Loading...

Table of Content

    08 April 2018, Volume 22 Issue 10 Previous Issue    Next Issue
    For Selected: Toggle Thumbnails
    Tissue-engineered bone constructed by icariin-induced periosteal cells repairs bone defects
    Zhong Xiu-xia, Luo Mei-lan
    2018, 22 (10):  1477-1482.  doi: 10.3969/j.issn.2095-4344.0704
    Abstract ( 251 )   PDF (1127KB) ( 122 )   Save
    BACKGROUND: Although icariin has a clear role in inducing differentiation of bone marrow stromal cells, no studies have reported on its use in proliferation of periosteal cells in animal experiments. Three-dimensional polycaprolactone scaffold is a new scaffold, and it has the characteristics of biodegradability, proper pore size, and good histocompatibility.
    OBJECTIVE: To investigate the effect of icariin on the proliferation of periosteal cells, to construct periosteal cells and three-dimensional scaffold composite tissue-engineered bone and study its therapeutic effect on radical defects in rabbits, so as to provide a new way for the treatment of bone defects .
    METHODS: The mandibular periosteum was obtained from the rabbit and the primary cells were obtained by tissue explant method. The passage 3 cells were planted on 24-well plates. In experimental group, icariin at 10-4, 10-3 and 10-2 mol/L were added into the corresponding cell culture wells; equal volume of PBS was added to control group; positive control group was treated with 10 μg/L basic fibroblast growth factor. The cell proliferation in each group was measured by MTT method on the 2nd, 4th, 6th and 8th days, respectively. The three-dimensional polycaprolactone scaffolds, 10-2 mol/L icariin and 107/L periosteum cells were placed in cell culture plates and cultured in vitro to construct the cell-scaffold complex. After the rabbit radical defect model was established, the model rabbits were randomized into three groups (n=15 per group), followed by implanted with scaffold complex (experimental group), polycaprolactone scaffold (polycaprolactone group) or nothing (control group). Pathological sections were taken at the 2nd, 4th and 8th weeks respectively for hematoxylin-eosin staining to observe the bone and count the number of osteoblasts. The X-ray films of the radius were obtained at the 4th week.
    RESULTS AND CONCLUSION: (1) The proliferation of periosteal cells induced by different concentrations of icariin, especially 10-2 mol/L icariin, was better than that in the control group (P < 0.05), Therefore, the optimal concentration of icariin was 10-2 mol/L. (2) At 4 weeks after transplantation, in the experimental group, there were more osterocytes and less microvessels; in the polycaprolactone group, there were more new vessels, less woven newly born bone and osterocytes; in the control group, the defect region was filled with more granulation tissue and less osterocytes. At the 8th week, complete healing in the defect region was observed in the cell-scaffold complex group, while partial healing in the polycaprolactone scaffold group. In the control group, however, fibroblasts and scar tissues were visible in the defect region, with presence of closed medullary cavity and nonunion. The number of osteocytes in the experimental group was significantly higher than that in the other two groups (P < 0.05). X-ray examination at the 4th week showed that the defect region in the experimental group achieved healing; in the polycaprolactone group, the callus formed and defect region connected partly; and there was a clear gap in the defect region of the control group. Our findings indicate that icariin at different concentrations can promote the proliferation of periosteal cells and the concentration of 10-2 mol/L has the greatest role. Icariin can induce proliferation of periosteal cells in the three-dimensional polycaprolactone scaffold, which contributes to bone repair.
    Figures and Tables | References | Related Articles | Metrics
    Effects of zinc ion contents on pro-osteogenic and antibacterial activities of micro-arc oxidation coatings
    Zhang Zhen-xiang
    2018, 22 (10):  1483-1487.  doi: 10.3969/j.issn.2095-4344.0705
    Abstract ( 361 )   PDF (1211KB) ( 136 )   Save
    BACKGROUND: Some studies have found that zinc ions have pro-osteogenic activity, while zinc ions at high levels are also reported to inhibit the differentiation of osteoblasts instead of the pro-osteogenic activity. In some studies, zinc ions that are injected into the surface of titanium have ineffective antibacterial effects. Therefore, further investigations on zinc ion’s effects as a controversial topic are required.
    OBJECTIVE: To observe the effects of zinc ion content on the pro-osteogenic and antibacterial activities of micro-arc oxidation coatings.
    METHODS: The coating was made on the surface of titanium by micro-arc oxidation method. The zinc ion content (atomic percentage) in the coating was set to 0.199%, 0.574%, and 1.995%, respectively, as low, medium and high dose groups. Untreated titanium plates were used as controls. MG63 cells were seeded on the surface of four groups of materials and tested for cell proliferation, morphological changes, and alkaline phosphatase activity. Staphylococcus aureus was inoculated on the surface of four groups of materials and the antibacterial rate was detected at 48 hours after inoculation. Bacterial adhesion was observed at 24 hours after inoculation.
    RESULTS AND CONCLUSION: Within 7 days of culture, the number of MG63 cells on the material surface gradually increased with time. The proliferative ability of cells was highest in the low-dose group, followed by the middle-dose and control group, and it was lowest in the high-dose group. After 48 hours of culture, the cells in the control, low-dose and middle-dose groups showed normal morphology and expanded pseudopodia, and some pseudopodia penetrated into the cell surface, while normal or intact cells were undetected in the high-dose group. Within 13 days of culture, the activity of alkaline phosphatase was the highest in the low-dose group, followed by the middle-dose and control groups, and the lowest in the high-dose group. There were significant differences in the activity of alkaline phoshatase between groups (P < 0.05). The antibacterial rate of the materials was 62.54% in the low-dose group, 69.84% in the middle-dose group, and 79.19% in the high-dose group, respectively. Findings from this study reveal that with the increase of zinc ion contents, the pro-osteogenic activity of micro-arc oxidation coatings decreased, while the antibacterial property improved.
    Figures and Tables | References | Related Articles | Metrics
    Bone regeneration imaging after bone grafting using phase-contrast computed tomography with synchrotron radiation
    Liu Yong-chao, Jian Jian-bo, Li Chang-chun, Sun Lian-lian, Hu Chun-hong
    2018, 22 (10):  1488-1492.  doi: 10.3969/j.issn.2095-4344.0706
    Abstract ( 347 )   PDF (1212KB) ( 102 )   Save
    BACKGROUND: With a clear distinction from traditional computed tomography (CT) imaging with information absorption, phase-contrast CT with synchronous radiation has implemented the microstructure imaging of soft  tissues in organisms with an unprecedented imaging mechanism.
    OBJECTIVE: To explore the synchrotron radiation phase-contrast CT imaging technology in the bone regeneration imaging after bone grafting.
    METHODS: Four New Zealand white rabbits were used to make a metaphyseal defect model. Then, model rabbits were randomized into a group with calcium phosphate bone grafting and a group with Bio-Oss bone grafting in the defects. The specimens were imaged by the synchrotron radiation phase-contrast CT and stained with hematoxylin-eosin and sirius red 2 weeks after bone grafting.
