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    15 January 2016, Volume 20 Issue 3 Previous Issue    Next Issue
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    Novel lithium chloride/calcium phosphate cement: physicochemical and osteogenic properties 
    Li Li, Li Bai-chuan, Wang Ren-chong, Li Bing
    2016, 20 (3):  307-313.  doi: 10.3969/j.issn.2095-4344.2016.03.001
    Abstract ( 436 )   PDF (4460KB) ( 752 )   Save

    BACKGROUND: Lithium chloride is a widely used inorganic ion inhibitor of glycogen synthase kinase-3β, and it can be combined with glycogen synthase kinase-3β to activate the classical Wnt/β-catenin pathway, thereby promoting human bone marrow mesenchymal stem cells and osteoblasts proliferation and accelerating bone repair.
    OBJECTIVE: To observe the physicochemical properties of novel lithium chloride/calcium phosphate cement, and to explore its osteoinductive biological property.
    METHODS: Calcium phosphate cement served as control group, and lithium chloride/calcium phosphate cement containing different lithium content as experimental groups. The setting time and compressive strength of bone cement in each group were detected, and the microstructure of the material surface observed under scanning electron microscopy. Bone cement and MC3T3-E1 cells were co-cultured in vitro, and the growth and adhesion morphology of MC3T3-E1 cells on the surface of bone cement were observed under the scanning electron microscope. Effect of bone cement extracts on cell proliferation was determined through MTT assay, and alkaline phosphatase kit used for determining alkaline phosphatase activity.
    RESULTS AND CONCLUSION: Lithium chloride/calcium phosphate cement had the same physicochemical properties to the calcium phosphate cement. Initial and final setting time, compressive strength and morphology of bone cement had no significant differences among groups. MC3T3-E1 cells grew and adhered well on the material surface. Results of MTT assay showed that compared with the calcium phosphate cement, the lithium chloride/calcium phosphate cement was better to improve osteoblast proliferation in vitro. In addition, the alkaline phosphatase activity in MC3T3-E1 cells was higher in experimental groups than the control group. These findings indicate that lithium chloride/calcium phosphate cement can maintain good physicochemical properties, and release lithium ions to promote bone formation.
     

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    Autogenous bone, recombinant human bone morphogenetic protein 2 composite bone or allogeneic bone in rabbit lumbar spinal fusion
    Zhang Ke, Peng Qiang
    2016, 20 (3):  314-318.  doi: 10.3969/j.issn.2095-4344.2016.03.002
    Abstract ( 308 )   PDF (1023KB) ( 308 )   Save
    BACKGROUND: Recombinant human bone morphogenetic protein 2 (rhBMP2) can effectively promote new 
    bone formation and fracture healing, but its specific application in the lumbar spinal fusion remains controversial.
    OBJECTIVE: To study the effect of autogenous bone, rhBMP2 composite bone or allogeneic bone on the lumbar spinal fusion of rabbits. 
    METHODS: Forty-five New Zealand white rabbits were enrolled to make intertransverse lumbar interbody fusion models and then randomly subjected to autogenous iliac bone, rhBMP2 composite bone or allogeneic iliac bone via L5-L6 intertransverse process, respectively. Then, the rats were sacrificed under anesthesia at 8 weeks after operation to observe the lumbar fusion.
    RESULTS AND CONCLUSION: Compared with the allogeneic iliac bone group, the fusion rates, tensile strength ratio of L5-6/L4-5, and percentage of new bone tissues were increased more significantly in the other two groups  (P < 0.05), and moreover, there was no difference between the autogenous iliac bone and rhBMP2 composite bone groups. These findings indicate that the autogenous iliac bone and rhBMP2 composite bone have similar fusion effects, both of which are superior to the allogeneic bone.
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    Effect of antibiotic-loaded bone cement on erythrocyte sedimentation rate, C-reactive protein level and joint function of patients undergoing total knee arthroplasty
    Li Guo-hua, Ding Li-ming, Zhang Bin, Qiu Jing, Liu Han
    2016, 20 (3):  319-323.  doi: 10.3969/j.issn.2095-4344.2016.03.003
    Abstract ( 244 )   PDF (879KB) ( 263 )   Save

    BACKGROUND: Antibiotic-loaded bone cement for artificial joint fixation can locally play the anti-inflammatory effects of antibiotics, thereby preventing the occurrence of infection.
    OBJECTIVE: To investigate the effect of antibiotic-loaded bone cement on erythrocyte sedimentation rate, C-reactive protein and joint function of patients treated by total knee arthroplasty.
    METHODS: Totally 86 patients, including 43 males and 43 females, aged 45-75 years, were enrolled and divided into observation and control groups (n=43/group). The artificial knee joints of patients in the
    observation group were fixed with antibiotic-loaded bone cement, while the artificial knee joints of patients in the in the control group were fixed with conventional bone cement. The surgical condition, blood indexes, knee function and therapeutic efficacy were compared between these two groups.
    RESULTS ADN CONCLUSION: The bed time and incidence of infection after operation in the observation group were significantly lower than those in the control group (P < 0.05); the knee bending angle and total efficiency of treatment after 2 weeks of treatment were significantly higher than those in the control group (P < 0.05). The C-reactive protein level and erythrocyte sedimentation rate at 3 and 7 days after treatment in these two groups were significantly decreased compared with those before treatment (P < 0.05), especially in the observation group (P < 0.05). The knee joint function scores after 6 months of treatment in these two groups were significantly increased compared with those before treatment (P < 0.05), especially in the observation group (P < 0.05). These results demonstrate that antibiotic-loaded bone cement is conductive to prevent the occurrence of infections, improve blood indexes and promote the knee joint function recovery. 

