected and filed noncooperation behaviors were examined and recorded 6 months after orthodontic treatment started. The data was analyzed by one-sample t test, independent-sample t test and Spearman rank correlation coefficient with SPSS 20.0 software package. RESULTS: Adult malocclusion patients scored significantly higher than the nation norm on the factors of interpersonal sensitivity, anxiety, schizophrenia and compulsion (P<0.05). The score of noncooperation behaviors showed a scale of 0 to 19, with an average of 7.2±1.4 points. There was positive correlation between psychological problems and noncooperation behaviors of adult patients (r=0.35). CONCLUSIONS: The study confirms that the psychosomatic symptoms of adult malocclusion patients are associated with the degree of cooperation. Having known well about the psychology of adult malocclusion patient before orthodontic treatment is initiated, and orthodontists can relieve psychological disorders in patients to improve their cooperating quality. References | Related Articles | Metrics

Clinical Reports

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Evaluation of labial surface root filling combined with porcelain dental restoration LIU Yuan-qiao,HUANG Zhi-hua,HU Huan-yu 2015, 24 (2):  245-248.  Abstract ( 208 )   HTML ( 0 )   PDF (1025KB) ( 198 )   PURPOSE: To analyze the effect of porcelain dental restoration combined with labial surface root filling for the anterior teeth. METHODS: One hundred cases with anterior teeth protrusion treated in our department from January 2010 to January 2014 underwent porcelain dental restoration combined with labial surface root filling. The measurements in cephalometric X-ray films before and after treatment were compared, and porcelain dental appearance and function were evaluated. The data was statistically analyzed with SPSS18.0 software package. RESULTS: After treatment, U1-SN, U1-X, U1-Y were significantly lower than before treatment（P<0.01）. U1-L1 was significantly higher after treatment（P<0.01）. The incidence of gingivitis after treatment decreased significantly（χ2=16.2749,P=0.0000<0.01）. The excellent rate of outline of porcelain teeth after treatment, correction of protruding anterior teeth, fitting with adjacent teeth and alleviation of deep overbite and deep cover was 96.00%, 95.00%, 98.00% and 91.00%, respectively. CONCLUSIONS: Porcelain dental restoration after root canal treatment can effectively improve anterior teeth protrusion and increase the aesthetic appearance, which is worthy of clinical application. References | Related Articles | Metrics

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Application of miniscrew for extraction of mesially impacted wisdom tooth adjacent to the inferior alveolar nerve canal MA Xiao-qing,FAN Jian-fen,XU Pei-cheng,XIANG Fei,QIN Fei 2015, 24 (2):  249-252.  Abstract ( 239 )   HTML ( 0 )   PDF (1224KB) ( 326 )   PURPOSE: To study the value of miniscrew for extraction of mesially impacted wisdom tooth adjacent to the inferior alveolar nerve canal. METHODS: Fourteen mesially impacted wisdom teeth were proven to be adjacent to the inferior alveolar nerve canal by means of cone-beam CT scan. The treatment began with the miniscrew traction of the wisdom teeth. After 2~5 months, they were moved away from the canal and then extracted. RESULTS: After extraction, all 14 cases did not show any obvious side effect. CONCLUSIONS: Application of miniscrew traction is a valuable method for minimally invasive extraction of mesially impacted wisdom tooth that is adjacent to the inferior alveolar nerve canal. References | Related Articles | Metrics

Dental Education

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Analysis and reflections of dental qualification examination for oversea dentists in Beijing ZHANG Dong,SHEN Shu-ming 2015, 24 (2):  253-256.  Abstract ( 226 )   HTML ( 0 )   PDF (814KB) ( 263 )   PURPOSE: To improve the management of qualification examination for oversea dentists in Beijing based on analysis of examinations during 2000-2013. METHODS: The information of examinees for qualification examination of oversea dentists during 2000-2013 were collected and analyzed in Beijing. RESULTS: Among 142 examinees from 21 countries, China Hong Kong and Taiwan region, the pass rate was 48.2% for general dentists and 66.7% for dental specialists. The pass rate was highest among examinees whose native language was English or Chinese. CONCLUSIONS: For oversea dentists who participate in the qualification examination in Beijing, besides the knowledge and skills, much more attention should be paid to prepare the examination and improve the Chinese or English language ability. References | Related Articles | Metrics