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    08 August 2017, Volume 21 Issue 22 Previous Issue    Next Issue
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    Polylactic acid-polyglycolic acid lumbar interbody fusion cage full of broken bones versus autologous bone: an influence on the spinal stability?

    Song Hong-ge, Li Xue-tao, Hao Guang-hui, Zhang Qin-an, Han Bing, Chen Li, Hai Yu-jie, Liu Hua-feng, Chen Yan-chao, Wang Jia-shuang
    2017, 21 (22):  3445-3451.  doi: 10.3969/j.issn.2095-4344.2017.22.001
    Abstract ( 332 )   PDF (1258KB) ( 193 )   Save
    BACKGROUND: Along with the widespread application of biodegradable materials in the field of medicine and the in-depth research of biomechanics, the drawbacks of traditional medical metal materials are increasingly appearing. In recent years, researchers at home and abroad focus on biodegradable materials that are represented by high molecular polymer to seek new breakthroughs in the field of spinal instability.
    OBJECTIVE: To investigate biomechanical changes of polylactic acid-polyglycolic acid (PLGA) lumbar interbody fusion cage in the body and discusses its feasibility for treating segmental instability of the spine.
    METHODS: Forty-two healthy pigs (9 months old) were randomly divided into two groups (n=21), and L4/5 intervertebral disc nucleus pulposus was removed in all animals. In experimental group, PLGA lumbar interbody fusion cage filled with broken bone was implanted; and in control group, autologous bone was implanted. X-ray was performed to observe the fusion of operation segments at 4, 12 and 72 weeks postoperatively. Feasibility of fibrous fusion was measured by biomechanical test. Histologically, bone graft fusion at the surgical site and material degradation were detected.
    RESULTS AND CONCLUSION: (1) Imaging examination: Bone graft fusion in two groups was not visible at 4 weeks after operation. Evidence of increasing fusion was found in the experimental group at 12 weeks after operation; a visible part of the bone bridge was found in the control group, in which there was one case of fusion. Degradation of the fusion cage with one case of fusion in experimental group was found after 72 weeks after operation, and two cases of fusion in the control group. (2) Biomechanical test: There was no difference in the spinal range of motion between the two groups in different states at 4 weeks after operation (P > 0.05). The spinal range values of motion at most of the states at 72 weeks after operation were significantly lower than those at 4 weeks after operation. (3) Cell histology observation: With the passage of time, the materials in the experimental group degraded gradually; new bone grew slowly and then fast, with bone fusion step by step. Fusion results were similar in the two groups. Our experimental findings indicate that the PLGA lumbar fusion cage has good biocompatibility. In addition to the individual state (left flexion), the mechanical properties of the fusion cage are similar to that of autogenous bone, and the fusion cage enables the segmental reconstruction of the pig spine to the maximum extent.
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    Unilateral percutaneous vertebroplasty with bone cement plus hyperextension position reset for Kümmell disease in the elderly

    Tan Guo-qing, Li Yan, Gan Dong-hao, Deng Dong-huan, Xu Zhan-wang
    2017, 21 (22):  3452-3457.  doi: 10.3969/j.issn.2095-4344.2017.22.002
    Abstract ( 356 )   PDF (1307KB) ( 199 )   Save
    BACKGROUND: Percutaneous vertebroplasty with bone cement plus hyperextension position reset for acute thoracolumbar vertebral osteoporotic compression fractures has been reported to achieve good clinical efficacy.
    OBJECTIVE: To evaluate the efficacy of unilateral percutaneous vertebroplasty with bone cement plus hyperextension position reset for Kümmell disease in the elderly.
    METHODS: Twenty-two old patients with Kümmell disease were included, involving 8 males and 14 females, aged 55-84 years old, and the injuried vertebrae included T11 (n=2), T12 (n=8), L1 (n=7), L2 (n=4), L3 (n=2), L4 (n=2), and L5 (n=1). All patients underwent the unilateral percutaneous vertebroplasty with bone cement plus hyperextension position reset.The visual analogue scale and the Oswestry Disability Index scores, vertebral body height as well as vertebral kyphosis angle were determined before and after treatment.