     

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    Wisker-covered porous calcium phosphate ceramics in repair of canine femoral condyle defects
    Zhou Chao-xi, Cui Xu, Ao Guo-kun, Xu Tao-tao, Weng Jie, Xiao Zhan-wen, Zhang Xing-dong, Zhang Cong
    2016, 20 (3):  324-329.  doi: 10.3969/j.issn.2095-4344.2016.03.004
    Abstract ( 346 )   PDF (5853KB) ( 687 )   Save

    BACKGROUND: Previous studies have demonstrated that the internal microstructure of porous calcium phosphate ceramics after the whiskering process has some changes, and obtain good mechanical properties.
    OBJECTIVE: To further investigate the effect of whisker-covered porous calcium phosphate ceramics in repair of canine femoral condyle defects.
    METHODS: Highly interconnected porous calcium phosphate ceramics was prepared by placeholder method. The whiskering of the materials was finished by hydrothermal process. Fifteen healthy adult beagle dogs were selected in this study. A 10 mm×10 mm cylindrical inclusive bone defect was made bilaterally on the lateral femoral condyle with a drill. The porous calcium phosphate ceramics after the whiskering process was implanted onto the right femoral condyle as experiment group. The porous calcium phosphate ceramics without the whiskering process was implanted onto the left femoral condyle as control group. At 2, 4, 8, and 12 weeks after implantation, X-ray and dual-energy X-ray test were conducted in the bone defect area respectively.
    RESULTS AND CONCLUSION: (1) X-ray: With the increase of time, the interface between bone defect and normal bone of two groups gradually blurred, disappeared, and completely fused at 12 weeks. The material in the control group was partially dissolved, while there was no obvious dissolution in the experiment group. No significant difference in the X-ray scores was found between two groups at different time points. (2) Dual-energy X-ray: With the increase of time, the bone mineral density of the two groups both increased gradually, but there was no significant difference in the bone mineral density at different time points between these two groups. These results demonstrate that the porous calcium phosphate ceramics after the whiskering process has good ability to repair the defects of femoral condyle.
     

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    Degradation performance of the digital coralline hydroxyapatite artificial bone scaffold in vitro
    Lin Shan, Huang Xiao-mei, Rui Gang, Yin Qing-shui
    2016, 20 (3):  330-335.  doi: 10.3969/j.issn.2095-4344.2016.03.005
    Abstract ( 379 )   PDF (5475KB) ( 382 )   Save

    BACKGROUND: We have successfully prepared the digital coralline hydroxyapatite artificial bone scaffold in previous experiments, and it has good physicochemical properties and biocompatibility.
    OBJECTIVE: To evaluate the in vitro degradation performance of the digital coralline hydroxyapatite artificial bone.
    METHODS: We used the mixtures of coralline hydroxyapatite and L-polylactic acid at the mass ratio of 3:1 and 4:1 as raw materials to prepare the digital coralline hydroxyapatite artificial bone scafflold specimens, and then they were immersed in the 50 mL stimulated body fluid with the initial pH value of 7.4 in an incubator at 37 ℃ for degradation. After 16 weeks of degradation, the pH value, calcium and phosphate ion concentration, degradation rate, compressive strength and changes of microstructure were dynamically observed.
    RESULTS AND CONCLUSION: At the 16th weeks of degradation, the pH values in the two kinds of digital artificial bone groups maintained at 7.34-7.36, which were higher than that in the L-polylactic acid group (P < 0.01), and lower than that in the coralline hydroxyapatite group (P < 0.01). The calcium ion concentrations in the two kinds of digital artificial bone groups were higher than that in the coralline hydroxyapatite group (P < 0.01), and the phosphorus ion concentrations were lower than that in the coralline hydroxyapatite group (P < 0.01). The degradation rates in the two kinds of digital artificial bone groups were lower than that in the coralline hydroxyapatite group (P < 0.01), and higher than that in the L-polylactic acid group (P < 0.01). The order of the compressive strength was as follows: coralline hydroxyapatite group > 3:1 digital artificial bone group > L-polylactic acid group > 4:1 digital artificial bone group. The cellular structure, porosity and pore size in the two kinds of digital artificial bone groups were all increased. These results show that the prepared digital coralline hydroxyapatite artificial bone scaffold has good degradation propertyies. 

     

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    Preparation and characterization of cuttlebone/racemic polylactic acid composite artificial bone materials 
    Wang Wei, Xiao Rong-chi, Han Xiao-wei, Qin Guang-bing, Xiao Ying, Ou Jun
    2016, 20 (3):  336-340.  doi: 10.3969/j.issn.2095-4344.2016.03.006
    Abstract ( 311 )   PDF (2287KB) ( 484 )   Save

    BACKGROUND: Cuttlebone which is rich in calcium has a natural affinity with the nature bone tissue. However, when the cuttlebone is applied as supporting material independently, its brittleness is larger and the intensity is lower.
    OBJECTIVE: To independently research and develop cuttlebone/racemic polylactic acid composite artificial bone tissue scaffolds, and detect their various performance.
     
    METHODS: The composite artificial bone was prepared by combining the cuttlebone and racemic polylactic acid at the weight ratio of 1:2, 2:1 and 1:1 using salting out method. The pure cuttlebone was taken as control. The microstructure, porosity, water binding force, biological mechanics and in vitro degradation performance were determined.
    RESULTS AND CONCLUSION: The surface of cuttlebone had spine shape, clear texture and cellular distribution. Composite artificial bone was similar to the cancellous bone, whose big pore diameter was 500-1 500 μm and small pore diameter was 150-300 μm. Composite artificial bone had less micropores, and the connectivity between the holes is good. The bending strength, the elastic modulus, in vitro degradation properties of these three kinds of composite artificial bone were better compared with cuttlebone (P < 0.05), porosity was less than that of cuttlebone (P < 0.05), and there were no significant differences between these composite artificial bone groups. There was no significant difference in the water binding force between these four groups. These results demonstrate that cuttlebone/racemic polylactic acid composite artificial bone has good microstructure, mechanical properties and degradation performance. 

     

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    In vitro cytotoxicity of SuperBond C&B, a resin cement for dental bonding
    Jiang Xian-min, Zhao Xi
    2016, 20 (3):  341-345.  doi: 10.3969/j.issn.2095-4344.2016.03.007
    Abstract ( 492 )   PDF (3862KB) ( 458 )   Save

    BACKGROUND: Because of long-term contact with tooth tissues, gingival tissues and saliva in the mouth, oral bonding materials must have the characteristics of biological safety and low or no cytotoxicity, so as to ensure no irritation response to the oral mucous and no toxicity and allergic reactions when contacting with human tissues.
    OBJECTIVE: To observe the in vitro cytotoxicity of an oral bonding material, SuperBond C&B.
    METHODS: The logarithmic human periodontal ligament fibroblasts were obtained and inoculated in 96-well plates with a cell concentration of 1.0×108/L, 100 μL/hole. Supernatant was removed after 24 hours of routine culture, and the specimens were grouped and cultured. 90 μL DMEM culture liquid+10 μL SuperBond C&B were added in the experimental group. 100 μL medium was added in the negative control group. 100 μL phenol solution was added in the positive control group. After 72 hours of culture, the cell survival rate in each group was calculated by trypan blue exclusion test.
    RESULTS AND CONCLUSION: The cell survival rates of the experimental group and the negative control group were higher than that of the positive control group (P < 0.05), and there was no significant difference between the experimental group and the negative control group (P > 0.05). These results show that SuperBond C&B has no cytotoxicity.   