    RESULTS AND CONCLUSION: (1) Bio-Oss bone graft material group: Osteoid was observed not only around the graft material but also in the area far from the graft bone material as reticulate structure by the synchrotron radiation phase-contrast CT. Hematoxylin-eosin staining showed a large amount of red osteoid tissues arranged as trabecular bone, and a large amount of osteoblasts with obvious osteogensis. Sirius red-stained pathological sections were largely stained yellow, and there were round or oval osteoblasts with strongly expressed type I collagen. (2) Calcium phosphate bone graft material group: There was no reticulate structure shown by the synchrotron radiation phase-contrast CT, and the creep of osteoid tissues was only around the bone graft. Hematoxylin-eosin staining showed a large amount of red osteoid tissues, and sirius red-stained pathological sections were stained yellow and red. To conclude, the synchronous radiation phase- contrast CT can clearly display the regenerated structure of bone grafts.
    Figures and Tables | References | Related Articles | Metrics
    An influence on postoperative axial pain by laminoplasty combined with different fixations and bone grafting
    Gong Teng, Su Xue-tao, Xia Qun, Wang Jing-gui, Kan Shi-lian
    2018, 22 (10):  1493-1498.  doi: 10.3969/j.issn.2095-4344.0701
    Abstract ( 324 )   PDF (2480KB) ( 155 )   Save
    BACKGROUND: In clinical practice, inducible grafting from trimmed spinous process of hinge groove combined with different internal fixators is primarily applied to prevent postoperative axial pain after unilateral open-door cervical expansive laminoplasty.
    OBJECTIVE: To investigate the influence of autologous grafting of hinge groove combined with two internal fixators on postoperative axial pain after unilateral open-door cervical expansive laminoplasty.
    METHODS: We retrospectively reviewed 106 patients with multilevel ossification of cervical posterior longitudinal ligament who had underwent unilateral open-door cervical expansive laminoplasty with pedicle screw fixation (n=52, including grafting in 24 cases and non-grafting in 28 cases) or with mini-plate fixation (n=54, including grafting in 37 cases and non-grafting in 17 cases). Fusion rate of hinge groove, characteristics of postoperative axial pain and postoperative efficacy were evaluated by means of imaging methods.
    RESULTS AND CONCLUSION: All the 106 patients were followed up for 3.2-5.9 years, with no appearance of breaking or loosening of fixed appliances, disruption of the interior cortex of hinge groove. The 19 of 106 cases appeared to have postoperative axial pain, including 9 cases in the pedicle screw group (grafting: 4 cases, non-grafting: 5 cases) and 10 cases in the mini-plate group (grafting: 3 cases, non-grafting: 7 cases). Under the condition of pedicle screw fixation, there were no significant differences in the fusion rate at 3 months postoperatively and improvement rate of Japanese Orthopaedic Association Scale (JOA) score at final follow-up between the grating and non-grafting groups. After the implementation of mini-plate fixation, there was also no difference in JOA improvement rate at final follow-up between the grafting and non-grafting groups, but the fusion rate in the grafting group was significantly higher than that in the non-grafting group at 3 months postoperatively (P < 0.05). After pedicle screw fixation, there was no significant difference in incidence, onset time and severity of initial onset, duration, pain improvement between grafting and non-grafting groups. When fixed by mini-plates, pain duration and pain improvement
    were better in the grafting group than the non-grafting group (P < 0.05), and there were still no significant differences in the other indices between the two groups. To conclude, hinge grafting combined with pedicle screw fixation cannot affect onset characteristics of postoperative axial pain, while hinge grafting combined with mini-plate fixation can reduce duration of postoperative axial pain, improve prognosis, promote definite fusion of hinge groove, thereby remodeling alignment balance and biomechanical stability as soon as possible．
    Figures and Tables | References | Related Articles | Metrics
    Preparation and characterization of paeonol loaded brushite calcium phosphate cement
    Li Xiao-yu, Li Guang-da, Zhao San-tuan, Li Yong-kai, Zhao Peng-chao, Peng Huan
    2018, 22 (10):  1499-1505.  doi: 10.3969/j.issn.2095-4344.0815
    Abstract ( 338 )   PDF (2233KB) ( 128 )   Save
    BACKGROUND: Paeonol is an active ingredient of traditional orthopedic drugs, exhibiting pain easing, detumescence and promotion of bone healing. The brushite calcium phosphate cement possesses good biocompatibility, which can be completely degraded in the body. A large number of studies have addressed the modification of brushite calcium phosphate cement to make it more suitable for clinical applications.
    OBJECTIVE: To study the setting time, syringeability, compressive strength, drug delivery ability, antibacterial property and cell affinity of brushite calcium phosphate cement with the addition of paeonol.
    METHODS: The tricalcium phosphate was synthesized by calcium nitrate and diammonium hydrogen phosphate, followed by being calcined into β-tricalcium phosphate at 1 000 ℃. Chitosan was dissolved in citric acid solution to prepare the liquid phase. The composite bone cement was prepared by mixing paeonol, β-tricalcium phosphate and monocalcium phosphate with the liquid phase. The setting time, syringeability, phase composition, anti-collapsibility, compressive strength, degradation property, drug delivery ability, antibacterial property and cell affinity of the composite bone cement in vitro were evaluated.
    RESULTS AND CONCLUSION: The setting time of bone cement was 12-17 minutes, which was prolonged with the increase of paeonol release. Moreover, the loaded paeonol showed no significant effect on the phase composition, syringeability, anti-collapsibility, and compressive strength of the compound. However, the degradation rate and drug release content were significantly enhanced with the increase of paeonol release. The inhibition zone experiments showed that the paeonol loaded cement inhibited the growth of Escherichia coli, but was not sensitive to Staphylococcus aureus. HepG2 cells could adhere and proliferate on the material surface after 3 days co-culture, with clear cell pseudopodia arising from the cell surface under the scanning electron microscope.
    Figures and Tables | References | Related Articles | Metrics
    Titanium and nano-hydroxyapatite for bone defect repair in rats: effects on immune regulation
    Liu Feng, Liang Zai-ming
    2018, 22 (10):  1506-1510.  doi: 10.3969/j.issn.2095-4344.0707
    Abstract ( 425 )   PDF (4769KB) ( 175 )   Save
    BACKGROUND: Studies have shown that titanium has good biological properties and regulate osteoblast adhesion, proliferation and differentiation, but there are few reports on the effect of titanium materials on bone defect repair and on immune regulation in rats.
    OBJECTIVE: To investigate the effect of titanium materials in the repair of osteoporotic bone defect in rats and its effect on immune regulation.
    METHODS: Bilateral ovaries were removed from 30 Wistar rats to establish osteoporosis models. Three months after modeling, a percutaneous bone defect with the diameter of 2.5 mm was prepared on the distal femur of all the 30 rats. These model rats were then randomly divided into three groups with 10 rats in each group: negative control group without any intervention, hydroxyapatite group filled with nano-hydroxyapatite, and titanium material group filled with titanium material. Serum interleukin-1, tumor necrosis factor-α and interleukin-6 levels were measured by enzyme-linked immunosorbent assay after 5 days of intervention, and meanwhile, serum T-lymphocyte subsets were detected by flow cytometry. After 5 and 10 weeks of intervention, hematoxylin-eosin staining was used for morphological observation of the defect site.
