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    28 June 2018, Volume 22 Issue 18 Previous Issue    Next Issue
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    Preparation of icariin-poly(lactic acid)/hydroxyapatite composite bone-graft substitutes by supercritical carbon dioxide method
    Zhang Yu-min, Wang Jian-ru, Han Bo, Niu Xiao-jun
    2018, 22 (18):  2789-2794.  doi: 10.3969/j.issn.2095-4344.0786
    Abstract ( 351 )   PDF (807KB) ( 186 )   Save

    BACKGROUND: Our previous findings have shown that poly(lactic acid)/hydroxyapatite (PLA/HA) composite biomaterials prepared by the supercritical carbon dioxide method have good physiochemical properties and biocompatibility. However, the composite materials only have osteoconductivity but no osteoinductivity.

    OBJECTIVE: To prepare icariin-PLA/HA (IC-PLA/HA) composite biomaterials with good osteoconduction and osteoinduction.
    METHODS: The supercritical carbon dioxide method was used to prepare IC-PLA/HA composite biomaterials containing 10-4, 10-5 10-6 mmol/g IC, named as IC-PLA/HA(1 000), IC-PLA/HA(100) and IC-PLA/HA(10). PLA/HA composite material served as controls. Biomechanical properties, porosity, sustained release characteristics were detected, and scanning electron microscope observation was performed, in order to screen out the optimal IC content in the composite materials.
    RESULTS AND CONCLUSION: (1) Compressive strength and elastic modulus of IC-PLA/HA(1 000), IC-PLA/HA(100) and IC-PLA/HA(10) showed no difference from those of PLA/HA. (2) The porosity of all the composite materials was over 75%, and there was still no difference among groups. (3) The IC release from IC-PLA/HA was faster within the first 3 days, and then reduced gradually. However, after 7 days, the IC release plateaued, and the IC release amount from the IC-PLA/HA(100) was close to 10-7 mol/L that had been confirmed to be an effective and safe concentration in the previous experiments. (4) Under the scanning electron microscope, HA and PLA were mixed homogeneously and IC was difficult to be identified. The pore size of the IC-PLA/HA(100) ranged from 50 μm to 150 μm. Overall, the IC-PLA/HA composite biomaterials have good mechanical and sustained-release properties. 
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    Feasibility of balloon dilation with injectable calcium sulfate cement for tibial plateau fractures
    Chen Jin-min, Chen Sui-sheng, Ding Jing, Xia Bao-quan, Luo Xiao-jia, Lu Cheng-hai, Yang Zhen-keng
    2018, 22 (18):  2795-2799.  doi: 10.3969/j.issn.2095-4344.0867
    Abstract ( 312 )   Save

    BACKGROUND: The balloon dilatation technique plays an important role in the correction of kyphosis. A balloon catheter can enlarge the spinal cavity in kyphoplasty followed by injection of bone cement under low pressure to lay a foundation for the stability of the spine.

    OBJECTIVE: To explore the feasibility of balloon dilation with injectable calcium sulfate cement for tibial plateau fractures and to analyze its clinical effect.

    METHODS: Twenty-four upper tibia specimens of the adults were taken to make the Schatzker III collapsed fracture model of the tibial plateau. Then, these specimens were randomized into three groups: the standard group was subjected to poking reduction with autologus bone grafting and screw internal fixation, the bone cement group was inflated with balloon dilatation followed by calcium sulfate cement injection, and the combined group was treated with fixation with cancellous bone screws and balloon dilatation followed by injection of calcium sulfate cement. The general situation of reduction and fixation was observed and the reduction effect was measured.
    RESULTS AND CONCLUSION: (1) Fixation effect in the model: All three models were well reset, and the average displacement of the standard group, the simple bone cement group and the bone cement screw group was (-0.22±0.62), (-0.23±0.67), and (-0.20±0.69) mm, respectively. There was no significant difference in the displacement between the three groups (P > 0.05). (2) Clinical application: One case of Schatzker type II fracture of the left tibial plateau was treated with cancellous bone screw fixation and balloon dilatation followed by injection of calcium sulfate cement. X-ray results showed calcium sulfate cement was visible at 3 postoperative days. At 30 postoperative days, the patient presented with good joint range of motion, and the calcium sulfate was partially absorbed on the X-ray film. At 60 postoperative days, the patient appeared to have no joint extension disorder, and fracture healing and absorption of calcium sulfate as shown by X-rays. To conclude, the balloon dilation with injectable calcium sulfate cement for the treatment of tibial plateau fracture is feasible and has clinical value. 
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    Preparation and property evaluation of a self-setting calcium phosphate cement
    Wang Jian-long, He You, Cheng Zhe, Zheng Zhi, Zhu Kai-di
    2018, 22 (18):  2800-2806.  doi: 10.3969/j.issn.2095-4344.0851
    Abstract ( 372 )   PDF (916KB) ( 181 )   Save

    BACKGROUND: Preliminary studies have found that poly(lactic-co-glycolic acid) (PLGA) can improve the compressive strength and degradability of calcium phosphate cement.

    OBJECTIVE: To prepare a self-setting calcium phosphate cement which has better mechanical properties, biocompatibility and degradability on the basis of the previous findings. 
    METHODS: Beta-tricalcium phosphate (β-TCP), pure calcium phosphate cement (CPC) and PLGA powder were mixed at different mixing ratios for preparation of PLGA/β-TCP/CPC. Setting time, compressive strength, elastic modulus and degradation properties of the composite bone cement were evaluated to screen the optimal level of β-TCP. MC3T3-E1 cells were cultured in CPC extract (control), PLGA/β-TCP/CPC extract (experimental), α-MEM containing 10% fetal bovine serum and 1% penicillin-streptomycin double antibody (negative control), and 6.4% phenol liquid (positive control). MTT method was used to detect cell proliferation at 1, 3, 5 days after culture, and lactate dehydrogenase activity in culture media was detected at 1 and 3 days after culture. MC3T3-E1 cells were seeded on the surface of PLGA/β-TCP/CPC and pure CPC respectively, and were then observed by scanning electron microscopy after 3 days.
    RESULTS AND CONCLUSION: Initial setting time and final setting time among of the composite bone cement were increased with the increasing of β-TCP content, but had no significant difference from those of the CPC (P > 0.05). The compressive strength and elastic modulus of the composite bone cement were higher than those of the CPC, and moreover, the composite bone cement with 20% β-TCP exhibited the highest compressive strength and higher elastic modulus as compared with the other groups. Therefore, PLGA/20% β-TCP/CPC was selected in the cell test. Moreover, the degradation properties of the composite bone cement were also better than those of the CPC. (3) With the growth of culture time, cell absorbance value and lactate dehydrogenase activity were gradually increased in the experimental group, and no difference existed between the experimental group and the negative control group. The cells in the experimental group also grew well. (4) MC3T3-E1 cells grew well and fully extended on the surface of PLGA/β-TCP/CPC, and cell pseudopodia on the material surface were tightly adhered to the material. To conclude, PLGA/20% β-TCP/CPC has better compressive strength, elastic modulus, degradation properties and cytocompatibility relative to the CPC, and moreover, the composite bone cement has no obvious cytotoxicity. 
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    Early vascularization of calcined antler cancellous bone in repairing bone defects
    Peng Hui, Zhang Xue-hui
    2018, 22 (18):  2807-2812.  doi: 10.3969/j.issn.2095-4344.0865
    Abstract ( 355 )   PDF (922KB) ( 415 )   Save

    BACKGROUND: Calcinated antler cancellous bone (CACB) was successfully prepared in the early stage, and was confirmed that it could significantly promote bone defect repair.