     

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    A three-dimensional polylactic acid scaffold pretreated with bone morphogenetic protein 7
    Bei Kang-sheng, Liu Yan-xiao, Xiong Ying-hui, Wu Li-yang, Lu Lin-jun
    2016, 20 (3):  346-351.  doi: 10.3969/j.issn.2095-4344.2016.03.008
    Abstract ( 362 )   PDF (5696KB) ( 583 )   Save

    BACKGROUND: To improve the cell affinity of polylactic acid, the three-dimensional polylactic acid scaffold is made after pretreatment with bone morphogenetic protein 7 (BMP7).
    OBJECTIVE: To evaluate the compatibility of BMP7-pretreated three-dimensional polylactic acid scaffold with 
    periosteum-derived cells. 
    METHODS: Passage 3 human periosteum-derived cells undergoing osteogenic induction at a density of 1×109/L were seeded into culture media containing the three-dimensional polylactic acid scaffold (experimental group) or seeded into simple culture media (control group). In the experimental group, the scaffold was pretreated with BMP7 for 24 hours. At 1, 3, 5, 7, 9, 11 days after culture, cell counting kit-8 method was used to measure cellular proliferation; at 3, 6, 9, 12 days, the cell-scaffold complex was observed under an electron microscope.
    RESULTS AND CONCLUSION: In the two groups, the cells had an S-shaped growth curve. Compared with the control group, the cell proliferation in the experimental group was faster at the logarithmic phase, but slower at the stationary phase (P < 0.05). Under the transmission electron microscope, in the experimental group, the number of adherent cells was increased gradually, and the cells grew well with exuberant organelles at 3-6 days of co-culture, but cell aging and apoptosis were found at 9 days of co-culture. Under the scanning electron microscope, in the experimental group, the number of adherent cells on the scaffold surface gradually increased at 3-9 days of co-culture, and then cell apoptosis was notable at 12 days. These findings indicate that BMP7-pretreated three-dimensional polylactic acid scaffold has good cytocompatibility, and the optimal in vitro co-culture duration is 1 week.

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    Construction of animal models induced by platelet-rich fibrin
    Xiao Qiong, Sun Yong, Chen Hong-liang, Zhao Feng, Dong Lu, Yang Qin-qiu, Lu Shuai
    2016, 20 (3):  352-358.  doi: 10.3969/j.issn.2095-4344.2016.03.009
    Abstract ( 322 )   PDF (6014KB) ( 629 )   Save

    BACKGROUND: At present, many studies have focused on platelet-rich fibrin combined with other bone substitute materials in repair of peri-implant bone defects and sinus lifting, but there is still a lack of research 
    about the platelet-rich fibrin alone in repair of critical-size bone defects.
    OBJECTIVE: To compare the effect of three kinds of bone substitutes, platelet-rich fibrin, Bio-Oss bone substitute and autogenous cancellous bone, in repair of bone defects.
    METHODS: Four areas of cylindrical critical bone defects with a diameter of 6.0 mm and depth of 10.0 mm were prepared in the medial femoral condyle of beagle dogs. Three areas of bone defects were implanted with autologous platelet-rich fibrin, Bio-Oss bone substitutes and autologous cancellous bone, respectively. The remaining one area of bone defect was not implanted any substance, as control group. X-ray and Micro-CT detections in bone defect area were conducted after 12 weeks of surgery.
    RESULTS AND CONCLUSION: (1) X-ray: the density of platelet-rich fibrin group was more higher, but still slightly lower than that of the surrounding normal bone tissue; the density of the Bio-Oss bone substitute group was more lower, but still higher than that of the surrounding bone tissues; the density of autologous cancellous bone group was more higher, which was close to that of the surrounding bone tissues; circular low-density images were visible in the control group. (2) Micro-CT: platelet-rich fibrin group was similar with the autogenous cancellous bone group, and their density was slightly lower than that of the surrounding normal bone tissues; the trabecular bone exlibited a clear regular arrangement, and no obvious interface; the Bio-Oss bone substitute group showed a high density image with clear interface; the bone defect area was still clearly visible in the control group, with a low-density image. The bone volume fraction and trabecular number in the platelet-rich fibrin and autologous cancellous bone groups were both higher than those in the Bio-Oss bone substitute group (P < 0.05). These results demonstrate that platelet-rich fibrin and autogenous cancellous bone have a similar bone repair effect. 

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    Effect of brominated furanones on the formation of Staphylococcus epidermidis biofilm on the surface of polyvinyl chloride material
    Cheng Peng, Ye Lian-hua, Huang Yun-chao, Xu Geng, Zhao Guang-qiang, Guo Feng-li,Qiu Liang-ting
    2016, 20 (3):  359-363.  doi: 10.3969/j.issn.2095-4344.2016.03.010
    Abstract ( 384 )   PDF (7042KB) ( 612 )   Save

    BACKGROUND: Quorum sensing system plays a very important role in the formation of bacterial biofilm. Most of brominated furanones blocked the quorum sensing of bacteria after combining with the receptors of autoinductors in sensing system, however, some brominated furanones play a role of bacterial autoinductors and promote the formation of bacterial biofilm.
    OBJECTIVE: To investigate the influence of different types of brominated furanones on the biofilm formation of Staphylococcus epidermidis on the surface of polyvinyl chloride materials.
    METHODS: Polyvinyl chloride materials were divided into control group and furanone 1-3 groups. The polyvinyl chloride materials in the control group were soaked with ethanol for 5 minutes. Three kinds of brominated furanones with representative chemical structure were taken as furanone 1-3 groups which were respectively 3,4-dibromo-5-hydroxyl-furanone,4-bromo-5-(4-methoxypheny)-3-(methylamino)- furanone and 3,4-dibromo-5,5-dimethoxypheny-2(5H)-furanone. The surface coating of the polyvinyl chloride materials in these four groups all underwent modification and then were co-cultivated with Staphylococcus epidermidis together.
    RESULTS AND CONCLUSION: Compared with the control group, Staphylococcus epidermidis bacterium community quantity on the surface of polyvinyl chloride material was smaller, and the thickness of bacterium biofilm in furanone-2 group was thinner. There was no obvious bacterial biofilm structure formation on the surface of polyvinyl chloride material at the 18th hour of culture. The Staphylococcus epidermidis bacterium community quantity and the thickness of bacterium biofilm in furanone 1 and furanone 3 groups were closer to the control group. These results show that the impact of different types of brominated furanones on biofilm formation of Staphylococcus epidermidis on the surface of polyvinyl chloride materials is different, among them, 4-bromo-5-(4-methoxypheny)-3-(methylamino)-furanone can inhibit the growth of Staphylococcus epidermidis and the bacterial biofilm formation on the surface of polyvinyl chloride materials. 