    RESULTS AND CONCLUSION: (1) After 5 days of intervention, the levels of interleukin-1, tumor necrosis factor-α and interleukin-6 in the titanium material group were significantly lower than those in the negative control and hydroxyapatite groups (P < 0.05). (2) After 5 days of intervention, the levels of CD4+ and CD8+ and the ratios of CD4+/CD8+ in the titanium material group were significantly higher than those in the hydroxyapatite and negative control groups (P < 0.05). (3) Hematoxylin-eosin staining results showed that a small amount of bone tissues filled with a large amount of fibrous tissues and adipocytes formed in the negative control group at 5 and 10 weeks after intervention. A little bone formation was observed in the hydroxyapatite group at 5 weeks after intervention, and the implant began to degrade at 10 weeks and was gradually replaced by new bone tissues. A small amount of trabecular bones enriched with blood vessels arranged orderly in the titanium material group at 5 weeks after intervention; and at 10 weeks, the number of trabecular bone increased and the defect was basically healed. Taken together, the titanium plate can achieve good results in the repair of osteoporotic bone defects in rats, and moreover, it can control the immune response during the bone defect repair.
    Figures and Tables | References | Related Articles | Metrics
    Combined use of poly(methyl methacrylate) bone cement and injectable artificial bone implantation for senile degenerative thoracic osteoporotic vertebral compression fractures: study protocol for a randomized controlled trial
    Zhang Yuan, Ren Rong, Li Ze-qing, Hu Yi-bo, Li Ming
    2018, 22 (10):  1511-1516.  doi: 10.3969/j.issn.2095-4344.0708
    Abstract ( 311 )   PDF (1005KB) ( 145 )   Save
    BACKGROUND: Percutaneous kyphoplasty is an effective treatment method for senile degenerative thoracic osteoporotic vertebral compression fractures. However, its clinical long-term effect is controversial among scholars both inside and outside China. The poly(methyl methacrylate) (PMMA) bone cement commonly used in percutaneous kyphoplasty has good plasticity and formability, but its biocompatibility is not yet clear. Injectable artificial bone is a novel filling material to induce bone formation, but its long-term efficacy remains to be verified.
    OBJECTIVE: To compare the efficacy of OSTEOPAL®Plus PMMA bone cement and GeneX® injectable artificial bone graft in the treatment of senile degenerative thoracic osteoporotic vertebral compression fractures at 24 months postoperatively.
    METHODS: This is a prospective, single-center, open-label, randomized controlled clinical trial. A total of 378 patients with senile degenerative thoracic osteoporotic vertebral compression fractures will be recruited from the Department of Orthopedics, Affiliated Hospital of Qinghai University, China. The patients will be randomized into two groups and undergo percutaneous kyphoplasty. The PMMA group (n=189) will be treated with OSTEOPAL®Plus PMMA bone cement. The artificial bone group (n=189) will be treated with GeneX® injectable artificial bone. Follow-ups will be conducted at 1 week and at 3, 6, 12, and 24 months. The primary outcome measure will be the vertebral body height restoration rate at 24 months postoperatively to evaluate the repair effect of the damaged thoracic vertebra. The secondary outcome measures will be the vertebral body height restoration rate at 1 week and 3, 6, and 12 months postoperatively; the incidence of bone cement leakage at 1 week and 3, 6, 12, and 24 months postoperatively; the visual analog scale score, Oswestry Disability Index, compression rate of the anterior vertebral height, and thoracic morphology revealed by computed tomography preoperatively and at 1 week and 3, 6, 12, and 24 months postoperatively; and the incidence of adverse reactions at 1 week and 3, 6, 12, and 24 months postoperatively.
    DISCUSSION: Our results will verify whether OSTEOPAL®Plus PMMA bone cement and GeneX® injectable artificial bone graft are effective and safe for treating senile degenerative thoracic osteoporotic vertebral compression fractures in the short-term and at the 2-year follow-up. This study was approved by the Medical Ethics Committee of Affiliated Hospital of Qinghai University of China in November 2017 (approval number: 2017-11). The study protocol will be conducted in accordance with the Declaration of Helsinki, formulated by the World Medical Association. Written informed consent will be obtained from all participants who will be fully informed of study protocol and process. This trial was designed in December 2017. The recruitment of subjects and data collection will begin in July 2018. Outcome measures will be analyzed in September 2020. This trial will be completed in October 2020. The results of the trial will be reported in a scientific conference or disseminated in a peer-reviewed journal. This trial had been registered in the Chinese Clinical Trial Registry (registration No: ChiCTR1800015411). The version of this study protocol is 1.0.
    Figures and Tables | References | Related Articles | Metrics
    Implantation of beta-tricalcium phosphate combined with osteoblast-specific peptides for alveolar bone preservation in extraction sockets
    Zhuang Yan-qin, Chen Hui-min, Wu Qi-yue, Wang Ze-hua, Wu Ming-yue
    2018, 22 (10):  1517-1522.  doi: 10.3969/j.issn.2095-4344.0709
    Abstract ( 339 )   PDF (4887KB) ( 166 )   Save
    BACKGROUND: Previous findings show that osteoblast-specific peptides can promote the repair and regeneration of skull defects in rabbits, and β-tricalcium phosphate (β-TCP) is used as a scaffold to carry osteoblast-specific polypeptides. Both of them not only complement each other, but also fully exert dual effects of osteoinduction and bone conduction.
    OBJECTIVE: To investigate the effect of osteoblast-specific peptide on the preservation of the anterior tooth extraction site in rabbits, and to study the effect on the alveolar bone remodeling.
    METHODS: Twenty-seven New Zealand white rabbits were randomly divided into three groups (n=9 per group), and the right mandibular incisors were removed to establish the animal models of tooth extraction. β-TCP/osteoblast-specific peptide compounds were implanted in the experimental group, and pure β-TCP meal was implanted into the material group. The blank control group had no implantation. Three rabbits from each group were scarified at 4, 8 and 12 postoperative weeks, and tissue samples were prepared for gross observation, histomorphology measurements, and radiographic measurements of extraction socket healing.
    RESULTS AND CONCLUSION: (1) Imaging results showed that the relative length of residual alveolar bone after modeling was ranked as follows: the experimental group > the material group > the blank control group, and the difference was statistically significant among groups
    (P < 0.05). Cone-beam CT findings in the three groups changed as time went on. At 4 and 8 postoperative weeks, the implanted materials in the experimental and material groups gradually degraded; the bone mass in the experimental group was significantly higher than that in the material and blank control groups. At 12 postoperative weeks, the experimental group had basically completed the reconstruction of tooth socket, but there were still some bone defects in the material and blank control groups. (2) Histomorphological findings showed that at 4 postoperative weeks, the experimental group exhibited obvious bone deposition lines, and the bone trabecula was widened; in the material and blank control groups, the new bone was less. At 8 postoperative weeks, a small amount of undegraded scaffold was found in the experimental group, with mature lamellar bone, the amount of new bone tissues in the material group increased and osteoblasts were obviously detected in the blank control group. At 12 postoperative weeks, the bone remodeling in the extraction socket of the experimental group was basically completed; in the material group, there were still a small amount of scaffold materials and dense plate-like new bone; and in the blank control group, the new bone tended to be mature, and there was obvious lamellar structure. To conclude, osteoblast-specific peptides can effectively preserve the length of the residual alveolar bone after tooth extraction, promote the formation of new bone, and have the function of preserving the tooth extraction site.