    RESULTS AND CONCLUSION: (1) All patients were successfully operated, pain relieved or disappeared within 24 hours postoperatively. No spinal cord injury, pulmonary embolism and other complications were found. One patient presented with cement leakage without obvious clinical symptoms; two patients had non-adjacent vertebral fractures during follow-up. (2) The visual analogue scale and Oswestry Disability Index scores at 1 day postoperatively were significantly lower than those at baseline (P < 0.05). (3) The anterior, medial and posterior height of involved vertebral body, kyphotic angle of involved vertebral body at 1 day postoperatively were significantly higher than those at baseline (P < 0.05). (4) These results manifest that unilateral percutaneous vertebroplasty with bone cement plus hyperextension position reset to treat Kümmell disease in the elderly can significantly relieve back pain, restore partial vertebral height, correct local kyphosis and improve functional recovery of the injured vertebrae.
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    Impaction bone grafting with morselized bone and bone paste for acetabular defects in adult Crowe III type developmental dysplasia of the hip
    Wu Tian-hao, Guo Jiang, Zhang Cai-dong, Fan Zhong-wei, Wang Sen, Liu Shao-feng, Tan Mei-yun
    2017, 21 (22):  3458-3463.  doi: 10.3969/j.issn.2095-4344.2017.22.003
    Abstract ( 357 )   PDF (1233KB) ( 176 )   Save
    BACKGROUND: Considering the risk of lack of bone in revision and the bone coverage of component, it is advisable to use bone grafting to increase bone stock in patients with adult Crowe type III developmental dysplasia of the hip (DDH) in the first total hip arthroplasty (THA).
    OBJECTIVE: To investigate the effectiveness of impaction bone grafting with morselized bone and bone paste for acetabular defects of adult Crowe type III DDH in THA.    
    METHODS: Forty cases (45 hips) of Crowe type III DDH were enrolled, including 8 males and 32 females, aged 31-68 years. All the components were reconstructed at the anatomic acetabulum combined with deepening acetabulum and putting the centre of rotation medially and distally during THA procedures. The patients were all followed up and evaluated with Harris score, limp length, displacement of the centre of rotation, cup coverage, and postoperative complications.
    RESULTS AND CONCLUSION: The average follow-up was 32.7 months. Acetabular rotation centers of all the cases were recovered (near) to normal. The incisions healed by first intention and there was no complication such as infection, dislocation, prosthesis loosening. The acetabular cup prosthesis did not displace and was covered well by bone at the last follow-up, the grafted bone particles got radiological osseointegration and the bone sclerosis zone disappeared. No radiolucent lines and screw fracture were detected. The Harris scores of affected hips at the last follow-up were significantly higher than those before surgery(P=0). The average leg length was increased (2.31±0.18) cm. The mean cup coverage was 78.1%. The postoperative horizontal and vertical distance of the hip center were shorter than those before surgery (P=0). Reconstructing the acetabulum with autogenous morselized bone graft impaction can effectively restore the acetabular coverage, maintain the stability of acetabular cup and provide better relative bone stock in THA for Crowe type III DDH in adult, and moreover, the short-term effect is satisfactory.  
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    Autologous bone marrow stromal stem cells combined with vascular pedicle iliac bone flap and tantalum rob implantation for osteonecrosis of the femoral head
    Xie Hui, Wang Zi-hua, Zhao De-wei, Huang Shi-bo, Wang Ben-jie, Wang Wei, Cui Da-ping
    2017, 21 (22):  3464-3469.  doi: 10.3969/j.issn.2095-4344.2017.22.004
    Abstract ( 352 )   PDF (1280KB) ( 199 )   Save
    BACKGROUND: There are a variety of treatments for femoral head necrosis, but their efficacy is not confirmed and unified. How to improve the differentiation ability of osteoblasts in the femoral head and improve the biomechanical support after the repair of the femoral head is an urgent problem to be solved.
    OBJECTIVE: To explore the clinical outcome of stem cells combined with vascularized iliac bone flap and tantalum rod implantation for the treatment of osteonecrosis of the femoral head (ONFH).