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    In vitro destructive effect of ultrasound on Staphylococcus aureus biofilms
    Zhang Wei, Wei Peng, Chen Lu
    2016, 20 (3):  364-369.  doi: 10.3969/j.issn.2095-4344.2016.03.011
    Abstract ( 526 )   PDF (4771KB) ( 640 )   Save
    BACKGROUND: Studies have shown that the ultrasound enhances the on bactericidal activity of antibiotics in an intensity-dependent manner, that is, the higher the ultrasound intensity, the greater its effectiveness.
    OBJECTIVE: To study the destructive effect of different intensities of ultrasound on Staphylococcus aureus and its biofilm.
    METHODS: Staphylococcus aureus biofilms were cultured in vitro using guide sheet culture method and divided into three groups for intervention. The biofilm in the control group received no treatment. The biofilm in the low-intensity ultrasound group was intervened by pulsed ultrasound with an intensity of 500 mW/cm and frequency of 200 kHz for 10 minutes. The biofilm in the high-intensity ultrasound group was intervened by continuous ultalsound with an intensity of 40 W and frequency of 1 MHz for 10 minutes. Bacterial colonies were counted using ultrasonic oscillation-live bacteria counting method. DNA and polysaccharide of the bacteria were respectively marked using propidium iodide and FITC-ConA. The molding of the bilfilm was determined using laser scanning confocal microscope.
    RESULTS AND CONCLUSION: The number of bacterial colonies in the high-intensity ultrasound group were lower than that in the control and low-intensity ultrasound groups (P < 0.05), and there were no significant differences between control and low-intensity ultrasound groups. There were no significant differences in the number and intensity of red fluorescence and green fluorescence between low-intensity ultrasound and control groups; however, the number and intensity of red fluorescence and green fluorescence in the high-intensity ultrasound group were significantly decreased compared with the low-intensity ultrasound and control groups. These results demonstrate that the low-intensity ultrasound cannot kill the bacteria and it has a tiny destructive effect on the biofilm of bacteria; however, the high-intensity ultrasound can effectively kill the bacteria and has a strong destructive effect on the bilfilm of bacteria. 
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    Biocompatibility of ZrO2 and Al2O3 ceramic composites in dentistry
    Deng Shu-nan, Huang Hong-yan, Zhan De-song, Liang Zai-fu
    2016, 20 (3):  370-376.  doi: 10.3969/j.issn.2095-4344.2016.03.012
    Abstract ( 362 )   PDF (1284KB) ( 440 )   Save

    BACKGROUND: The physiological environment of oral cavity is very complex. Dental restoration materials exposed to the weakly acidic body fluids in the long term, and were in the complex influences including physical, chemical, biological and mechanical and other factors. Therefore, the evaluation of biocompatibility for dental materials is the focus of research before entering the clinical trials, and also the important technical indicators to 
    ensure the clinical safety.
    OBJECTIVE: To preliminarily evaluate the biocompatibility of ZrO2 and Al2O3 ceramic composites.
    METHODS: The experiment was divided into six groups: ZrO2 and Al2O3 (1:1) 100% extract group, ZrO2 and Al2O3 (1:1) 50% extract group, ZrO2 and Al2O3 ( 4:1) 100% extract group, ZrO2 and Al2O3 (4:1) 50% extract group, and the volume fraction of 0.64% phenol positive control group and 100% fresh medium of negative control group. Acute hemolysis and in vitro cytotoxicity experiments were conducted according to the biological evaluation standards and requirements of GB-T16886 15-2003 medical devices. The effects of the above six groups of extracts on rabbit blood cells and L-929 mouse fibroblast cells were tested respectively.
    RESULTS AND CONCLUSION: There was no significant difference in the absorbance values between different concentrations of experimental groups and negative control group (P > 0.05). The cytotoxicity rating of all experimental groups was 0-1 grade. The hemolysis rates in the ZrO2 and Al2O3 (1:1) 100% extract and ZrO2 and Al2O3 (4:1) 100% extract groups were 1.27% and 2.4% respectively, less than the accepted safety standards of 5%. These results demonstrate that the acute hemolytic experiment and in vitro cytotoxicity experiment of (1:1), (4:1) ZrO2 and Al2O3 ceramic composites are all negative, and all have good cytocompatibility and blood compatibility.  

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    Casein phosphopeptides/amorphous calcium phosphate compound and fluoride prevent enamel demineralization around orthodontic brackets
    Luo Hui, Jia De-jiao, Liu Hai-xia, Fan Ya-ru, Zhao Hao-ran
    2016, 20 (3):  377-381.  doi: 10.3969/j.issn.2095-4344.2016.03.013
    Abstract ( 430 )   PDF (1686KB) ( 317 )   Save

    BACKGROUND: In clinical practice, both casein phosphopeptides/amorphous calcium phosphate compound and fluoride can effectively prevent the occurrence of enamel demineralization and caries.
    OBJECTIVE: To investigate the preventive effects of casein phosphopeptides/amorphous calcium phosphate compound and fluoride on enamel demineralization in the orthodontic treatment, so as to seek a remineralization agent with good effect.
    METHODS: Totally 40 human in vitro teeth which had been well bonded to brackets were randomly divided into four groups: control group (the surface was not coated with any substance), GC tooth mousse group (the surface was coated with casein phosphopeptides/amorphous calcium phosphate compound), duraphat group (the surface was coated with fluoride) and combined group (the surface was coated with casein phosphopeptides /amorphous calcium phosphate compound and fluoride). The enamel surface porosity was observed by scanning electron microscopy after the successive 14-day demineralization-remineralization experiments in these four groups. The change value of microhardness was measured before and after the experiment in each group.
    RESULTS AND CONCLUSION: There was obvious enamel demineralization in the control group, but not in the other three groups. The change value of microhardness in GC tooth mousse, duraphat and combined groups was lower than that in the control group (P < 0.05), and there was no significant difference between GC tooth mousse, duraphat and combined groups. These results demonstrate that fluoride, casein phosphopeptides/amorphous calcium phosphate compound and their combination can prevent enamel demineralization, promote remineralization; however, their combination does not improve the effect of preventing enamel demineralization. 
      