    OBJECTIVE: To evaluate the early neovascularization of CACB in a bone defect model.
    METHODS: CACB was prepared by defatted and deproteinized process and combined with calcination after removal of the cortical bone. The surface morphology and phase composition of CACB granules were evaluated by using scanning electron microscope (SEM) and X-ray diffraction spectrum (XRD). Mouse osteoblasts MC3T3-E1 were cultured with CACB for 1 day to assess the cellular affinity by SEM. Models of critical bone defects were prepared on the bilateral mandibles of 16 New Zealand rabbits. CACB was implanted into the defects on the one side, and Bio-Oss® was implanted into the defects on the other side. Nothing was implanted into the defects as blank control. All the rabbit mandibles after 4 and 8 weeks post-surgery were subjected to tissue processing and sectioning. Hematoxylin-eosin, Masson’s trichrome staining and CD31 immunohistochemical method were performed separately on consecutive tissue sections to observe the vascularization and osteogenesis.
    RESULTS AND CONCLUSION: (1) SEM images showed that CACB exhibited a well-interconnected porous structure and was present as regularly prismatic crystals of hydroxyapatite. The XRD spectrograph revealed that the characteristic peaks of CACB corresponded to the peaks of calcinated human cancellous bone, indicating that the hydroxyapatite phase with good crystallinity is the same as that of human bone. (2) The cellular experiment findings showed that CACB could be conducive for attachment and spreading of MC3T3-E1 cells integrated with hydroxyapatite closely. (3) At 4 weeks post-implantation, hematoxylin-eosin staining results showed a lot of newly formed small blood vessels at the periphery of the scaffold of CACB and Bio-Oss®. Masson and CD31 immunohistochemical staining results showed the newly formed collagen fibers and blood vessels around the bone filling materials. Moreover, the ability of vascularization of CACB was more effective than that of Bio-Oss®. (4) At 8 weeks post-implantation, hematoxylin-eosin staining results showed there was a large number of newly formed bones in the bone defects and the remaining scaffold was surrounded by newly formed bones. To conclude, our findings reveal that CACB possesses good vascularization during the bone defect repair, which may have a potentially positive effect on promoting osteogenesis. 
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    Reconstruction of mandibular defects with tissue-engineered bone using 3D bionic printing technology
    Du Guo-qing, Sun Jian, Li Ya-li, Chen Li-qiang, Chen Chen, Deng Nan, Wu Yu-tong, Li Li, Wang Zhi-hao
    2018, 22 (18):  2813-2819.  doi: 10.3969/j.issn.2095-4344.0868
    Abstract ( 403 )   PDF (981KB) ( 211 )   Save

    BACKGROUND: The 3D printed polylactic-co-glycolicacid/nano-hydroxyapatite (PLGA/nHA) scaffold carrying human recombinant bone morphogenetic protein 2 (rhBMP-2)/chitosan (CS) sustained release tissue-engineering bone has good biological activity, mechanical properties, and biological activity of its controlled release rhBMP-2. 

    OBJECTIVE: To investigate the repair of mandibular defects with PLGA/nHA scaffold/rhBMP-2/CS sustained release tissue-engineering bone manufactured using 3D bionic printing technology.
    METHODS: Animal models of bilateral critical mandibular bone defects were established in 27 New Zealand white rabbits, followed by implantation of a 3D-printed PLGA/nHA scaffold/rhBMP-2/CS sustained release tissue-engineering bone on one side (experimental side), and a 3D-printed PLGA/nHA scaffold on the other side (control side). Mandibular specimens were harvested at postoperative days 30, 60 and 90 to carry out cone-beam CT, Micro CT, histological and immunohistochemical examinations.
    RESULTS AND CONCLUSION: The results from micro-CT analysis revealed that the volume of newly formed bone volume and the amount of bone trabeculae on the experimental side were significantly higher than those on the control side at different postoperative time points

    (P < 0.05). The results from cone-beam CT examination showed that at 90 postoperative days, bone density of the bone defect on the experimental side was close to that of the surrounding bone, new bone tissues were full of the original bone defect area, and the trabecular bone arranged regularly, while on the control side, worm-eaten discontinuous low-density osteoid tissues were visible in the bone defect area. Osteogenesis on the experimental side was better than that on the control side. Histological findings demonstrated that on the experimental side, a large amount of mature lamellae were detected in the bone defect area, with well-arranged trabecular bones and abundant capillaries, and moreover, the scaffold material had been completely absorbed. However, low-density, loose-meshed, irregular braided bone tissues with rare capillaries were observed on the control side, and the scaffold material had been mostly absorbed. Immunohistochemical findings indicated that the osteocalcin-dyed area on the experimental side was significantly larger than that of the control side at postoperative 90 days. To conclude, 3D-printed PLGA/nHA scaffold/rhBMP-2/CS sustained release tissue-engineering bone is favorable for the repair and reconstruction of experimental mandibular defects in rabbits.

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    Bouche decompression and implantation of acellular tissue engineered bone with titanium rods for treating early necrosis of the femoral head
    Hu Change-bo, Yang Xin-ming, Wang Rui, Meng Xian-yong
    2018, 22 (18):  2820-2825.  doi: 10.3969/j.issn.2095-4344.0771
    Abstract ( 343 )   PDF (638KB) ( 203 )   Save

    BACKGROUND: For the Ficat II of femoral head necrosis especially with osteoporosis, core decompression with or without acellular tissue engineered bone can result in a higher incidence of femoral head collapse.

    OBJECTIVE: To analyze the clinical effect of core decompression plus implantation of acellular tissue engineered bone with titanium rods in the treatment of early necrosis of the femoral head.
    METHODS: Thirty-five hospitalized patients with early necrosis of the femoral head (40 hips) were enrolled in the study and assigned into a observation group (15 cases with 20 hips, including 10 hips of Ficat I, 10 hips of Ficat II) and a control group (20 cases with 20 hips, including 11 hips of Ficat I, 9 hips of Ficat II). Core decompression plus implantation of acellular tissue engineered bone with titanium rods were conducted in the observation group, while Bouche decompression with implantation of acellular tissue engineered bone was done in the control group. All the patients were followed up for 1 year. Visual analogue scale (VAS) score, Harris hip function score, and progression in necrosis of the femoral head were compared between two groups.
    RESULTS AND CONCLUSION: VAS scores and Harris scores at 1-year follow-up in both groups showed better outcomes (P < 0.001). At the end of 1-year follow-up visit, the Harris score was significantly higher in the observation group than the control group (P < 0.05), while there was no difference in the mean VAS scores between the two groups (P > 0.05). For Ficat II patients, the excellent/good rate in the observation group was higher than that in the control group at the last follow-up (80% vs. 40%, P < 0.05). According to the Ficat staging, the effective rate in the observation group was higher than that in the control group (90% vs. 80%, P < 0.05). During the postoperative 1-year follow-up visit, Ficat I patients presented with better repair of lesions, no degeneration of the hip joint, and no subchondral bone collapse. Overall, it is an effective treatment for early necrosis of the femoral head by core decompression plus implantation of acellular tissue engineered bone with or without titanium rods; however, co-implantation with titanium robs can show better short-term outcomes. 
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    Similarities and differences on complications after cranioplasty with two-dimensional and three-dimensional digital shaping titanium meshes
    Hu Jun-xian, Yuan Yu-ming, Zhao De-ying, Xu Chun-lin, Wu Ya-lan
    2018, 22 (18):  2826-2830.  doi: 10.3969/j.issn.2095-4344.0872
    Abstract ( 631 )   PDF (589KB) ( 162 )   Save

    BACKGROUND: Patients with cranial defects undergoing cranioplasty can develop complications related or unrelated to repair materials.