    METHODS: Totally 28 cases (36 hips) of non-traumatic ONFH admitted at the Zhongshan Hospital of Dalian University from January 2010 to January 2011 were enrolled. Bone marrow samples were extracted from each patient to isolate bone marrow stromal stem cells which were cultured in vitro for 2 weeks. Tantalum rod implantation with vascularized iliac bone graft was conducted to restore the femoral head shape, and then, prepared stem cell suspension were injected into the iliac bone flap and into the subchondral space of the femoral head.
    RESULTS AND CONCLUSION: All the 28 cases (36 hips) were followed up for 6-20 months (average 12 months), and their Harris hip scores and visual analogue scale scores at postoperative 6 and 12 months were significantly higher than the baseline (P < 0.05). The Harris hip score at postoperative 12 months was significantly higher than that at postoperative 6 months (P < 0.05), but there was no significant difference in the visual analogue scale scores at 6 and 12 months postoperatively (P > 0.05). At the end of 12-month follow-up, clinical outcomes were excellent in 13 hips, good in 15 hips, fair in 4 hips, and poor in 4 hips, with an excellent and good rate of 90%. These findings indicate that autologous bone marrow stromal stem cell transplantation with vascularized iliac bone flap and tantalum rob implantation is an effective method with high clinical success rate for the treatment of ONFH.
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    Preparation and evaluation of an articular cartilage extracellular matrix/human umbilical cord Wharton gel composite scaffold
    Xiao Tong-guang, Hao Chun-xiang, Jing Xiao-guang, Liu Xue-jian, Guo Gang-gang, Yang Jian-hua, Guo Quan-yi
    2017, 21 (22):  3470-3475.  doi: 10.3969/j.issn.2095-4344.2017.22.005
    Abstract ( 322 )   PDF (5840KB) ( 320 )   Save
    BACKGROUND: Soft tissue engineering mainly includes seed cells, scaffolds, cytokines and bioreactors, among which, the scaffolds are the key link in the construction of tissue-engineered cartilage.
    OBJECTIVE: To prepare an articular cartilage extracellular matrix/human umbilical cord Wharton gel porous scaffold, and to evaluate its physicochemical properties and biocompatibility.
    METHODS: The articular cartilage extracellular matrix/human umbilical cord Wharton gel porous scaffold was prepared by freeze thawing drying method using porcine articular cartilage extracellular matrix and human umbilical cord Wharton glue as raw materials. The porosity, water absorption, tissue composition and longitudinal compressive elastic modulus of the scaffold were measured and histologically stained. Rabbit chondrocytes were co-cultured with the articular cartilage extracellular matrix/human umbilical cord Wharton gel porous scaffold for 7 days. Then, scanning electron microscopy, live-dead cell staining and hematoxylin-eosin staining were performed. In addition, rabbit chondrocytes were cultured in the extract of the articular cartilage extracellular matrix/human umbilical cord Wharton gel porous scaffold and cell culture medium for 6 days, respectively; and MTT assay was used to detect cell proliferation.
    RESULTS AND CONCLUSION: The articular cartilage extracellular matrix/human umbilical cord Wharton gel porous scaffolds had a cross-section of uniform porous network structure and a vertical cross-section of the vertical tubular structure, and the pore wall was densely covered with cartilage fibers. The composite porous scaffold was positive for hematoxylin-eosin staining, safranin O staining and toluidine blue staining, and contained collagen and glycosaminoglycan ingredients. The water absorption, porosity and longitudinal compressive elastic modulus of the scaffolds were (17.418 8±0.909 0)%, (81.495 1±6.621 0)% and (2.833 3±0.456 4) kPa, respectively. After 7 days of co-culture, rabbit chondrocytes adhered to the scaffold and proliferated, and further grew into the pores of the scaffold. Moreover, the scaffold was non-toxic to the rabbit chondrocytes. To conclude, the physiochemical properties and biochemical components of articular cartilage extracellular matrix/human umbilical cord Wharton gel porous scaffolds are similar to those of natural cartilage, and the scaffold has good biocompatibility.