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    Apical micro-leakage after apical barrier using mineral trioxide aggregate
    Li Hao-bo, Du Yong
    2016, 20 (3):  382-386.  doi: 10.3969/j.issn.2095-4344.2016.03.014
    Abstract ( 298 )   PDF (978KB) ( 299 )   Save

    BACKGROUND: Because of its good sealing property and biocompatibility, mineral trioxide aggregate can promote the regeneration of bone tissue, induce the differentiation of periodontal cells. and reduce the apical micro-leakage.
    OBJECTIVE: To compare the micro-leakage of hot gutta-percha filling after mineral trioxide aggregate apical barrier and continuous hot gutta-percha filling techniques.
    METHODS: Totally 36 in vitro single root canal molars were selected and randomly divided into experimental and control groups. In the experimental group, mineral trioxide aggregate apical barrier was conducted, and then hot gutta-percha root canal filling was conducted after operation. Continuous wave of hot gutta-percha root canal filling was conducted in the control group. The apical micro-leakage was detected by glucose oxidase method.
    RESULTS AND CONCLUSION: The root canals were successfully and tightly sealed in these two groups. The apical micro-leakage gradually increased with the time. In the experimental group, the apical micro-leakage values at 1, 7, 14, 21 and 28 days of filling were all significantly lower than those in the control group (P < 0.05). These results demonstrate that hot gutta-percha root canal filling has a relatively good apical sealing effect after the mineral trioxide aggregate apical barrier, and can significantly reduce micro-leakage.
     

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    Effects of different implant-abutment connections on aesthetic restoration of single maxillary anterior teeth 
    Hou Hong-liang, Dai Xiao-wei, Wang Li, Li Ke, Ji Tao, Wang Jian-qing, Li Shu-hui, Wu Pei-ling
    2016, 20 (3):  387-391.  doi: 10.3969/j.issn.2095-4344.2016.03.015
    Abstract ( 376 )   PDF (915KB) ( 332 )   Save

    BACKGROUND: Implant-abutment connection has become a key factor in the success of implant restoration, but 
    the effects of different implant-abutment connections on peri-implant tissues is unclear.
    OBJECTIVE: To compare the effects of three different implant-abutment connections on the alveolar bone and peri-implant soft tissues at the maxillary esthetic zone.
    METHODS: Sixty patients undergoing aesthetic restoration of single maxillary anterior tooth were enrolled randomly, including 20 cases of Bego Replace system, 20 of Osstem Replace system, and 20 cases of ITI Replace system. All the patients had a follow-up of 3 to 6 months after the surgery, and then received the two-stage surgery. Radiographic and clinical examinations were made at the same time. Peri-implant bone height measured was used as the reference line. The final crowns were made after 2 weeks, and the peri-implant bone resorption and pink esthetic scores were evaluated after 12 months shown through X-ray films.
    RESULTS AND CONCLUSION: There were significant differences in peri-implant marginal bone loss and pink esthetic scores among different groups after implant restoration. The amount of marginal bone loss around implants using platform switching was significantly less than that using platform butt-joint (P < 0.0.5), and the pink esthetic scores of the former group was higher than the later one (P < 0.05). These findings indicate that aesthetic restoration of a single maxillary tooth implant using platform switching is able to preserve better marginal bone and acquire better aesthetic effects.
     

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    Preparation of porous nano-hydroxyapatite/polyamide composites for bone repair
    Qiangbashanzeng, Liu Xiao-lan
    2016, 20 (3):  392-396.  doi: 10.3969/j.issn.2095-4344.2016.03.016
    Abstract ( 420 )   PDF (1136KB) ( 360 )   Save

    BACKGROUND: Compared with dense bone repair materials, porous materials has lower intensity, but its three-dimensional porous network structure can ensure a larger surface area that is more conducive to cell adhesion, growth and division as well as nutrient transmission.
    OBJECTIVE: To investigate the preparation and performance of porous nano-hydroxyapatite/polyamide composites.
    METHODS: Porous nano-hydroxyapatite/polyamide composites were prepared using chemical foaming method, and different composite bone repair materials were made by regulating foaming agent amount and nano-hydroxyapatite content. Mechanical properties, porosity and composition of the composite bone repair materials were detected.
    RESULTS AND CONCLUSION: Porous nano-hydroxyapatite/polyamide composites were substantially tubular 
    channels, and had relatively good connectivity and uniform distribution, with a pore size of 260-400 μm, porosity of 35%-57%. Foaming agent amount, nano-hydroxyapatite content and density of composite materials all are influential factors of the total porosity. Porous nano-hydroxyapatite/polyamide composites have better mechanical properties and compressive strength than the cancellous bone, and the foaming agent has no influence on its shape, composition and diffraction peaks. 