    OBJECTIVE: To explore the differences and similarities between the two-dimensional and three-dimensional digital shaping titanium meshes for cranioplasty.
    METHODS: The clinical data of 221 patients with skull repair were retrospectively analyzed. Two-dimensional digital shaping titanium mesh was used in 61 cases, and three-dimensional digital shaping titanium mesh used in 160 cases. Postoperative complications related (including exposure of titanium mesh and nail and loosening of titanium nail) or unrelated (including refractory subcutaneous effusion, epilepsy, scalp necrosis, scalp infection, intracranial infection and intracranial hematoma) to repair materials were summarized.
    RESULTS AND CONCLUSION: There were 14 cases of complications (4 related and 10 unrelated) in the two-dimensional digital shaping titanium mesh group, including 2 cases of intractable subcutaneous effusion, 7 cases of epilepsy, 2 cases of titanium mesh and nail exposure, 2 cases of titanium mesh and titanium nail loosening and 1 case of scalp infection. There were 17 cases of complications (0 related and 17 unrelated) in the three-dimensional digital shaping titanium mesh group, including 5 cases of refractory subcutaneous effusion, 9 cases of epilepsy, 1 case of scalp necrosis, 1 case of intracranial infection and 1 case of intracranial hematoma. Significant differences in the complications related to repair materials were found between the two groups (χ2=5.577, P=0.018). Overall findings suggest that the craniotomy with three-dimensional digital shaping titanium mesh can cause fewer material-related complications than that with two-dimensional digital shaping titanium mesh. 
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    Compressive strength of the newly formed tibia after repair with human tooth bone graft
    Fang Ming, Wang Zhi-ying, Cai Lu
    2018, 22 (18):  2831-2835.  doi: 10.3969/j.issn.2095-4344.0873
    Abstract ( 391 )   PDF (815KB) ( 196 )   Save

    BACKGROUND: Human tooth bone graft has been used for bone deficiency in dental implantation, but the strength and quality of newly formed bones with human tooth bone graft are in need of sound investigation.

    OBJECTIVE: To investigate the compressive strength of newly formed rabbit tibia after repair with human tooth bone graft.

    METHODS: Orthodontic teeth, loose molars, bicuspid premolars extracted from patients were taken to prepare human tooth bone grafts. Human tooth bone graft and bovine bone graft were independently placed into the rabbit tibia defects of 5 mm in diameter. Non-injured site served as control group.
    RESULTS AND CONCLUSION: The newly formed rabbit tibia after repair with human tooth bone graft had more intact microstructure and higher maximum compressive strength and stiffness relative to that after repair with bovine bone graft. These findings indicate human tooth bone graft is superior to bovine bone graft in the repair of tibia defects in rabbits. 
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    Preparation and characterization of laser microporous acellular osteochondral scaffolds
    Liu Xue-jian, Liu Shi-chen, Sun Bai-chuan, Zhang Kai-hong, Meng Hao-ye, Wang Yu Huang Shao-dai, Lu Chang-feng, Wang Chong, Yu Wen, Jing Xiao-guang, Zhao Yue, Yang Jian-hua, Peng Jiang
    2018, 22 (18):  2836-2842.  doi: 10.3969/j.issn.2095-4344.0864
    Abstract ( 353 )   PDF (1252KB) ( 218 )   Save

    BACKGROUND: Preparing a scaffold with cartilage derived components and good initial mechanical strength is the direction of tissue engineering cartilage research.

    OBJECTIVE: To prepare porous acellular osteochondral scaffolds, and to explore their mechanical properties and cell compatibility.
    METHODS: Osteochondral bone from the porcine knee joint was taken, and then porous osteochondral scaffolds were made by laser microporation technology. Subsequently, the scaffolds were decellularized chemical methods. Scaffold structure was observed by scanning electron microscopy, and the compression modulus of the scaffolds was determined. Bone marrow mesenchymal stem cells were cultured in L-DMEM containing 10% fetal bovine serum (control group) and cultured in the medium extract of porous acellular osteochondral scaffolds (experimental group), respectively. Cell proliferation was detected by cell counting kit-8 method within 5 days of culture. Bone marrow mesenchymal stem cells were seeded on the porous acellular osteochondral scaffolds, and within 28 days of co-culture, cell growth was observed by hematoxylin-eosin staining and toluidine blue staining.
    RESULTS AND CONCLUSION: (1) Observation under scanning electron microscopy: The porous acellular osteochondral scaffolds had the smooth surface with evenly distributed pores. The pores of the scaffold extended longitudinally into the subchondral bone. (2) Mechanical properties: The average compressive modulus of porous acellular osteochondral scaffolds was 0.77 MPa, which was close to the compression modulus of the normal cartilage (1.15 MPa). (3) Cell counting kit-8 test: There were no differences in cell proliferation between the control and experimental groups at 1, 2, 3, 4 and 5 days of culture. (4) Cell-scaffold co-culture: A large amount of bone marrow mesenchymal stem cells were observed to be adherent to the scaffold after 1 day of culture through hematoxylin-eosin and toluidine blue staining. However, as time went on, a few cells adhered to the pore wall or grew into the pores at 7 and 21 days of culture. There were also some adherent cells but a large amount of cell masses formed in the pores at 28 days of culture. To conclude, the porous acellular osteochondral scaffold has good mechanical properties and cell compatibility. 
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    Effects of Biodentine on proliferation and osteogenesis of MG-63 cells
    Zhai Jiao-yan, Wang Li-na, Liu Qi-cheng, Shi Chun, Niu Wei-dong
    2018, 22 (18):  2843-2848.  doi: 10.3969/j.issn.2095-4344.0776
    Abstract ( 423 )   PDF (752KB) ( 163 )   Save

    BACKGROUND: As a bioactive substance, Biodentine has good compressive strength, bonding strength and less micro-leakage. It has been successfully applied to a variety of clinical indications. However, much less is known about whether Biodentine can promote osteogenesis.

    OBJECTIVE: To explore the effects of Biodentine of different concentrations on proliferation and osteogenesis of MG-63 cells.
    METHODS: The extracts of Biodentine with different concentration gradients (1, 1/2, 1/4, 1/8, 1/16) were prepared. MG-63 cells were cultured in six groups, with the addition of minimum essential medium (control group) and five concentrations of Biodentine extracts. Cell proliferation was detected by cell counting kit-8 assay at 1, 3, 5 and 7 days, and then the best concentration of Biodentine extract was screened. Another MG-63 cells were cultured in minimum essential medium (blank control group) and Biodentine extract of the optimal concentration (experimental group). The expression of osteogenic factor Runx2 mRNA in MG-63 cells was detected by real-time PCR at 1, 3, 5 and 7 days of culture. Then alizarin red staining was used to observe calcified nodules in MG-63 cells at 10 and 14 days of culture.
    RESULTS AND CONCLUSION: (1) At 1 and 3 days of culture, the number of viable cells in different concentration groups was similar to that in the control group (P > 0.05). At 5 days of culture, compared with the control group, the number of viable cells in MG-63 cells was significantly lowered in the 1 concentration group, showed no significant changes in the 1/2, 1/4, 1/8 concentration groups (P > 0.05), and was significantly increased in the 1/16 concentration group (P < 0.05). Therefore, the 1/16 concentration of Biodentine extract was used for further experiment. (2) Runx2 mRNA expression of the experimental group at 1, 3, 5 and 7 days of culture was 1.14, 5.29, 1.08 and 2.11 times that of the control group, respectively (all P < 0.05). (3) At 10 days of culture, both the experimental group and blank control group showed no mineralized nodules; at 14 days of culture, mineralized nodules were observed in the two groups, and larger and darker nodules were seen in the experiment group. To conclude, Biodentine at certain concentrations can promote the proliferation and osteogenic activity of human osteosarcoma cell line MG-63. 
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    In vitro antibacterial effect of benzalkonium chloride on five common oral pathogens
    Dai Jing, Chen Yan-bin, Chen Shan, Ren Jing, Li Kun-man, Yang Jun-ying
    2018, 22 (18):  2849-2854.  doi: 10.3969/j.issn.2095-4344.0703
    Abstract ( 504 )   PDF (1450KB) ( 224 )   Save

    BACKGROUND: Benzalkonium chloride has been used in dental restorative materials to enhance the long-lasting antibacterial properties of materials.