    Figures and Tables | References | Related Articles | Metrics
    Biomechanical analysis of micro-implant anchorage in the infrazygomatic crest for the distal displacement of the upper dentition at different heights
    Yang Jian-hao, Han Lu, Li Ya-ru, Zhang Yue-lan
    2018, 22 (10):  1523-1528.  doi: 10.3969/j.issn.2095-4344.0710
    Abstract ( 334 )   PDF (1253KB) ( 130 )   Save
    BACKGROUND: In orthodontics, micro-implant anchorage in the infrazygomatic crest that cannot damage the tooth root can achieve an unobstructed overall movement of the upper dentition. However, little is reported on the stress and strain of the tooth and alveolar bone during the distal movement of the upper dentition.
    OBJECTIVE: To set up a three-dimensional finite element model to perform a biomechanical analysis of micro-implant anchorage in the infrazygomatic crest for the distal displacement of the upper dentition at different heights.
    METHODS: Cone-beam CT data from a female patient admitted for orthodontic treatment was saved in Dicom format, and imported into Mimics 16.01 software. Then, a three-dimensional model of the right maxilla and tooth dentition was made by automatically and manually selecting boundaries. The model was imported into Geomagic8.0 for removal of noise dots and smooth processing, and then it was imported into the Mimics16.01 software and meshed for the surface/body through 3 Matics software. Afterwards, three-dimensional models maxillary denture, archwires and traction hooks and implants were established by ProE5.0, and all the models were imported into ANSYS13.0 and assembled and analyzed for stress and strain analysis.
    RESULTS AND CONCLUSION: We successfully established the three-dimensional finite element model for biomechanical analysis of micro-implant anchorage in the infrazygomatic crest for the distal displacement of the upper dentition at different heights, and this model conformed to the anatomic features. With the increase of the height of traction hooks (1, 4, 7, 10 mm), the vertical stress of the maxillary teeth increased gradually, and had no correlation with the change of the horizontal stress. With the increase of the height of traction hooks, at the sagittal axis, the strain at midpoints of middle incisors, canine teeth, and first molars decreased gradually and the strain at the root of middle incisors and canine teeth also decreased gradually, but there was no change in the strain at the root of first molars. With the increase of the height of traction hooks, at the vertical axis, the strain at the midpoints and tooth root of middle incisors increased, while the strain of canine crown increased gradually and that of the canine root decreased; the strain at the midpoint of first molars changed a little, and the strain of the tooth root decreased gradually. The dentition rotated from clockwise to counterclockwise. To conclude, the three-dimensional finite element model made in the study is consistent with the anatomic structure, which provides a basis for biomechanical analysis of micro-implant anchorage in the infrazygomatic crest for the distal displacement of the upper dentition. The upper dentition impedance center located in the position of 4 to 7 mm of the arch wire can be used as the microimplant support site in the infrazygomatic crest.
    Figures and Tables | References | Related Articles | Metrics
    The computer-aided design and manufacturing of individualized miniscrew surgical guides based on a high-precision three-dimensional integrated digital maxillodental model
    Chen Yan-qu, Tang Min, Huang Xuan-ping, Zhou Feng-cheng, Wang Jia-xi
    2018, 22 (10):  1529-1533.  doi: 10.3969/j.issn.2095-4344.0711
    Abstract ( 430 )   PDF (1242KB) ( 121 )   Save
    BACKGROUND: Surgical guides designed based on a three-dimensional cone-beam CT (CBCT) model have been reported. However, CBCT cannot remodel fine soft tissue such as gums, and it can only be used to design a simple dental retainer with relatively poor stability.
    OBJECTIVE: To establish a high-precision three-dimensional (3D) integrated maxillodental model by matching CBCT model with 3D digital maxillodental model using 3D automatic registration method, based on which, we designed and manufactured individualized miniscrew surgical guides.
    METHODS: CBCT maxillodental models and laser-scanned dentition models obtained from six malocclusion cases were matched and overlapped using the 3D automatic registration method to fabricate the 3D integrated maxillodental model. Then, we accurately positioned and virtually implanted a micro-implant into the 3D integrated maxillodental model. Subsequently we prepared a high-precision individualized resin surgical guide by rapid prototyping technology. The inner diameter of the guide track was detected by a vernier caliper. Patients tried on the resin surgical guide, and then occlusion condition, guide seating and retention were detected.
    RESULTS AND CONCLUSION: Due to the high-precision registration of the model, all the resin surgical guide plates were suitable. The plate retention was enhanced after tooth clinching, and all the patients felt comfort when wearing the surgical guide plate, with no compression or other discomforts. The inner diameter of the guide track was (1.79±0.23) mm, and the measurement error was not statistically significant (P > 0.05). These findings demonstrate that the high-precision surgical guide plate based on the high-precision 3D integrated model can provide the foundation for further investigations on the clinical application of surgical guides.
    Figures and Tables | References | Related Articles | Metrics
    Biosafety evaluation strategy and practice of tissue induced biomaterials
    Zou Wen, Yuan Tun, Cai Yong-fu, Zheng Li-ping, Liang Jie
    2018, 22 (10):  1534-1539.  doi: 10.3969/j.issn.2095-4344.0712
    Abstract ( 496 )   PDF (4772KB) ( 166 )   Save
    BACKGROUND: Due to the complexity of tissue induced biomaterials, the current biosafety evaluation standard is not available. For years, to choose an effective evaluation strategy and practice in tissue induced materials has been always a hot topic, but still with no conclusion. The existence of this problem results in numerous issues for manufactures when conducting the biosafety evaluation of tissue induced medical devices.
    OBJECTIVE: To formulate the biosafety evaluation strategy that should be followed by the material samples at the research and development stage and to provides some ideas and lessons for the selection of the product biology experimental items to be listed and registered.
    METHODS: In 2016, a statistical analysis was carried out for biological test items of tissue induced biomaterials. Cytotoxicity, irritation and sensitization tests were the most commonly used tests for biomaterials and medical devices. A biosafety evaluation only via the above three tests had been applied in 58 kinds of materials with 81 batches of samples. In this study, immune toxicity tests were performed in 17 kinds of materials and biodegradation tests were done in some samples.
    RESULTS AND CONCLUSION: It had been found that different test programs or evaluation strategies may be adopted in the product development or listing registration stage. At early stage of development, cytotoxicity, irritation and sensitization tests are suitable for sample screening. In the later stage of research and development, more in-depth tests, such as subchronic toxicity, degradation and immunity toxicity, should be employed to meet the safety evaluation requirements.
    Figures and Tables | References | Related Articles | Metrics
    Effects of Col-Tgel, a bioactive material, on human tissue stem cells
    Yin Xiu-xiu, Hu Lin-ping, Zhu Cai-ying, Zhang Xiao-bing, Cheng Tao
    2018, 22 (10):  1540-1546.  doi: 10.3969/j.issn.2095-4344.0713
    Abstract ( 423 )   PDF (5253KB) ( 107 )   Save
    BACKGROUND: The traditional two-dimensional culture system has been widely used in the in vitro culture of human tissue stem cells, but it cannot really simulate the three-dimensional physiological microenvironment in the body, which is not conducive to the study of the biological behavior of human stem cells.