     

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    Nano-hydroxyapatite/polyamide 66 composite vertebrae repair anterior cervical vertebral fractures
    Wang Gao-ju, Wang Qing, Yang Jin, Wang Song, Zhong De-jun, Xu Shuang
    2016, 20 (3):  397-401.  doi: 10.3969/j.issn.2095-4344.2016.03.017
    Abstract ( 336 )   PDF (1108KB) ( 291 )   Save
    BACKGROUND: Nano-hydroxyapatite crystals are highly similar to human bone hydroxyapatite crystals in the shape, size, component, structure and crystallinity, and have an analogous elasticity modulus compared with human cortical bone. The application of nano-hydroxyapatite is increasingly widespread in medical field because 
    of excellent osteoconduction, biocompatibility, bioactivity and high strength and toughness.
    OBJECTIVE: To evaluate the primary efficacy of nano-hydroxyapatite/polyamide 66 composite bioactive artificial vertebral body for anterior column reconstruction in cervical vertebral fractures.
    METHODS: A total of 78 patients with cervical vertebral fracture combined with quadriplegia admitted at the Department of Spine Surgery, the First Affiliated Hospital of Sichuan Medical University in China underwent anterior cervical corpectomy decompression, bone grafting and nano-hydroxyapatite/polyamide 66 composite bioactive artificial vertebral body fixation.
    RESULTS AND CONCLUSION: The surgery was sucessful in all patients. Totally 67 patients were followed up. During the follow-up of 4-39 months, X-ray and MRI examinations showed no obvious displacement of the implants, and less loss of cervical physiological sequence and vertebral body height. The spinal function recovered to varying degrees after internal fixation. These results suggest that the application of nano-hydroxyapatite/ polyamide 66 composite bioactive artificial vertebral body in anterior cervical vertebral fractures can increase the area of bone graft fusion, decrease local intensity of pressure and prevent the loosening and sinking of the implants. The initial supporting and stability can effectively maintain cervical physiological sequence and intervertebral height. The bone graft fusion is higher after the internal fixation. It is easy for the X-ray observation, and meanwhile, there is no influence on the MRI scanning for observation of signals of the spinal cord. 

     
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    Construction and performance of a dexamethasone/polycaprolactone collagen scaffold
    Wang Wei, Qi She-ning, Zhao Hong-bin, Li Zhen-jun, Li Gen, Zhang Xiao-min, Song Xue-wen
    2016, 20 (3):  402-407.  doi: 10.3969/j.issn.2095-4344.2016.03.018
    Abstract ( 306 )   PDF (1325KB) ( 332 )   Save

    BACKGROUND: Tissue engineering scaffold materials have been widely used in all kinds of tissue and nerve repair, but there are many limitations and the effect is not good.
    OBJECTIVE: To construct a kind of tissue engineering scaffold material for the regeneration and repair of spinal cord injury.
    METHODS: The dexamethasonemicrospheres were prepared by emulsification-solvent evaporation. The comprehensive scores of encapsulation efficiency, drug-loading rate and yield were taken as the indexes. The effect of dosage of dexamethasone and polylactic acid-glycolic acid copolymer and mass fraction of polyvinyl alcohol on formulation process of dexamethasone sustained-release microsphere was inspected by orthogonal experiment. The characterization of microspheres was observed by scanning electron microscope. The nanofiber scaffold of compound dexamethasone microspheres was prepared by taking collagen protein and polycaprolactone as raw materials using electrospinning technology. The mouse bone marrow mesenchymal stem cells were co-cultured with the scaffold for 3 days. Cell morphology was observed by scanning electron microscope. Composite material was implanted into the defect of spinal cord in rats.
    RESULTS AND CONCLUSION: The optimal preparation process of dexamethasone sustained-release microspheres: dosage of dexamethasone was 10 mg, dosage of poly lactic acid-glycolic acid copolymer was 80%, mass fraction of polyvinyl alcohol was 0.5%. Appearance of dexamethasone microspheres was smooth, with a round surface. The encapsulation efficiency, drug-loading rate and yield of microspheres were (2.26±0.03)%, (83.62±0.21)% and (90.87±2.45)% respectively. The growth of mouse bone marrow mesenchymal stem cells was good on the surface of compound dexamethasone microspheres. There was no immunological reaction between the implant material and host, and the material was degraded gradually with time. These results demonstrate that the compound dexamethasone microsphere scaffold has good biocompatibility, which is a favorable kind of biological scaffold material. 
     

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    Heterogeneous decellularized dermal matrix graft repairs deep burn wounds 
    Pan Nan-fang, Zhuo Jin, Wang Xin
    2016, 20 (3):  408-412.  doi: 10.3969/j.issn.2095-4344.2016.03.019
    Abstract ( 327 )   PDF (980KB) ( 322 )   Save

    BACKGROUND: Patients with deep burn wounds undergoing heterogeneous decellularized dermal matrix graft need to experience a long period of convalescence. During this period, patients are likely to develop pigmentation, scar contracture, looks damage, dysfunction and other complications, so there are relatively high requirements for postoperative functional rehabilitation.
    OBJECTIVE: To discuss the role of functional rehabilitation exercises after the heterogeneous decellularized dermal matrix graft in repair of deep burn wounds.
    METHODS: Totally 72 patients with deep II degree burn were randomly divided into treatment and control groups (n=36/group), and all subjected to heterogeneous decellularized dermal matrix graft treatment. At the day after treatment, patients in the treatment group were subjected to positively postoperative functional rehabilitation exercises; patients in the control group only received psychological assessment and data collection. After 2 months of functional rehabilitation exercises, the assessment results on degree of dermal swelling, pain, serum levels of inflammatory cytokines and quality of life of patients in these two groups were compared.
    RESULTS AND CONCLUSION: There was no significant difference in the degree of dermal swelling of patients between these two groups (P > 0.05). The degree of pain, levels of tumor necrosis factor α and interleukin-6 levels were significantly lower in the treatment group than in the control group (P < 0.05), and the scores of each dimension were significantly higher than in the control group (P < 0.05). These results demonstrate that postoperative functional rehabilitation exercises after the heterogeneous decellularized dermal matrix graft in repair of deep burn wounds can relieve pain, inhibit inflammatory reactions and promote the recovery of the patient’s body function. 

     

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    Different hemodialysis membranes for the treatment of severe pancreatitis
    Zeng Qing-song, Li Jin, Zhu Hai-chao, Xu Yan-qin, Zhu Lin
    2016, 20 (3):  413-417.  doi: 10.3969/j.issn.2095-4344.2016.03.020
    Abstract ( 431 )   PDF (1009KB) ( 329 )   Save