    OBJECTIVE: To evaluate the antibacterial activity of benzalkonium chloride on oral common pathogenic bacteria in vitro.
    METHODS: The agar diffusion method was used to determine the inhibitory effects of antibacterial agents, 0.1% benzalkonium chloride, 3% H2O2 and 5.25% sodium hypochlorite, on five kind of oral pathogens, Porphyromonas gingivalis (P.g), Prevotella intermedia (P.i), Actinobacillus actionmycemcomitans (A.a), Streptococcus mutans (S.m) and Enterococcus faecalis (E.f). The tube dilution method was used to detect the minimal inhibitory concentration of benzalkonium chloride against the five bacteria mentioned above.
    RESULTS AND CONCLUSION: The antibacterial effect of 0.1% benzalkonium chloride on P.g was not significantly different from that of 3% hydrogen peroxide (P > 0.05), while 0.1% benzalkonium chloride showed better effect on P.i than 3% hydrogen peroxide (P < 0.05). On P.g and P.i, the antibacterial effect of 0.1% benzalkonium chloride was worse than that of 5.25% sodium hypochloritethe (P < 0.05). The antibacterial effect of 0.1% benzalkonium chloride on A.a and S.m was better than that of 3% hydrogen peroxide (P < 0.05), and similar to that of 5.25% sodium hypochlorite (P > 0.05). The antibacterial effect of 0.1% benzalkonium chloride on E.f was better than that of 3% hydrogen peroxide (P < 0.05), but worse than that of 5.25% sodium hypochlorite (P < 0.05). The minimal inhibitory concentration of benzalkonium chloride to P.g, P.i, A.a, S.m, E.f was 16, 2, 4, 2, 4 mg/L, respectively. To conclude, 0.1% benzalkonium chloride has strong antibacterial effects on P.g, P.i, A.a, S.m and E.f
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    Prognostic evaluation of the labial bone plate after anterior maxillary repair with immediate implant combined with immediate restoration
    Li Shao-bing, Ni Jia, Zhang Xue-yang, Huang Yan-hong, Rong Ming-deng, Lu Hai-bin
    2018, 22 (18):  2855-2859.  doi: 10.3969/j.issn.2095-4344.0878
    Abstract ( 336 )   PDF (656KB) ( 174 )   Save

    BACKGROUND: The immediate implantation in the anterior maxillary region is in a high risk of aesthetic complications.

    OBJECTIVE: To assess the prognosis of the labial bone plate after anterior maxillary repair with immediate implant combined with immediate restoration.
    METHODS: Thirty-two patients with single failed tooth in the anterior maxillary region were subjected to implantation of ZIMMER implants immediately after minimally invasive extraction. Good primary stability was achieved and immediate restoration was carried out. Final restoration was finished after 6-12 months of osteosynthesis and gingival shaping. The loading situation of the labial bone plate was recorded at 6 months post operation.

    RESULTS AND CONCLUSION: Final restoration was finished with normal loading in all the patients. No bleeding and swelling of the gingiva was recorded. The horizontal absorption of the labial bone plate at the upper margin, 5 mm and 10 mm below the upper margin was (-2.12±0.05), (-1.54±0.04), and (-1.01±0.06) mm, respectively. Therefore, absorption of the labial bone plate with varying degrees exists after anterior maxillary repair with immediate implant combined with immediate restoration.

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    Frictional resistance of archwires with various ligations in alignment phase
    Zhang Ming-can, Ma Xiao-zhou, Wu Jie, Zhao Wei, Sun Hai-yuan, Zhao Yi-song
    2018, 22 (18):  2860-2865.  doi: 10.3969/j.issn.2095-4344.0884
    Abstract ( 395 )   PDF (709KB) ( 217 )   Save

    BACKGROUND: Clinical ligation of traditional brackets by stainless steel ligature wires has greater randomness among doctors, and previous studies have mainly concerned on brackets and wires. There are less studies on the differential frictional force due to tight or loose ligation, and moreover, how to define tight ligation or loose ligation is rarely reported.

    OBJECTIVE: To compare the frictional force of different archwires in multiple brackets with various ligations.
    METHODS: A plaster model with moderate crowded malocclusion was randomly selected, and copied by 3D digital scanning technologies and Objet30 OrthoDesk3D printing technologies. Then, the models were bonded with Damon Clear brackets, Damon 3MX brackets, 3M traditional MBT brackets and Habit monocrystal brackets. Frictional forces of different brackets on models combined with two types of low frictional NiTi archwires which were 0.30 mm (0.012 inch) and 0.36 mm (0.014 inch) were measured by microcomputer servo dynamometer. Traditional brackets were ligatured by tight ligation and loose ligation, respectively.

    RESULTS AND CONCLUSION: (1) When low-friction NiTi archwires of 0.30 mm were used, significant differences in the frictional force were found between different brackets with various ligations except for Damon Clear bracket versus 3M bracket with loose ligation as well as Damon Clear bracket versus Damon 3MX bracket (P < 0.05). (2) When low-friction NiTi archwires of 0.36 mm were used, similarity in the frictional force was found between 3M bracket with loose ligation, Damon Clear bracket and Damon 3MX bracket, while there were no significant differences between 3M bracket with loose ligation and Damon 3MX, between 3M bracket with tight ligation and Habit bracket with loose ligation, as well as between Damon Clear bracket and 3M bracket with loose ligation (P > 0.05). Comparing two kinds of archwires, the friction force showed no statistical difference between Damon Clear bracket and 3M bracket with loose and tight ligation (P > 0.05), but a statistical difference was found between Damon 3MX bracket and Habit bracket (P < 0.001), whatever two conventional brackets with tight ligation or loose ligation. To conclude, conventional MBT bracket with loose ligation can reduce frictional force as similar as self-ligating bracket in the alignment phase, and the reduction in the friction force is impacted by archwire size and bracket material.

    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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    The corrosion resistance of rotary nickel titanium root canal files
    Hu Xin, Wu Hui, Wang Lei, Zhang Qian, Ning Jia, Wu Wen-meng
    2018, 22 (18):  2866-2871.  doi: 10.3969/j.issn.2095-4344.0765
    Abstract ( 339 )   PDF (635KB) ( 185 )   Save

    BACKGROUND: A nickel titanium root canal file is the major instrument in root canal therapy, and its corrosion resistance is an important factor influencing its normal use. Therefore, it is of great clinicals ignificance to study the corrosion resistance of nickel titanium root canal files.