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    Porous Se@SiO2 nanocomposites for treatment of steroid-induced osteonecrosis of the femoral head  
    Niu Ke-run, Yang Meng-kai, Ma Chun-hui, Yu Yin-xian, Teng Song-song, Wang Qian, Yi Cheng-qing
    2017, 21 (22):  3476-3482.  doi: 10.3969/j.issn.2095-4344.2017.22.006
    Abstract ( 438 )   PDF (5865KB) ( 195 )   Save
    BACKGROUND: Steroid-induced osteonecrosis of the femoral head (SONFH) is a common bone disease characterized as high morbidity and poor prognosis, but the pathogenesis is unclear. Oxidative stress treatment is closely related to the occurrence and development of SONFH, and has tremendous potential in the treatment of SONFH, which can be realized by Nano-Se.
    OBJECTIVE: To observe the protective effect of porous Se@SiO2 nanocomposite on chondrocytes by antioxidant stress, and to further explore its mechanism of protection and treatment of SONFH.
    METHODS: (1) In vitro experiment: The rat chondrocytes were isolated, cultured and identified. Then, the chondrocytes were cultured with porous Se@SiO2 nanocomposite to suppress the production of reactive oxygen species (ROS). (2) In vivo experiment: A total of 36 rats were randomly divided into three groups. Steroid-induced group and experimental group were treated with intraperitoneal injection of lipopolysaccharide and intramuscular injection of methylprednisolone to induce SONFH models. Seven days after modeling, the experimental group was intraperitoneally injected with porous Se@SiO2 nanocomposite. No intervention was done in control group (blank control). At 8 weeks after modeling, rat bilateral femoral heads were taken for hematoxylin-eosin staining and Micro-CT scanning.
    RESULTS AND CONCLUSION: Results from the ROS detection and TUNEL apoptosis tests showed that the level of ROS in the chondrocytes was significantly reduced after intervention with Se@SiO2 (P < 0.05). Micro-CT scanning findings showed that the bone mineral density, bone volume, bone area/bone volume, trabecular number, trabecular thickness, and trabecular separation in the steroid-induced and experimental groups were significantly different from those in the control group (P < 0.05). Hematoxylin-eosin staining results showed smooth femoral head, normal bone cells, chondrocytes and trabecular bone, as well as few empty bone lacunae and fat cells in the control group, while in the steroid-induced group, there was bone trabecular fracture, fat cell hypertrophy fusion, a large number of empty bone lacunae and obvious osteonecrosis. These manifestations were significantly improved in the experimental group. To conclude, the porous Se@SiO2 nanocomposite has good antioxidative stress ability, suppresses the ROS production and exerts therapeutic effects on SONFH.
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    Tissue-engineered cartilage construction using microfibrillar collagen
    Zhou Li-bin, Xu Bing-xin, Ding Rui-ying, Han Hao-lun, Wang Gang, Li Bao-wei, Wang Hong-nan, Wu Wei
    2017, 21 (22):  3483-3487.  doi: 10.3969/j.issn.2095-4344.2017.22.007
    Abstract ( 463 )   PDF (3750KB) ( 260 )   Save
    BACKGROUND: To seek for ideal scaffold materials is still an important task for cartilage tissue engineering.
    OBJECTIVE: To investigate the application of the Avitene™ microfibrillar collagen hemostat sponge in cartilage tissue engineering.
    METHODS: Rabbit auricular cartilage was harvested via surgical operation, and primary chondrocytes were isolated and  amplified. Microfibrillar collagen hemostat sponge was cut into small bricks. The passage 2 chondrocytes were suspended and seeded onto the spongy bricks. After 1 week of in vitro culture, the constructs were then implanted into nude mice. After 8 weeks, the specimens were collected and evaluated using gross, histological and immunohistochamical observation.
    RESULTS AND CONCLUSION: During the cell seeding, the scaffold maintained its dimensions. No shrinkage was observed when the cell suspension was added. There was no considerable change in dimensions during the 1-week in vitro culture and  at 8 weeks after implantation in nude mice. At 8 weeks post-implantation, mature cartilage blocks were harvested, which were white, translucent, and flexible. Histologically, the constructs appeared to have typical mature cartilaginous tissues, with robust extracellular matrix secretion, in which the microfibrillar collagen was incompletely degraded. We conclude that the microfibrillar collagen is a favorable scaffold material for cartilage tissue engineering.