    BACKGROUND: The hemodialysis treatment for severe pancreatitis patients can effectively remove all kinds of toxic substances, but it is unclear whether there are differences in the removal effects of different dialysis membrane materials.
    OBJECTIVE: To explore the clinical application value of hemodialysis membrane materials in the treatment of severe pancreatitis.
    METHODS: Totally 67 patients with severe pancreatitis were enrolled, including 38 males and 29 females, aged 34-81 years, and all underwent continuous bedside hemodialysis within 72 hours of onset. Among them, 32 patients selected polysulfone membrane, and the other 35 patients selected cellulose acetate membrane. Dialysis was done 5 hours once, three times a week. All the patients in these two groups were subjected to stable dialysis for 3 weeks. After 3 weeks, the recovery time required for the levels of serum amylase and white blood cell count in the two groups, treatment efficiency, liver and kidney clinical indicators and levels of inflammatory cytokines were observed and detected.
    RESULTS AND CONCLUSION: There were no significant differences in the recovery time required for serum amylase and white blood cell count, the incidence of adverse reactions and the effective rate of treatment between polysulfone membrane and cellulose acetate membrane groups. The acute physiology and chronic health scores, the levels of serum creatinine, triglycerides, blood amylase, alanine aminotransferase, interleukin-6, C-reactive protein and tumor necrosis factor-α after treatment in these two groups were significantly lower than those before treatment (P < 0.05). The blood O2 pressure was significantly higher than that before treatment (P < 0.05), but there were no significant differences in the above indicators between these two groups. These results demonstrate that the dialysis effects of polysulfone and cellulose acetate membranes are equivalent, both of which can effectively remove the harmful toxins in the body. 

     

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    Optimal dose and mechanism of sodium hyaluronate/carboxymethylcellulose for prevention of postoperative peritoneal adhesions: study protocol for a randomized controlled trial
    Wu Zhi-min, Cui Hong-li,Liu Guo-hui
    2016, 20 (3):  418-422.  doi: 10.3969/j.issn.2095-4344.2016.03.021
    Abstract ( 402 )   PDF (980KB) ( 314 )   Save
    BACKGROUND: Local application of barriers is an effective way to prevent postoperative peritoneal adhesions. In previous experiments, a patented anti-adhesion material, sodium hyaluronate/carboxymethylcellulose, has been prepared. This glue-like polymer material has good biocompatibility, and because of its fluidity and compressibility, it can wriggle with the organs and diffuse in the entire abdominal cavity, and thereby play alubricant role to separate the intestine and peritoneum and reduce tissue adhesion.
    METHODS/DESIGN: A randomized controlled animal experiment has been designed. Animal models of peritoneal adhesion are made in New Zealand rabbits followed by injection of sodium hyaluronate/ carboxymethylcellulose at different concentrations and doses. The optimal concentration and dose of sodium hyaluronate/ carboxymethylcellulose is screened by comparing percentage of peritoneal adhesion between treatment and control groups. Anti-adhesion mechanism of sodium hyaluronate/carboxymethylcellulose is explored through the detection of fibroblast growth factor, endothelial cell growth factor, transforming growth factor β and serum tissue-type plasminogen activator, urokinase-type plasminogen activator and fibrinogen.
    DISCUSSION: This study will be powered to provide experimental evidence for sodium hyaluronate/carboxymethylcellulose in clincial prevention of postoperative peritoneal adhesion, as well as feasible ideas for exploring the anti-adhesion mechanism of sodium hyaluronate/carboxymethylcellulose.
    ETHICAL APPROVAL: This study was approved by the Ethics Committee of the First Hospital of Jilin University. The disposal of animals was in line with the Guideline for the Care and Use of Laboratory Animals formulated by the Ministry of Science and Technology, China in 2006 and the Ethical Issues in Animal Experimentation released in 2009 
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    Construction of tissue-engineered cartilage: characteristics of different scaffolds
    Zheng Yu, Dang Jian-jun, Jin Hong-bin, Cheng Hong-yi, Li Qiang, Qi Lei, Wang Lei, Wang Jian-wu, Xin Rong-chao, Li Hui-min
    2016, 20 (3):  423-429.  doi: 10.3969/j.issn.2095-4344.2016.03.022
    Abstract ( 282 )   PDF (1197KB) ( 316 )   Save

    BACKGROUND: Most scholars believe that the cartilage tissue engineering is a new direction for the treatment of cartilage defects. It has made partial progress in the basic research, and to construct a scaffold is essential in cartilage tissue engineering.
    OBJECTIVE: To systematically review and summarize the application of different tissue-engineered scaffolds in articular cartilage repair.
    METHODS: A computer-based search of CNKI, VIP and PubMed databases was performed for relevant basic research literatures published from January 2005 to January 2015 using the keywords of “tissue engineering, 
    scaffold, cartilage” in Chinese and English, respectively. Meanwhile, references in the retrieved articles were retrieved manually.
    RESULTS AND CONCLUSION: For selection and preparation of tissue-engineered cartilage scaffolds, it is necessary to fully take into account the advantages and disadvantages of natural hydrogel materials, synthetic scaffolds, composite scaffolds, nano-scaffolds, and injectable scaffolds. Currently, there is still no normal transition between all tissue-engineered cartilage scaffolds and the natural cartilage. Therefore, to develop nano-multilayer integrated scaffolds with the calcified cartilage layer is expected to become one of the research focuses of bone and cartilage tissue engineering. 

     

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    Application of intelligent hydrogels in bone regeneration and repair
    Yang Ling, Guan Xiao-yan, Chen Li-ming, Liu Jian-guo
    2016, 20 (3):  430-434.  doi: 10.3969/j.issn.2095-4344.2016.03.023
    Abstract ( 363 )   PDF (891KB) ( 368 )   Save

    BACKGROUND: Intelligent hydrogel as a new material is widely used in biological medicine, tissue engineering, memory element switch, biological enzyme immobilization and other related fields, and exhibits good biological characteristics. Intelligent hydrogels provide a new approach for regeneration and repair of bone and other hard tissues. 
    OBJECTIVE: To summarize the latest developments of intelligent hydrogel in the biological medicine and tissue engineering in order to find out new methods for regeneration and repair of bone and other hard tissues.
    METHODS: A computer-based research of CNKI, PubMed and EBSCO-MEDLINE databases was performed to retrieve relevant literatures about the application of intelligent hydrogel in regeneration and repair of bone and other hard tissues published from 2000 to 2015. The keywords were “hydrogel, bone tissue engineering, bone defect, regeneration, repair” in Chinese and English, respectively.
    RESULTS AND CONCLUSION: Intelligent hydrogels are classified into pH-sensitive, temperature-sensitive, light-sensitive, multiple-sensitive and other sensitive hydrogels. In order to improve the mineralization ability of the hydrogel and construct the three-dimensional polymer scaffold of hydrogel, the main structure of the hydrogel materials can be mixed with various signal factors, thus achieving the multi-utility and multi-function of the material system, which will become the development trend of tissue engineering construction. 