    OBJECTIVE: To detect the effect of the bioactivity of Col-Tgel in human hematopoietic stem cells (HSCs) and mesenchymal stem cells (MSCs) in vitro and in vivo, by constructing a three-dimensional culture system stimulating the physiological microenvironment of the body.
    METHODS: (1) In vitro co-culture: Green fluorescent protein labeled MSCs (MSCs-GFP) and human umbilical cord blood CD34+ cells were co-cultured in Col-Tgel for 3 days (three-dimensional culture group). Human umbilical cord blood CD34+ cells were cultured in Col-Tgel for 3 days as single culture group. MSCs-GFP and human umbilical cord blood CD34+ cells were co-cultured in Transwell chamber for 3 days as two-dimensional culture group. Human umbilical cord blood CD34+ cells were cultured routinely as control group. The percentage of CD34+CD38-CD45RA-CD90+ cells in each group was measured by flow cytometry. In situ immunofluorescence staining was used to detect the activity of cells that were co-cultured in Col-Tgel. (2) In vivo transplantation: NOD/SCID mice subjected to 24-hour X-ray irradiation were divided into two groups: in experimental group, MSC-GFP cells were resuspended in Col-Tgel and transplanted into the tibia of NOD/SCID mice; in control group, MSCs-GFP were resuspended in PBS and transplanted into the tibia of NOD/SCID mice. The MSC-GFP growth in the bone marrow was detected by two-photon/confocal microscopy at 3 days post transplantation.
    RESULTS AND CONCLUSION: (1) After co-culture in Col-Tgel for 3 days, the percentage of CD34+CD38-CD45RA-CD90+ cells in the three-dimensional culture group was 2.8 times that of the two-dimensional culture group, indicating that the MSCs significantly promoted the expansion of CD34+CD38-CD45RA-CD90+ cells in the Col-Tgel. The percentage of CD34+CD38-CD45RA-CD90+ cells in the three-dimensional culture group was increased by 4.5 times compared with the single culture group and increased by 1.5 times compared with the control group. Immunofluorescence staining showed that the cell viability of human MSCs and human umbilical cord blood CD34+ cells was not affected after co-cultured in Col-Tgel for 3 days. In the in vivo transplantation experiment, MSC-GFP cells could survive in the medullary cavity. In summary, Col-Tgel provides a new strategy for stem cell culture and in vivo growth by forming a three-dimensional system similar to the physiological environment in vivo.
    Figures and Tables | References | Related Articles | Metrics
    A new self-convertible inferior vena cava filter: in vitro experimental evaluation
    Gao Xi-xiang, Zhang Jian, Gu Yong-quan, Guo Lian-rui, Tong Zhu, Li Li-qiang, Li Jian-xin, Feng Zeng-guo
    2018, 22 (10):  1547-1552.  doi: 10.3969/j.issn.2095-4344.0714
    Abstract ( 416 )   PDF (1033KB) ( 130 )   Save
    BACKGROUND: Inferior vena cava filter is an effective way to prevent fatal pulmonary embolism. The existing filters have some shortcomings that limit the clinical application.
    OBJECTIVE: To evaluate the feasibility and capture efficiency of a new self-convertible inferior vena cava filter (SCF) in vitro.
    METHODS: The biodegradable switch was constructed of a copolymer of ε-caprolactone and L-lactide (75%/25%, PCLA75). The biodegradable switch bound together with the apices of the convertible struts to make the self-convertible filter. The deformability and capture efficiency of the filter were tested in an in-vitro flow model with three different diameters (22, 25, 28 mm). A total of 15 filters were implanted both in the vertical and horizontal positions, and the tilt angle of the filter was tested after release. To accelerate switch degradation, a lipase perfusate was injected into the flow model and refreshed every 8 hours until conversion.
    RESULTS AND CONCLUSION: (1) All the filters were successfully implanted without tilting, both in the vertical and horizontal positions in the three different diameter models. (2) All the 15 SCFs were converted successfully without tilting, structural damage, and displacement. (3) The capture efficiency of the SCF had significant difference between the different diameter of the models, the size of the embolus and the position of the two models (P < 0.001). The mean capture efficiency was 82.5%, and the capture efficiency exhibited a downward trend with the increase of pipe diameter, the decrease of emboli size, and the position of pipeline changing from vertical to horizontal. All these results show that the SCF is feasible and highly efficient.
    Figures and Tables | References | Related Articles | Metrics
    Preparation and in vitro transdermal permeation of cyclosporin A microemulsion papua cream eye patch
    Chen Min, Xu Li-jiang, Weng Jing-ning, Shangguan Xiao-hui, Yan Jun, Huang Jin-qi, Chen Dan-na
    2018, 22 (10):  1553-1558.  doi: 10.3969/j.issn.2095-4344.0715
    Abstract ( 409 )   PDF (1400KB) ( 107 )   Save
    BACKGROUND: Immune eye diseases such as hyperthyroidism exophthalmos and uveitis seriously endanger the eye health of patients, which are common and difficult eye diseases. Current treatments for these diseases include oral administration of hormones and immunosuppressive agents, with poor efficacy, recurrent attacks and poor prognosis. Meanwhile, these treatments can induce systemic adverse reactions. Lymphocytes are directly or indirectly involved in these diseases. Therefore, we try to make papua eye patch carrying immunosuppressant, and deliver the drug through the topical use. Cyclosporin A microemulsion targeting lymphocytes can treat or control palpebral lymph nodes involved in the immune eye diseases. It is a topical method rather than the systemic medication, which is targeted and has small doses of drugs. If possible, this treatment can effectively treat immune eye diseases and avoid systemic drug adverse reactions and long-term adverse reactions induced by original drugs.
    OBJECTIVE: To study the preparation of cyclosporin A microemulsion papua cream eye patch, and its transdermal absorption characteristics in vitro.
    METHODS: Cyclosporine A microemulsion was fully mixed with water-soluble polymer materials at a ratio of 1 mg:1 mL, including sodium polyacrylate, polyvinyl alcohol, polyvinylpyrrolidone, gelatin, peach gum, sodium carboxymethylcellulose, hydroxypropylcellulose, and then coated onto the non-woven fabric to prepare Babu cream. Permeability of the Babu cream on the abdominal skin of ICR mice was determined by Franz diffusion cell method. High-performance liquid chromatography was used to detect the concentration of cyclosporine A, and skin irritation and anaphylaxis were also measured.
    RESULTS AND CONCLUSION: Cyclosporin A microemulsion papua cream eye patch was successfully prepared with appropriate viscosity, good permeability, good permeability, comfortable application, no skin irritation and allergic reaction. The content of cyclosporine A was    10 mg/tablet, and the concentration was 1 g/L. The concentration of cyclosporine A microemulsion increased with the increase of time, and it had good transdermal effect. This study proved that it is feasible to prepare cyclosporine A microemulsion into papua patch. It has good performance in skin permeability, adhesion and skin comfort.
    Figures and Tables | References | Related Articles | Metrics
    In vitro degradation rate of concentrated growth factors in simulated body fluid and simulated saliva fluid
    Zou Xin-ming, Huang Na, Wang Yuan-qin, Li Shao-bing, Tang You-chao
    2018, 22 (10):  1559-1564.  doi: 10.3969/j.issn.2095-4344.0716
    Abstract ( 532 )   PDF (1480KB) ( 153 )   Save
    BACKGROUND: Bioabsorbable biomaterials are of crucial importance in tissue engineering applications, and various factors affect their degradation.