    OBJECTIVE: To assess the corrosion resistance and anti-fatigue breaking ability of M3 nickel titanium root canal files after rotating in NaOCl and autoclave sterilization.
    METHODS: Seventy-five M3 nickel titanium files were randomized into five groups (n=15 per group): A group, without any treatment, as a blank control; B group, rotating in 5.25% NaOCl for 10 minutes, repeated five times; C group, autoclave sterilization, repeated five times; D group, rotating in 5.25% NaOCl for 10 minutes, followed by autoclave sterilization, repeated five times; E group, rotating in 5.25% NaOCl 10 minutes, followed by autoclave sterilization, repeated 10 times. The anti-fatigue breaking ability and corrosion resistance (polarization resistance, electrochemical impedance and polarization curve) of M3 nickel titanium files after rotating in 5.25% NaOCl or/and autoclave sterilization were observed.
    RESULTS AND CONCLUSION: (1) Anti-fatigue fracture ability: there was no difference among groups in rotation number before the breakage. (2) Polarization resistance value: group E had the highest polarization resistance value which showed two orders of magnitude higher than that of group A; compared with group A, groups B and D showed a little increase in the polarization resistance value; and the polarization resistance values in groups A and C were of the same order of magnitude. (3) Electrochemical impedance: group E had the highest electrochemical impedance; compared with group A, the electrochemical impedance of groups B and D was improved; and the electrochemical impedance of groups C and A was of the same order of magnitude. (4) The polarization curve: all groups showed certain passivation characteristics. The passivation zone was unapparent in group A, became obvious in group E. There were similar polarization curves in the groups C and D. Group B showed relatively positive corrosion potential. In summary, both 5.25% sodium hypochlorite solution and autoclave sterilization have no influence on the anti-fatigue breaking ability of M3 nickel titanium files, but the combined use can enhance the corrosion resistance ability of M3 nickel titanium files. 
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    An in vivo and in vitro study on the effect of tooth liquid polish sealant on the bond strength of orthodontic brackets
    Lin Bao-shan, Li Ting
    2018, 22 (18):  2872-2876.  doi: 10.3969/j.issn.2095-4344.0862
    Abstract ( 349 )   PDF (567KB) ( 159 )   Save

    BACKGROUND: BISCOVER LV is a low-viscosity, ligh-cured resin formulation that can be directly coated on the tooth enamel surface for resin polishing inside and outside the mouth or bracket bonding for enamel demineralization.

    OBJECTIVE: To evaluate the effect of tooth liquid polish sealant on the shear bond strength of orthodontic brackets and the failure rate of bracket bonding.
    METHODS: (1) In vivo test: 30 teenager patients under orthodontic treatment were randomly selected. BISCOVER LV was used to deal with the upper and lower dentitions on the left side, and then the brackets were bonded by a light-cured resin adhesive (Transbond XT). The upper and lower dentitions on the right side were directly bonded with the brackets by Transbond XT. After 1 month, the failure rate of bracket bonding was detected in each patient. (2) In vitro test: 60 extracted orthodontic teeth were selected and randomized into two groups: BISCOVER LV group and non-BISCOVER LV group. The following procedures in the in vitro test were the same as those in the in vivo test. Two groups of specimens were thereafter soaked in the artificial saliva, the shear bond strength of the brackets was tested, and then the adhesive remnant index was recorded.
    RESULTS AND CONCLUSION: (1) In the in vivo test, there was no significant difference in the failure rate of bracket bonding between two clinical groups (11.43% vs. 9.64%; P > 0.05). (2) In the in vitro test, there was no significant difference in the shear bond strength of the brackets[(9.24±2.06) MPa vs. (9.59±2.24) MPa; P > 0.05] as well as in the adhesive remnant index record between the two groups. Therefore, we can make the conclusion that the use of tooth liquid polish sealant for prevention of enamel demineralization has no effect on the bond strength of brackets. 
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    Stress analysis of two kinds of adhesives used in a three-dimensional finite element model of mesio-occluso-distal cavity gold alloy inlay
    Hu Yang, Feng Ming, Zhu Jun
    2018, 22 (18):  2877-2883.  doi: 10.3969/j.issn.2095-4344.0876
    Abstract ( 276 )   PDF (959KB) ( 104 )   Save

    BACKGROUND: Gold alloy inlays have a long history of application in the repair of posterior dental defects. As the gold standard for inlay repair, its excellent mechanical properties and biocompatibility have long been recognized. However, there is no consensus on the design of gold alloy inlays, selection of adhesives, stress analysis of the bonding interface, and design and assessment of resistance and retention forms of the remaining tooth tissues. Further investigation is beneficial to increase the long-term success in gold alloy inlays.

    OBJECTIVE: To establish a three-dimensional finite element model of mesio-occluso-distal cavity (MOD) gold inlay of the third molar in the right mandible, and after the use of 3M RelyX Unicem and vario-link resin adhesive to bond the gold alloy inlay, to explore the stress distribution and characteristics of bonding interface and dental tissues with different cavity depth.
    METHODS: Micro-CT scanning, Mimics, Goemagic Studio, NX 10.0 and other software were used to establish a three-dimensional finite element model of MOD gold inlay with different cavity depths and adhesives. Profiles for different models are as follows: Model A: cavity depth, 1 mm; cavity width, 3 mm; adhesive, 3M RelyX Unicem resin adhesive. Model B: cavity depth, 2 mm; cavity width, 3 mm; adhesive, 3M RecessX Unicem resin adhesive. Model C: cavity depth, 4 mm; cavity width, 3 mm; adhesive, 3M RelyX Unicem resin adhesive. Model D: cavity depth, 1 mm; cavity width, 3 mm; adhesive, vario-link resin adhesive. Model E: cavity depth, 2 mm; cavity width, 3 mm; adhesive, vario-link resin adhesive. Model F: cavity depth, 4 mm; cavity width, 3 mm; adhesive, vario-link resin adhesive. With the grid of ANSYS Workbench software, the stress distribution of models at 10 N•mm torque under lingual 45° 175 N and lingual 90° 600 N were analyzed.
    RESULTS AND CONCLUSION: Minimal equivalent stress of the tooth root was found in the model with cavity depth of 2 mm under lingual 45° 175 N, which was suitable for gold alloy inlays and vario-link adhesive repair. Under lingual 90° 600 N, the equivalent stress of the tooth root was higher in model F than model C; the maximum root stress in model A was higher than that in model A; the equivalent stress of the tooth root was higher in vario-link models than 3M RelyX Unicem models. When the cavity depth was equal to 4 mm, a higher destructive stress of the tooth root produced on the vario-link bonding interface. In each model, the stress mainly concentrated on the root bifurcation zone, roof of the medullary cavity, gingival wall, and the 1/3 of the mesial or distal root. These findings suggest that the size and area of stress concentration are different under different cavity depth, adhesives and loading conditions. The shallow (< 1 mm) or deep (> 4mm) MOD cavity design should be avoided. Both 3M RelyX Unicem and vario-link are adhesives for gold alloy inlay. However, further clinical trials are needed to verify the results of three-dimensional finite element models. 
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    Effects of high-flux hemodialysis on nutrition status and prevalence of periodontitis in maintenance hemodialysis patients
    Gong Chao, Xu Yan
    2018, 22 (18):  2884-2889.  doi: 10.3969/j.issn.2095-4344.0866
    Abstract ( 521 )   PDF (643KB) ( 158 )   Save

    BACKGROUND: Studies have shown that the prevalence of periodontitis is significantly higher in maintenance hemodialysis patients than the normal population. Therefore, how to improve the malnutrition and periodontal status of MHD patients has been an issue of concerns.

    OBJECTIVE: To explore the effects of high-flux hemodialysis on nutritional status, micro-inflammatory state and prevalence of periodontitis in maintenance hemodialysis patients.
    METHODS: Fifty patients with end-stage renal disease were divided into two groups for maintenance hemodialysis. The experimental group (n=25) was subjected to high-flux hemodialysis (ultrafiltration coefficient 59 mL/(h•mm Hg), effective surface area 1.8 m2). In the control group (n=25), low-flux hemodialysis (ultrafiltration coefficient 12 mL/(h•mm Hg), effective surface area 1.4 m2) was performed. Polysulfone membrane dialyzer was used in both groups. Serological indicators and scores on modified quantitative subjective global assessment (MQSGA) (including changes in body weight, diet, gastrointestinal symptoms, activity capacity, complications, degree of fat consumption and muscle consumption) to assess the nutritional status were tested in each group before dialysis and at 1 year of dialysis. Periodontal status of the two groups was examined at 1 year of dialysis.