     

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    Silicon-doped nano-hydroxyapatite: solubility, anti-fracture and compressive strengths
    Cheng Yao, Wang Xing-xing, Wang Da-lin
    2016, 20 (3):  435-440.  doi: 10.3969/j.issn.2095-4344.2016.03.024
    Abstract ( 346 )   PDF (1037KB) ( 297 )   Save
    BACKGROUND: Silicon-doped nano-hydroxyapatite has good biocompatibility and bioactivity, and has broad application prospect as a new biological material.
    OBJECTIVE: To summarize the preparation process, principle, method of silicon-doped nano-hydroxyapatite and the effect of different doping methods on the solubility, surface morphology and the in vitro and in vivo biological effects of hydroxyapatite.
    METHODS: The first author searched China National Knowledge Infrastructure (1990-2015), and Medline database (1990-2015) for related articles using the key words of “silicon, nano-hydroxyapatite, biological material,
    biology, tissue engineering, bone repair” in Chinese and English, respectively.
    RESULTS AND CONCLUSION: The preparation methods of silicon-doped nano-hydroxyapatite can be divided into two kinds: liquid phase method and solid phase method. Silicon doping can increase the solubility, anti-fracture and compressive strengths of nano-hydroxyapatite, and promote the osteogenesis of nano-hydroxyapatite, but the effects of different doping methods and specific gravity on the hydroxyapatite are different. Further research screening and optimization are still needed. 
     
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    The application of biodegradable absorbable materials in bone repair
    Hou Li-gang, Yang Jian-yi
    2016, 20 (3):  441-445.  doi: 10.3969/j.issn.2095-4344.2016.03.025
    Abstract ( 482 )   PDF (821KB) ( 363 )   Save

    BACKGROUND: Because there are many inevitable problems in autologous or allogeneic bone grafting for treatment of bone defects, the application of biodegradable absorbable material is the focus of current research.
    OBJECTIVE: To evaluate the biological properties of several kinds of bone repair materials and their influence on bone defect repair after implantation.
    METHODS: PubMed and CNKI databases were retrieved for articles published from 1994 to 2015 by computer. The keywords were “bone defect, biodegradable material, bone graft” in English and Chinese, respectively. 
    RESULTS AND CONCLUSION: Biodegradable absorbable materials mainly include natural polymer materials, synthetic polymer materials and bio-inorganic materials. Biodegradable absorbable materials have good biocompatibility, and can induce new bone ingrowth after implantation to form good osteo-integration. It has shown a clear advantage in bone repair. A variety of materials combined together can promote the repair of bone defects, which is the development trend of alternative materials for bone repair. 

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    Biomaterials in tooth regeneration: application and future
    Yu Yong, Deng Feng, Wu Yan
    2016, 20 (3):  446-450.  doi: 10.3969/j.issn.2095-4344.2016.03.026
    Abstract ( 270 )   PDF (796KB) ( 257 )   Save

    BACKGROUND: The emergence of tissue engineering technology has provided a new possibility for the study of tooth regeneration. The biomaterials used in the research of tooth regeneration have a good implementation prospect, and have achieved some research results, which have become a study hotspot.
    OBJECTIVE: To review the research history, types, characteristics of biomaterials and the research evelopments in the field of tooth regeneration.
    METHODS: The articles about biomaterials and their applications in the tooth regeneration published during 2000 to 2015 were retrieved from CNKI, PubMed and Google Scholar by computer. Typical and creative research achievements were enrolled in result analysis.
    RESULTS AND CONCLUSION: Many research results demonstrate that biomaterials play an irreplaceable role in tooth regeneration, among which the soft biomaterials can be used for wrapping cytoskeleton, whereas the mechanical rigid biomaterials act as the structural substitutes. Therefore, we can use these two kinds of biomaterials together and complementarily. Biomaterials and a variety of dental stem cells all have a good biocompatibility, low cytotoxicity and immunogenicity, which may induce some cells to differentiate toward a particular direction. As more and more research achievements of biomaterials in the field of tissue regeneration have been discovered, how to reduce the costs and realize the clinical applications still need further research.
    中国组织工程研究杂志出版内容重点:生物材料;骨生物材料; 口腔生物材料; 纳米材料; 缓释材料; 材料相容性;组织工程

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    Coronary stenting for myocardial infarction: its developmental trends
    Miao Lei, Liu Pei-liang
    2016, 20 (3):  451-455.  doi: 10.3969/j.issn.2095-4344.2016.03.027
    Abstract ( 314 )   PDF (1024KB) ( 200 )   Save

    BACKGROUND: Coronary stenting can effectively prevent the artery blood vessels against obstruction or stenosis due to fat accumulation and improve cardiac function in patients with myocardial infarction.
    OBJECTIVE: To analyze the clinical trends of different types of coronary stents for myocardial infarction reported 
    from 2004 to 2015 in Medline, CNKI, Wanfang, ClinicalTrials.gov and Chinese Clinical Trial Register.
    METHODS: The relevant articles addressing metal bare stents, drug-eluting stents, and biodegradable stents were retrieved using the keywords of “stent” and “myocardial infarction” in Chinese and English in Medline, CNKI, Wanfang, ClinicalTrials.gov and Chinese Clinical Trial Register followed by statistical analysis. The retrieval time was from 2004 to 2015, including 2004-2007, 2008-2011 and 2012-2015.
    RESULTS AND CONCLUSION: (1) In Medline database, there were 720 clinical studies about coronary stenting for myocardial infarction published from 2004 to 2015. The number of articles addressing drug-eluting stents continued to increase from 2004 to 2007, 2008 to 2011 and 2012 to 2015. The number of articles addressing metal bare stents reached the peak from 2008 to 2011, and then decreased. Biodegradable stents appeared after 2008, and the number of relevant articles was increased gradually. In CNKI and Wanfang databases, the number of metal bare stents for myocardial infarction was at a lower level, while the number of drug-eluting stents was peaked from 2008 to 2011, and at that time, biodegradable stents were rarely reported in China. (2) In ClinicalTrials.gov, the number of clinical trials about metal bare stents for myocardial infarction was relatively low, the number of clinical trials about drug-eluting stents was reduced dramatically from 2012 to 2015, but the number of clinical trials about biodegradable stents for myocardial infarction had a rising trend. 

     

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