    OBJECTIVE: To compare the degradation characteristics of concentrated growth factor (CGF) clot and CGF membrane in simulated body fluid (SBF) and simulated saliva fluid (SSF).
    METHODS: Fifteen volunteers were selected, and human blood samples were collected for the preparation of CGF clot or CGF membrane. All specimens from each subject were averagely divided into four groups: group A, CGF clot in SBF; group B, CGF clot in SSF; group C, CGF membrane in SBF; group D, CGF membrane in SSF. The specimens were subjected to the immersion test. The average daily rate of degradation of each group was calculated after the samples were thoroughly degraded, and weight loss ratio per unit time was also determined.
    RESULTS AND CONCLUSION: (1) The mean degradation time in groups A-D were (14.0±0.7), (9.7±0.9), (9.9±1.2) and (7.2±0.7) days, respectively. (2) By comparing CGF membrane with CGF clot in the same simulated fluid, the average daily degradation rate of CGF clot (groups A, B) was statistically significantly lower than counterparts of CGF membrane (groups C, D) (P < 0.05). By comparison between SBF and SSF, the average daily degradation rate in the SBF (groups A, B) was significantly lower than counterparts in the SSF (groups C, D) (P < 0.05). Overall, the degradation rate of CGF membrane is higher than that of CGF clot under the same degradation environment; for CGF membrane or CGF clot, the degradation rate in SSF is higher than that in SBF.
    Figures and Tables | References | Related Articles | Metrics
    Cytobiological effect of micro-arc oxidation coating on 3D-printed titanium alloy scaffold
    Li Jiong-jiong, Zou Qin, Hu Fu,Chen Jie, Li Ji-dong, Li Shu-jun, Hao Yu-lin, Li Yu-bao, Zuo Yi
    2018, 22 (10):  1565-1572.  doi: 10.3969/j.issn.2095-4344.0717
    Abstract ( 459 )   PDF (2119KB) ( 146 )   Save
    BACKGROUND: Micro-arc oxidation (MAO) treatment can improve the biological properties of titanium alloy implants. Previous studies mostly focused on the evaluation of titanium alloy plate, while the effects of the MAO-modified 3D titanium scaffold on the cell growth and differentiation were rarely reported.
    OBJECTIVE: To investigate the effect of MAO coating on the biological performance of cells seeded onto the 3D-printed porous titanium alloy scaffold.
    METHODS: Rat bone marrow mesenchymal stem cells were seeded onto the MAO-modified Ti6Al4V alloy scaffolds (experimental group) and unmodified scaffolds (control group). After 4 and 7 days of culture, cell/scaffold constructs were retrieved and processed for the assessment of cell morphology by using scanning electron microscopy, cytoskeletal staining analysis and cell viability assay were also evaluated. At 4, 7 and 11 days of culture, the levels of alkaline phosphatase and osteocalcin in the cell supernatant were detected. At 1, 4, 7 and 11 days of culture, the cell proliferation rate was measured using the MTT assay.
    RESULTS AND CONCLUSION: (1) At 4 and 7 days of culture, live/dead staining showed that the bone marrow mesenchymal stem cells grew well on the two kinds of scaffolds. The analysis of cytoskeleton staining showed that the cytoskeleton of the experimental group was stereo and polygonal, while the cells on the scaffold surface in the control group were flat and spindle-shaped, spreading along the macro structure of the scaffolds. Under the scanning electron microscopy, the cells in the experimental group arranged closely and spread in a good condition, with interconnected lamellipodia and filopodia that firmly adhered to the scaffold surface in an anchor-shaped structure; in the control group, less filopodia interconnected, less extracellular matrix, and flat and sheet-like cells were observed. (2) With the time increase, the levels of alkaline phosphatase and osteocalcin increased gradually in both groups. The alkaline phosphatase level in the experimental group was significantly higher than that in the control group at 7 and 11 days of culture (P < 0.05), while the osteocalcin level was higher in the experimental group than the control group at 11 days of culture (P < 0.05). (3) With the prolongation of culture time, the number of cells in the two groups increased gradually. The number of cells cultured in the experimental group was significantly higher than that in the control group at 7 and 11 days of culture (P < 0.05). To conclude, the MAO-modified titanium alloy scaffold is favorable for cell adhesion, proliferation and differentiation.
    Figures and Tables | References | Related Articles | Metrics
    Effects of titanium implant surface modification on macrophage polarization and osteogenesis
    Li Ying, Li Chang-yi
    2018, 22 (10):  1573-1579.  doi: 10.3969/j.issn.2095-4344.0718
    Abstract ( 429 )   PDF (1126KB) ( 170 )   Save
    BACKGROUND: A single use of bone-forming cells to evaluate the biological properties of titanium implant materials cannot meet the demands of early and long-term stable osseointegration. In order to fulfill the objective mentioned above, it is necessary to understand the interaction between implant and body at the interface of implantation. It is also urgent to consider the invaluable function of immunological factors including macrophage, so as to guide the implant surface modification.
    OBJECTIVE: To review the influence of physical, chemical and biological surface modifications of implants on the macrophage polarization and osteogenesis.
    METHODS: The first author conducted a computer-based retrieval of PubMed, Springerlink, Web of Science, ScienceDirect, CNKI, CqVip and WanFang databases for relevant articles published from January 2010 to December 2017. The key words were “titanium, implant, macrophage, polarization, osteogenesis” in English and Chinese, respectively.
    RESULTS AND CONCLUSION: Macrophages represent the first and the most abundant cells in contact with these implant materials and act as main effector cells in the intrinsic immune response. Surface modifications of implants play an important role in osseintegration by a M1 “tissue-inflammatory” polarization or M2 “wound-healing” activation. Furthermore, implant surface modification also affects the osteoinductive ability of macrophage. Future research intends to explain the bone healing mechanism between implant and host tissues from the immunological aspect and develop new-type titanium implants. New surface modification methods of implants, which could induce osteogenesis and acquire bone coupling and homeostasis, will be developed to fulfill early- and long-term stable osseointegration. 
    Figures and Tables | References | Related Articles | Metrics
    Advances in the construction of a scaffold for cardiac tissue engineering containing homogeneous and stable carbon nanotubes
    Chen Dian, Hu Qing-lin, Zhou Mei-ling, Hong Xian, Sun Xiao-xi, Xi Jiao-ya
    2018, 22 (10):  1580-1585.  doi: 10.3969/j.issn.2095-4344.0719
    Abstract ( 293 )   PDF (1339KB) ( 141 )   Save
    BACKGROUND: How to efficiently and uniformly disperse carbon nanotubes (CNTs) into a tissue-engineered scaffold is crucial to construct an ideal CNTs-Polymer composite scaffold and it is also a hotspot of research in the tissue engineering.
    OBJECTIVE: To review the advances in the methodology progress of constructing a scaffold for cardiac tissue engineering, which contains uniformly and stably dispersed CNTs.