    RESULTS AND CONCLUSION: (1) Nutritional status MQSGA score: compared with pre-dialysis, the activity ability and muscle consumption scores of the experimental group was significantly reduced at 1 year of dialysis (P < 0.05), and the other indicators did not change significantly. In the control group, there were no significant changes in all the indicators at 1 year after dialysis. The scores of body weight, activity capacity and muscle consumption in the experimental group were significantly lower than those in the control group at 1 year of dialysis (P < 0.05).   (2) Serological indicators: Compared with the pre-dialysis, the hemoglobin, albumin and prealbumin levels in the experimental group were significantly increased at 1 year of dialysis (P < 0.05), while high-sensitivity C-reactive protein, triglycerides, total cholesterol, intact parathyroid hormone, serum β2-microglobulin, serum creatinine and urea nitrogen levels decreased (P < 0.05). The control group also had insignificant changes in the above indexes at 1 year of dialysis. The hemoglobin, albumin and prealbumin levels in the experimental group were significantly higher than those in the control group at 1 year of dialysis (P < 0.05), and the levels of high-sensitivity C-reactive protein, triglyceride, total cholesterol, intact parathyroid hormone, serum β2-microglobulin was lower than those in the control group (P < 0.05).      (3) Periodontal status: The prevalence of periodontitis was lower in the experimental group than in the control group (P < 0.05). These findings reveal that high-flux hemodialysis can improve the nutritional status and micro-inflammation state of maintenance hemodialysis patients, and it also effectively reduces the prevalence of periodontitis.

    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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    Rapamycin-eluting stents for unprotected left main coronary artery stenosis in coronary atherosclerosis in the older adults: study protocol for a prospective, non-randomized, controlled trial and preliminary results
    Chen Wei, Fang Zhi-cheng, Zheng Xiang, Liu Bo-yi, Zhao Ji-xian, Liao Ying-ying
    2018, 22 (18):  2890-2895.  doi: 10.3969/j.issn.2095-4344.0887
    Abstract ( 325 )   PDF (661KB) ( 145 )   Save

    BACKGROUND: Coronary artery bypass grafting (CABG) is the gold standard therapy for unprotected left main coronary artery (ULMCA) stenosis in coronary atherosclerosis. However, the treatment of ULMCA stenosis using drug-eluting stents has recently been reported to lead to a relatively low incidence of cardiovascular events.Thus,drug-eluting stents are a potential surrogate for CABG,and could become the new gold standard treatment for ULMCA stenosis; however, this issue remains controversial.

    OBJECTIVE: To explore the safety and efficacy of CABG versus rapamycin-eluting stents for ULMCA stenosis in older adult patients with degenerative coronary atherosclerosis.
    METHODS: The proposed prospective, non-randomized, controlled trial will include 224 older adult patients with degenerative coronary atherosclerosis with ULMCA stenosis being treated at the Department of Cardiology at Taihe Hospital and Renmin Hospital of Shiyan, China. Patients will be divided into two groups in accordance with each patient’s treatment choice and indications (n=112/group): the stent group will receive rapamycin-eluting stents, while the CABG group will undergo CABG.All patients will be followed up at 9, 12, 24, and 36 months postoperatively. The primary outcome measure will be the rate of repeat revascularizations in the target lesion at 36 months postoperatively.The secondary outcome measures will be the rates of repeat revascularizations in the target lesion at 9, 12, and 24 months postoperatively, the rate of restenosis, mortality, causes of death, and survival at 9, 12, 24, and 36 months postoperatively, and the angiographic appearance of the diseased vessels preoperatively and at 9, 12, 24, and 36 months postoperatively. The safety indicator will be the incidence of major adverse cardiac and cerebrovascular events at 9, 12, 24, and 36 months postoperatively. Eighty-six older adult patients with degenerative coronary atherosclerosis who underwent treatment of ULMCA stenosis between January 2016 and December 2017 were included in a pilot study. Pilot study results showed that the stent group (n=48) had a significantly reduced waiting time for surgery, hospitalization time, and rate of complete revascularizations in the target lesion compared with the CABG group (n=38) (P < 0.05). At 6 months postoperatively, there were no significant differences between the two groups in mortality, and incidences of myocardial infarction, repeat revascularizations in the target lesion, and cardiovascular events. The trial was approved by the Ethics Committee of Taihe Hospital (approval No. TH005X) in July 2017 and by the Ethics Committee of Renmin Hospital of Shiyan (approval No. RM011X) in July 2017. All the patients will provide written informed consent with the premise of fully understanding the treatment plan. The study protocol will follow the relevant laws and regulations of the Declaration of Helsinki and relevant hospital’s ethical principles. Design of the trial was completed in January 2018. Recruitment will be initiated in August 2018 and it is expected to be completed in August 2019. Data analysis will be conducted in October 2022 and the trial will be completed in December 2022. The results of the study will be disseminated through presentations at scientific meetings and/or in peer-reviewed publications. The trial has been registered with the Chinese Clinical Trial Registry (registration No. ChiCTR1800016413) and the version number is 1.0

    DISCUSSION: The results of this study will indicate the medium- and long-term efficacy and safety of rapamycin-eluting stents versus CABG in older adult patients with ULMCA stenosis, and then identify which of these two treatments has better prognosis, thereby screening out the optimal strategy for treating ULMCA.

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    Ligustrazine nano-spray against postoperative abdominal adhesion
    Lian Zi-yu, Yang Li-li, Bian Yao-yao, Wang Ya-jie, Ma Yan-ting, Wang Ye-tong, Tang Sheng-jin, Zeng Li, Li Wen-lin
    2018, 22 (18):  2896-2902.  doi: 10.3969/j.issn.2095-4344.0875
    Abstract ( 316 )   PDF (947KB) ( 160 )   Save

    BACKGROUND: Oxidative stress is one of the important mechanisms of postoperative abdominal adhesion. The nuclear factor-E2-related factor 2 (Nrf2)-antioxidant response element (ARE) signal pathway is an important endogenous anti-oxidation stress pathway. Our previous study found that ligustrazine nano-spray can inhibit the formation of postoperative abdominal adhesion in rats, and moreover, ligustrazine has an anti-oxidation effect.

    OBJECTIVE: To observe the effect of ligustrazine nano-spray on the expression of mRNAs and proteins related to the Nrf2-ARE signal pathway in rats with abdominal adhesion, and to investigate the mechanism by which ligustrazine nano-spray inhibits abdominal adhesion via regulating the Nrf2-ARE signal pathway.
    METHODS: Sprague-Dawley rats were randomly divided into sham group, model group, ligustrazine group and sodium hyaluronate group. In the sham group, only laparotomy was performed without modeling. In the model group, an abdominal adhesion model was created but no drug was used. In the ligustrazine group, ligustrazine nano-spray was used on the wound before incision suturing. In the sodium hyaluronate group, sodium hyaluronate was applied on the wound before incision suturing.
    RESULTS AND CONCLUSION: Compared with the model group, ligustrazine nano-spray reduced the levels of reactive oxygen species, tissue inhibitor of matrix metalloproteinase 1, but increased the level of matrix metalloproteinase 9 in the rat serum. The expression of Nrf2 and HO-1 mRNA and proteins was also up-regulated in the ligustrazine group relative to the model group. Therefore, ligustrazine nano-sprays can inhibit abdominal adhesions in rats, and its mechanism may be related to the regulation of Nrf2 and heme oxygenase 1 mRNA and proteins expression and the activation of Nrf2-ARE signaling pathway. 
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    Effect of nano-scaled surface roughness on the biological properties of hydroxyapatite ceramics
    Liu Dan, Wu Yong-hao, Li Xiang-feng, Zhu Xiang-dong, Zhang Xing-dong
    2018, 22 (18):  2903-2909.  doi: 10.3969/j.issn.2095-4344.0883
    Abstract ( 437 )   PDF (1024KB) ( 349 )   Save