    METHODS: The Web of Science Core Collection and PubMed were searched by the first author for related papers about CNTs dispersion in the cardiac tissue engineering published from October 2004 to January 2017. The key words were “carbon nanotubes, dispersion, cardiac tissue engineering” in English. Original research papers were searched, which were screened through titles, abstracts and contents, and then reviewed.
    RESULTS AND CONCLUSION: CNTs are easy to aggregate because of high surface area, high aspect ratio and rough surface. Thus, it is one of the key points to construct an ideal CNTs-Polymer composite scaffold that whether CNTs could be uniformly and stably dispersed in polymer scaffolds. In the cardiac tissue engineering, covalent or non-covalent surface modification of CNTs significantly enhances the uniformity and stability of CNTs in the polymer scaffolds, which is conducive to construct the uniformly and stably CNTs-dispersed scaffold for cardiac tissue engineering, leading to notable improvement in mechanical and electrical properties of engineered cardiac tissues.
    Figures and Tables | References | Related Articles | Metrics
    The application of beta-sheet self-assembling peptide hydrogels in neural tissue engineering
    Wei Wei, Liu Yan-fei, He Yang, Zhang Ling
    2018, 22 (10):  1586-1592.  doi: 10.3969/j.issn.2095-4344.0720
    Abstract ( 303 )   PDF (1251KB) ( 182 )   Save
    BACKGROUND: Self-assembling peptides, which allow for an optimal control over the scaffold structure and composition, are described as the innovative tissue-engineered scaffolds in the field of biological medicine.
    OBJECTIVE: To summarize the biological features of β-sheet self-assembling peptides and current research progress in the neural tissue engineering.
    METHODS: We took “β sheet, self-assembling peptide, hydrogel, neural stem cell, neural tissue engineering” as the key words in Chinese and English, respectively, to retrieve the related literatures (2000-2017) from PubMed, CNKI, WanFang databases based on internet search.
    RESULTS AND CONCLUSION: β-sheet self-assembling peptide, designed to function as an engineered mimic of the extra-cellular matrix (ECM), may be used with as a medium to direct growth and axonal connection, promoting neural stem cells adhesion, migration, division, outgrowth, neurogenesis and synaptogenesis. The self-assembling peptides RADA16, LDLK12, QL6 and their functionalized sequences have been proven to be of good utility. As the excellent performance of inducing peripheral nerve regeneration, mediating spinal cord injury and attenuating neuroinflammation, β-sheet self-assembling peptides have promising applications in the neural tissue engineering.
    Figures and Tables | References | Related Articles | Metrics
    Application prospects of compound gelatin-methacryloyl hydrogel in bone tissue engineering
    Liu Zhao-xing, Wu Xing, Lin Huan-huan, Liu Sha, Chen Xiang-jun
    2018, 22 (10):  1593-1598.  doi: 10.3969/j.issn.2095-4344.0721
    Abstract ( 465 )   PDF (1179KB) ( 136 )   Save
    BACKGROUND: Compound gelatin-methacryloyl (GelMA) hydrogel has been shown to have unique advantages in bone, cartilage, myocardium, and vascular regeneration.
    OBJECTIVE: To summarize the novel progress of compound GelMA hydrogel for bone tissue engineering.
    METHODS: PubMed database and CNKI database from 2010 to 2017 were searched by using the keywords of “gelatin, methacrylamide, hydrogel, hydroxyapatite, bone tissue engineering, bone regeneration, seed cells, microenvironment” in Chinese and English, respectively.
    RESULTS AND CONCLUSION: Inorganic components can be added in a specific way into the compound GelMA hydrogel to prepare tissue-engineered bone using photolithography, microfluidics, microfabrication and 3D printing techniques. The prepared tissue-engineered bone has similar structural, mechanical and biological properties to natural bone tissue, and importantly, it has osteogenic ability. Gene-modified seed cells that are co-cultured with the compound GelMA hydrogel in a 3D environment are found to grow well and express some genes related to bone regeneration and vascular regeneration. Therefore, the compound GelMA hydrogel has a good osteogenesis effect in vitro, which is an excellent material for bone tissue engineering.
    Figures and Tables | References | Related Articles | Metrics
    Current advances in the drug-loading preparation of poly(lactic-co-glycolic acid) microspheres
    Qiu Xiao-ming, Zhen Ping, Li Song-kai
    2018, 22 (10):  1599-1604.  doi: 10.3969/j.issn.2095-4344.0722
    Abstract ( 728 )   PDF (1477KB) ( 158 )   Save
    BACKGROUND: Existing flaws have been found in the production process of poly(lactic-co-glycolic acid) (PLGA) copolymer microspheres, which lead to residual solvent, low drug loading rate and low encapsulation efficiency of sustained-release microspheres.
    OBJECTIVE: To review different methods for preparing PLGA microspheres from the following aspects: basic principles, advantages/ disadvantages, indications and future development.
    METHODS: We retrieved CNKI, PubMed and Google scholar to access the articles related to the technique process of preparing PLGA microspheres published from January 2012 to April 2017, including experiment and application research on the principles and advantages/ disadvantages of the various processes.
    RESULTS AND CONCLUSION: To date, the main methods to prepare PLGA microspheres include single/re-emulsion solvent evaporation method, spray drying method, hydrogel template method, microfluid, coaxial electrostatic spraying, phase separation method, and supercritical fluid extraction. However, no valid evidences suggest that there is a technique that completely solves all potential problems, such as drug encapsulation and release, residual solvent and appropriate shape and size. Combination and modification of the production processes is expected to develop novel PLGA microspheres with ideal encapsulation efficiency and stable drug release.
    Figures and Tables | References | Related Articles | Metrics
    Socket shield technique for peri-implant tissue preservation in esthetics zone
    Chen Hui-hong, Wei Song-guan, Pang Bo, Wang Ling-fei, Qin Yuan, Xie Liu-rong, Liao Hong-bing
    2018, 22 (10):  1605-1610.  doi: 10.3969/j.issn.2095-4344.0723
    Abstract ( 587 )   PDF (1243KB) ( 692 )   Save
    BACKGROUND: Absorption of the alveolar bone subsequent to tooth extraction is a long-term process, especially in the anterior tooth region where the buccal part of the ridge undergoes a prominent remodeling process after tooth extraction. Socket shield technique (SST) recently reported may be a new choice for peri-implant tissue preservation.
    OBJECTIVE: To give an overview on the principle, interface basis and application of SST in implant dentistry.
    METHODS: The first author searched the PubMed, Ovid, CNKI, VIP and WanFang databases for relevant articles published from January 1990 to October 2017. The keywords were “socket shield technique; root-membrane technique; root-implant; implant proximity to teeth; dental-contected implants; dentointegration; cementum formation on implant surface” in Chinese and English, respectively.
    RESULTS AND CONCLUSION: SST aims to maintain alveolar bone and gingival tissues by preserving partial tooth root with its periodontium-bundle bone intact, which is an alternative strategy for tissue preservation in esthetics zone.  
    Figures and Tables | References | Related Articles | Metrics
    Three-dimensional bioprinting of tissue/organ analogues: a review on techniques, materials and processes
    Wang Xue-xin, Zhang Ming-jian, Li Xiao-bing, Han Wei-xin, Li Jin-qiao
    2018, 22 (10):  1611-1617.  doi: 10.3969/j.issn.2095-4344.0724
    Abstract ( 469 )   PDF (1260KB) ( 169 )   Save
    BACKGROUND: Three-dimensional (3D) bioprinting technology has a huge potential in the tissue engineering field, which is expected to create simple tissue/organ analogues with good biological histocompatibility and biological functions by using living cells and biomaterials.