    BACKGROUND: Hydroxyapatite ceramic is one of the bioactive ceramics commonly used in clinic. Accurate regulation of the surface microstructure of hydroxyapatite ceramics is favorable for improving its biological

    performance, which is needed to be investigated thoroughly.
    OBJECTIVE: To investigate the effect of surface roughness on the wettability and protein adsorption ability of hydroxyapatite ceramic as well as mesenchymal stem cell proliferation on its surface.
    METHODS: Hydroxyapatite powders were synthesized by chemical precipitation method. Hydroxyapatite ceramics were produced by cold isostatic pressing of the powders and then high-temperature sintering of the obtained green compacts. After the different grinding and polishing processes, the hydroxyapatite ceramics with three distinct surface roughness were fabricated. The phase composition, microstructure, surface roughness and water contact angle of the hydroxyapatite ceramics were evaluated. Bovine serum albumin was used as the protein model to study the effect of surface roughness on protein adsorption. The in vitro cell culture was carried out to investigate the effect of surface roughness of hydroxyapatite ceramics on the growth and proliferation of rat bone marrow mesenchymal stem cells.
    RESULTS AND CONCLUSION: The hydroxyapatite ceramics with no surface treatment had higher surface roughness, presenting with marked undulating surface; the hydroxyapatite ceramics with surface grinding had a reduction in the surface roughness, but still had an undulating surface; and the hydroxyapatite ceramics with polishing treatment had a smooth surface. The surface roughness of the three hydroxyapatite ceramics with different surface treatment as mentioned above was 448.4, 229.9 and 18.6 nm, respectively, and there was a significant difference between them. The results of contact angle tests indicated that water contact angle of the hydroxyapatite ceramic was influenced by its surface roughness. Lower surface roughness meant larger contact angle, leading to the decreased hydrophilicity of the hydroxyapatite ceramics. The protein adsorption experiment showed that the hydroxyapatite ceramics were favorable for bovine serum albumin adsorption, and the amount of the adsorbed bovine serum albumin was dependent on the surface roughness of the ceramic as well as the initial concentration of the protein solution. The hydroxyapatite ceramics with higher surface roughness would absorb more bovine serum albumin, and the bovine serum albumin adsorption increased with the increasing initial concentration of the protein solution. The in vitro cell culture confirmed that surface roughness impacted the proliferation of rat bone marrow mesenchymal stem cells. Although the good attachment and growth of bone marrow mesenchymal stem cells were observed on the three hydroxyapatite ceramics, faster proliferation of mesenchymal stem cells occurred on the hydroxyapatite ceramics with lower and nano-scaled surface roughness was observed. Therefore, the surface roughness of hydroxyapatite ceramics exerts great effects on hydrophobicity, protein adsorption, and cell proliferation and growth. 
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    In vitro evaluation of silver ion implantation into titanium dioxide coating against Staphylococcus aureus
    Song Hui, He Tao, Li Gen, Dong Yu-qi, Zhang Chao
    2018, 22 (18):  2910-2914.  doi: 10.3969/j.issn.2095-4344.0854
    Abstract ( 340 )   PDF (732KB) ( 172 )   Save

    BACKGROUND: It is a challenge to seek for ideal anti-bacterial surface modification by which silver ions can have sustained and durable release.

    OBJECTIVE: To investigate the in vitro characteristics and effect of titanium dioxide coating with silver ion injection against Staphylococcus aureus.

    METHODS: There were four groups in the study: control group (pure titanium), titanium oxide coating group, low silver ion group (titanium oxide coating+30 minutes injection of silver ions), and high silver ion group (titanium oxide coating+60 minutes injection of silver ions). Characteristics of the implanted material in each group were observed using scanning electron microscope. Antibacterial efficacy for Staphylococcus aureus was assessed through bacterial instillation method, antibacterial ring test, and microbial growth curve.

    RESULTS AND CONCLUSION: Silver ions could be loaded onto the surface of the titanium dioxide coating through the silver ion implantation. Moreover, the number of silver ions on the coating surface and the antibacterial ability of the modified coating were both increased with the extension of injection time. Therefore, the silver ion implantation technology is beneficial to prepare inorganic antibacterial materials with strong and long-lasting antibacterial ability.

    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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    Simultaneous determination of 18 different amino acids in in vitro fertilization medium by ultra-high performance liquid chromatography–tandem mass-spectrometry
    Huang Yuan-li, Ke Lin-nan, Li Chang-kun, Wang Chun-ren
    2018, 22 (18):  2915-2920.  doi: 10.3969/j.issn.2095-4344.0860
    Abstract ( 304 )   PDF (776KB) ( 245 )   Save

    BACKGROUND: At present, in the quality control file or technical standards of in vitro fertilization medium, indicators for component contents and detection methods have not yet been defined. To ensure the safety and effectiveness of these products, we should try to establish and improve the quality standards.

    OBJECTIVE: To establish a method for simultaneously testing 18 kinds of amino acids by ultra-high performance liquid chromatography–tandem mass-spectrometry (UHPLC-MSMS), and to analyze the difference in the content of different amino acids in the medium for different uses.
    METHODS: Using the UHPLC-MSMS, we detected the indicator components of 18 different amino acids in the in vitro fertilization medium. These amino acids included glycine, leucine, methionine, tyrosine, histidine, threonine, alanine, isoleucine, tryptophan, cystine, lysine, aspartic acid, valine, phenylalanine, valine, serine, glutamic acid, arginine. The UHPLC separation was performed on a SUPELCO Discovery HS F5-3 column (15 cm×2.1 mm, 3 μm) in a gradient elute mode with acetonitrile and water (both containing 0.1% formic acid) as the mobile phase at a flow rate of 0.35 mL/min. The column temperature was 40 ℃. MS detection was performed with multiple-reaction monitoring mode using negative electro spray ionization.

    RESULTS AND CONCLUSION: The linearity was achieved in the range of 0.25-12.5 mmol/L for the 18 different amino acids. The average recovery rate of these amino acids ranged 86.3% to 125.3%. The relative standard deviation of the precision experiment and the repeatability experiment was less than 4.7%. These findings indicate that this is a sensitive, rapid, accurate, and specific method that can be used for the quality control of in vitro fertilization medium.

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    Evaluation methodology of cellular uptake of magnetic nanoparticles
    Wang Run-sheng, Liu Yi-hao, Mao Ke-ya
    2018, 22 (18):  2921-2926.  doi: 10.3969/j.issn.2095-4344.0766
    Abstract ( 495 )   PDF (859KB) ( 320 )   Save

    BACKGROUND: Magnetic nanoparticles have attracted tremendous attention for their diverse biomedical applications involving tumor hyperthermia, drug controlled release and magnetic resonance angiography. The interaction between biomaterials and cells is the major part in the in vitro study, and the evaluation of cellular

    uptake of magnetic nanoparticles is indispensable for tumor hyperthermia and drug delivery.
    OBJECTIVE: To review the progress of evaluation methodology of cellular uptake of magnetic nanoparticles.
    METHODS: The articles about magnetic nanoparticles and cellular uptake were retrieved from PubMed, SCI and Embase databases published during January 2010 to June 2017 by the first author using computer. The Mesh terms were “magnetic nanoparticles”, and the key words were “cellular uptake”, “internalization” or “endocytosis”. The logical operator between them was “AND”.

    RESULTS AND CONCLUSION: Qualitative quantitative assessment methods for cellular uptake of magnetic nanoparticles include Prussian blue staining, fluorescence microscopy, confocal microscopy,transmission electron microscopy. Quantitative assessment methods for cellular uptake of magnetic nanoparticles include inductively coupled plasma, magnetization measurements, colorimetry of Prussian blue staining. The development direction of the evaluation methodology is from qualitative to quantitative. As each method has its own merits and demerits, we should choose the right evaluation method based on the function and application of magnetic nanoparticles and then supply the right experimental basis for the biomedical application of magnetite nanoparticles.

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    Effect of hyaluronic acid and its derivatives on osteoblast function: molecular mechanisms and clinical values
    Di Jia-wei, Li Xiang, Xie Rui-min, Wang Yong-ping
    2018, 22 (18):  2927-2932.  doi: 10.3969/j.issn.2095-4344.0749
    Abstract ( 463 )   PDF (717KB) ( 201 )   Save

    BACKGROUND: Hyaluronic acid, as an important part of extracellular matrix, plays an important role in various biological processes. Hyaluronic acid has good biocompatibility, biodegradability and non-immunogenicity. It is an ideal raw material to prepare a variety of materials with different morphologies, hardness, and bioactivities.

    OBJECTIVE: To analyze the effect of hyaluronic acid and its derivatives on osteoblast growth and differentiation.
    METHODS: The CNKI and PubMed databases were searched with the key words of “hyaluronic acid, osteoblast” in Chinese and English, respectively. Initially 81 articles were retrieved, and only 34 eligible articles were included in result analysis after removal of unrelated or duplicate literature.

    RESULTS AND CONCLUSION: Hyaluronic acid has been widely used in the studies on cell adhesion and migration, angiogenesis and morphogenesis, wound healing, inflammation and cancer metastasis. Hyaluronic acid and its related biomaterials have a positive effect on osteoblast growth and differentiation. Hyaluronic acid and its related biomaterials can serve as molecular chaperones to protect the encapsulated growth factors and drugs, and release them in specific sites to achieve the regulation of desired cellular functions. As a potential new clinical biomaterial, it can be used for the development of tissue engineering scaffolds, drug sustained-release media, and growth factor targeting vectors. As the modern medicine is focusing on the “interdisciplinary”, hyaluronic acid hydrogel materials that are more intelligent and personalized will be the research focus of future medical materials.

     

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    Zoledronic acid promotes dental implant osseointegration in osteoporosis
    Huang Xiao-lin, Yao Chao, Cheng Yu-ting, Li Fang, Wang Yong, Liao Jian
    2018, 22 (18):  2933-2938.  doi: 10.3969/j.issn.2095-4344.0855
    Abstract ( 378 )   PDF (685KB) ( 161 )   Save

    BACKGROUND: Zoledronic acid can effectively enhance dental implant osseointegration, but it can also impair soft tissue and blood supply around the implant, eventually leading to bisphosphonate-associated osteonecrosis of the jaw. Therefore, it is a problem highly valued in implant restorations.

    OBJECTIVE: To review the application of zoledronic acid in the dental implantation after osteoporosis.
    METHODS: The first author searched PubMed and CNKI using computer for relevant articles concerning the potential mechanism by which zoledronic acid promotes dental implant osseointegration as well as its application in vitro and in vivo. The key words were “bisphosphonate, zoledronic acid, implant, osseointegration” in English and Chinese, respectively.

    RESULTS AND CONCLUSION: Zoledronic acid has been demonstrated to inhibit bone resorption and promote bone formation via local or systemic use, single or combined use with other drugs. However, the inhibition of osteoclasts by zoledronic acid is associated with the dose and action time of zoledronic acid. Thus, further investigation on the specific mechanisms of zoledronic acid at different dose and with different action time are warranted. We should further elucidate the risk factors and determinants of osteonecrosis of the jaw through clinical studies, and then find effective approaches to reduce the risk of jaw osteonecrosis and to maximize the positive effect of zoledronic acid in the dental implantation.

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    Progress in the repair of osteoporotic bone defects: scaffold implantation and local drug delivery
    Li Zu-hao, Wang Chen-yu, Wang Zhong-han, Gao Chao-hua, Shi Chen-yu, Yang Fan, Liu He, Wang Jin-cheng
    2018, 22 (18):  2939-2945.  doi: 10.3969/j.issn.2095-4344.0874
    Abstract ( 371 )   PDF (830KB) ( 224 )   Save

    BACKGROUND: With the development of chemical synthesis technology, the application of anti-osteoporosis drugs incorporated into scaffolds to promote bone regeneration in osteoporotic bone defects has become a hot issue nowadays.

    OBJECTIVE: To introduce bone tissue engineering scaffolds, and to discuss and summarize the application of the scaffolds carrying anti-osteoporosis drugs for osteogenesis in osteoporotic bone defects.
    METHODS: PubMed, Web of Science, Springerlink, Medline, WanFang and CNKI databases were retrieved with “osteoporosis, bone defect, scaffold” as key words for relevant articles published from 2005 to 2017. Initially, 201 articles were retrieved, and finally 64 articles were selected for further analysis.

    RESULTS AND CONCLUSION: With the development of biochemical synthesis technology, various types of tissue-engineered bone scaffolds have been used for the treatment of osteoporotic bone defects. For example, the modified calcium phosphate cement, β-tricalcium phosphate, and hydroxyapatite all can promote bone regeneration. However, the ability of conventional scaffolds to promote bone regeneration is severely damaged under the state of osteoporosis. In this case, an anti-osteoporosis therapy becomes necessary. Considering severe adverse effects of systemic anti-osteoporosis drugs and limited local bone regeneration, the combination of scaffold implantation and local drug delivery can promote osteoporotic bone defect healing. Importantly, to incorporate bone regeneration inducers into scaffolds and steadily release with their biological activity is the key to success. Bisphosphonate, strontium, bone morphogenetic protein 2 and parathyroid hormone, traditional Chinese medicine and mesenchymal stem cells are the drugs commonly combined with tissue-engineered bone scaffolds. With the development of biotechnology, genetically modified stem cell-scaffold composites have gradually appealed to researchers.

     

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    A meta-analysis on therapeutic efficiency of self-ligating versus conventional brackets for orthodontic correction
    Liu Yao, He Yun, Zeng Jie, Dai Feng-ling, Luo Yu-ru, Luo Jing, Ju Mei
    2018, 22 (18):  2946-2952.  doi: 10.3969/j.issn.2095-4344.0877
    Abstract ( 439 )   PDF (692KB) ( 193 )   Save

    BACKGROUND: The type of brackets is closely related to the efficiency of orthodontic treatment. A self-ligating bracket is characterized by low friction, simple operation, mild pain and discomfort, and it has been an issue of concern in orthodontics. In recent years, studies on the therapeutic efficiency of self-ligating brackets versus conventional brackets for orthodontic correction have been reported, but there is no conclusion.

    OBJECTIVE: To systematically compare the conventional and self-ligating brackets concerning treatment efficiency.
    METHODS: A computer-based search of PubMed, EMBASE, MEDLINE, WanFang, VIP and CNKI was performed for randomized controlled trials concerning self-ligating brackets versus conventional brackets for orthodontic correction. The keywords were “orthodontic brackets/ self-ligating, random” in English and “appliance/self-ligating/ conventional/orthodontic correction efficiency” in Chinese. The retrieve time was set from inception to December 2017. Stata12.0 software was used for meta-analysis following literature screening, data extraction and risk assessment of bias.

    RESULTS AND CONCLUSION: A total of 9 randomized controlled trials involving 603 patients were included. The results of meta-analysis on the efficiency of the two groups showed that there was no significant difference in overall treatment time, number of visits, time of alignment and time of space closure (P > 0.05). Only the time of chairside operation showed significant difference between the two groups (P < 0.05). These findings indicate that compared with the conventional bracket, the self-ligating bracket has no obvious advantage in the therapeutic efficiency.

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