    OBJECTIVE: To analyze the characteristics of 3D bioprinting technology and all kinds of biomaterials, and to explore its application in the preparation of tissues/organs analogues.
    METHODS: Relevant articles published from 1998 to 2017 were searched in PubMed, Web of Science, MEDLINE, and WanFang databases. The keywords were “3D bioprinting, 3D bioprinting technology, biomaterial, tissue engineering” in English and Chinese, respectively. A total of 88 articles were initially searched and 47 eligible articles were finally reviewed in accordance with the inclusion and exclusion criteria.
    RESULTS AND CONCLUSION: 3D bioprinting techniques mainly include inkjet technique (thermal inkjet and piezoelectric inkjet), pressure-assisted technique, laser-assisted technique, and stereolithography technique (single-photon-based and two-photon-based). The bio-ink consists of living cells, natural polymers and synthetic polymers. 3D bioprinting has exhibited a huge potential in the manufacture of living cell-containing tissue/organ analogues. Despite the fact that it has been widely studied, currently used 3D bioprinting techniques can only be used to prepare relatively simple structures with simple biological functions. Research on the specific tissue/organ analogues with living cells are still in its infancy.
    Figures and Tables | References | Related Articles | Metrics
    Biological scaffolds and mesenchymal stem cells in bone tissue engineering
    Liu Xiang-jie, Song Ke-guan
    2018, 22 (10):  1618-1624.  doi: 10.3969/j.issn.2095-4344.0725
    Abstract ( 347 )   PDF (1086KB) ( 111 )   Save
    BACKGROUND: The clinical treatment of bone defects is facing many problems. In order to solve the problem, the development of scaffold materials for bone tissue engineering has been an issue of concern.
    OBJECTIVE: To review the clinical application and development prospect of biological scaffold materials and mesenchymal stem cells in bone tissue engineering.
    METHODS: PubMed and CNKI databases were retrieved for the articles regarding bone tissue engineering published from January 2000 to December 2016. The key words were “bone tissue engineering; biological scaffold; mesenchymal stem cells” in English and Chinese, respectively. Articles addressing biological scaffolds and mesenchymal stem cells were included, except for repetitive research and Meta-analysis articles
    RESULTS AND CONCLUSION: Current biological scaffolds mainly include synthetic scaffold materials (polyvinyl alcohol, polylactic acid, polyglycolic acid, poly(lactic-glycolic acid)) and natural scaffold materials (collagen, chitosan, gelatin, silk fibroin). Each material has its own merits and demerits. Mesenchymal stem cells have a strong self-replicating and multi-directional differentiation ability, which are considered to be relatively ideal seed cells. Based on the characteristics of the components of biological scaffolds and the proliferation and multi-directional differentiation ability of mesenchymal stem cells, it is of great importance for bone defect repair to design and construct ideal biological scaffold materials with better repair function. Construction of a mesenchymal stem cell/3D scaffold complex is still in its infancy. However, the clinical application of biological scaffolds and mesenchymal stem cells in bone tissue engineering is expected to be achieved with the development of nanomaterials, international regenerative medicine and biomimetic science.
    Figures and Tables | References | Related Articles | Metrics
    Polyethylene glycol: an expert of cellular camouflage confusing the immune system
    Tian Ying, Wu Jie, Wang Shuang-yong
    2018, 22 (10):  1625-1633.  doi: 10.3969/j.issn.2095-4344.0726
    Abstract ( 543 )   PDF (1476KB) ( 166 )   Save
    BACKGROUND: Cell therapy, recombinant proteins and biomacromolecule preparations have been widely used in clinical practice; however, transplant rejections caused by xenogeneic proteins limit the safe and reusable use of such macromolecules.
    OBJECTIVE: To review the immunocamouflage mechanism of polyethylene glycol and the current application in the modification of macromolecules or biological vectors.
    METHODS: The authors retrieved articles about the immune camouflage of polyethylene glycol in WanFang, VIP and PubMed databases by the keywords as follows: “polyethylene glycol; immunocamouflage or immune camouflage; transplantation, and rejection” in Chinese and English, respectively.
    RESULTS AND CONCLUSION: Polyethylene glycol produces an immune camouflage by forming a stereoscopic charge barrier. The pegylation on the cell surface inhibits the adhesion, recognition and immune pathway involved in the heterogeneous recognition, which can interfere with many aspects of the immune response. The pegylated erythrocytes, islet cells, and lymphocytes show a decrease in the immunogenicity and a prolonged survival after allogeneic or xenotransplantation. Some factors including concentration, molecular weight, modification time, pH value can affect the immune camouflage of polyethylene glycol. The anti-PEG antibody and its effects need to be further elucidated.
    Figures and Tables | References | Related Articles | Metrics
    Influence of sodium hypochlorite irrigants on the bonding of fiber posts to root canals: a Meta-analysis
    Wang Wang, Wu You, Liu Xing-rong
    2018, 22 (10):  1634-1640.  doi: 10.3969/j.issn.2095-4344.0727
    Abstract ( 314 )   PDF (1303KB) ( 91 )   Save
    BACKGROUND: Currently, whether the use of sodium hypochlorite (NaOCl) influences the bond strength of fiber posts is still uncertain
    OBJECTIVE: To evaluate the influence of NaOCl on the bond strength of fiber posts by Meta-analysis．
    METHODS: Randomized controlled trials about the impact of NaOCl irrigation to the bond strength of fiber posts were retrieved from PubMed, EMbase, Web Of Science, OVID, CBM, ClinicalKey, CNKI, CqVip and WanFang databases, and other databases through manual retrieval as well. The deadline of the collection was December 31, 2016, with no limit of regions and languages. A Meta-analysis was performed with the bond strength of fiber posts as an indicator.
    RESULTS: A total of 11 randomized controlled trials were included. In the experimental group (NaOCl group), the root canal was rinsed with NaOCl, and dried followed by fiber post bonding using the total-etching system, the self-etching system and the self-adhesive system. In the control group, the root canal was washed with pure water or normal saline. Meta-analysis showed that weighted mean difference (WMD) (NaOCl group/control group)=-0.90, 95% confidence interval (CI) (-1.50, -0.31), Z=2.97, P=0.003. Subgroup analysis showed that WMD (total-etching: NaOCl group/control group)=-2.38, 95% CI (-4.86, 0.10), Z=1.88, P=0.06; WMD (self-etching: NaOCl group/control group)=-1.22, 95% CI (-2.17, -0.28), Z=2.55, P=0.01; WMD (self-adhesive: NaOCl group/control group)=-1.97, 95% CI (-2.30, -1.64), Z=11.73, P < 0.000 01. As the limited number of enrolled samples in the total-etching group and self-etching group results in a higher heterogeneity, further investigations are warranted. The present data suggests that irrigating the surface of root canals with NaOCl alone has negative impact on the bond strength of fiber posts using the self-adhesive system．
    Figures and Tables | References | Related Articles | Metrics