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    Preparation of silk fibroin/chitosan/nano-hydroxyapatite scaffold for sustained release of bone morphogenetic protein-2
    Huang Wen-liang, Ye Peng, Mo Gang, Tian Ren-yuan, Ma Li-kun, Ruan Shi-qiang, Xu Lin, Deng Jiang
    2017, 21 (22):  3488-3493.  doi: 10.3969/j.issn.2095-4344.2017.22.008
    Abstract ( 410 )   PDF (1186KB) ( 255 )   Save
    BACKGROUND: Bone morphogenetic protein-2 (BMP-2) is a key to bone formation and repair. However, it has some disadvantages such as easy to lose and degrade and difficult to sustain continuous effect.
    OBJECTIVE: To study the preparation and properties of silk fibroin/chitosan/nano-hydroxyapatite (SF/CS/nHA) scaffold loading BMP-2.
    METHODS: After silk degumming, dissolution and purification, 2% SF solution was obtained. BMP-2 was dissolved in 2% CS solution, and then fully mixed with equal volume of SF solution and proper amount of nHA. At last, the SF/CS/nHA scaffold loading BMP-2 was prepared using freeze-drying method as experimental group. The SF/CS/nHA scaffold was soaked in the BMP-2 solution as control group. The scaffold porosity was measured by Archimedes method, the surface morphology of the scaffold was observed by scanning electron microscope, the compressive strength was measured by universal testing machine. Scaffolds in the two groups were soaked in PBS, and the release of BMP-2 was measured by ELISA method at different time points.
    RESULTS AND CONCLUSION: (1) The scaffolds in the two groups had irregular porous structure, interconnected pores and uneven pore wall. There was no significant difference between the two groups in mean pore diameter, porosity and maximum compressive strength. (2) On the 1st day, the release rate of BMP-2 was 4.63% in the experimental group, and the release curve increased slowly. After 28 days, the release curve of BMP-2 was transferred to the plateau stage. But in the control group, the release rate of BMP-2 on the 1st day was 58.84%, and it was a significant initial burst release. The release curve increased rapidly, and was transferred to the platform stage on the 10th day. The release rate of BMP-2 release was significantly different between the two groups at days 1, 2, 4, 10 (P < 0.05). These results show that the SF/CS/nHA scaffold loading BMP-2 could sustainably and slowly release BMP-2.
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    Application of different biomaterials in the preservation of vital pulp in carious deciduous teeth: a prospective, single-center, randomized, controlled clinical trial
    Ma Xiao-hong, Xie Ni-na
    2017, 21 (22):  3494-3500.  doi: 10.3969/j.issn.2095-4344.2017.22.009
    Abstract ( 623 )   PDF (1040KB) ( 366 )   Save
    BACKGROUND: The success of the preservation of vital pulp in carious deciduous teeth depends not only on determining the health status of the pulp, but also on selecting the most suitable pulp capping agent. At present, the commonly used pulp capping agent materials contain calcium hydroxide preparation and mineral trioxide aggregate (MTA). Recently, new biomaterials, such as Bioaggregate, Biodentine, and TheraCal, with good biocompatibility and good edge sealing, have been developed and extensively used.
    OBJECTIVE: To compare the efficacies of MTA, calcium hydroxide preparation, Biodentine and TheraCal LC that are commonly used in pediatric dentistry in the preservation of vital pulp in carious deciduous teeth.
    METHODS: This prospective, single-center, randomized controlled clinical trial will be conducted in Chengdu Maternal and Child Center, China. Children with deep caries of deciduous teeth, who will be scheduled to undergo indirect pulp capping, direct pulp capping, and vital pulpotomy, will be selected and randomized into four groups according to pulp capping agents: MTA group, calcium hydroxide group, Biodentine group and TheraCal group. Patients will receive return visit at postoperative 3, 6 and 12 months during follow-up. By using X-ray, we will observe and compare the speed and quality of the formation of the dentin bridge with different biomaterials, and assess the reason for the failure of treatment. This trial was registered in ClinicalTrials.gov identifier: NCT03220360, on July 14, 2017. The study protocol has been approved by the Ethics Committee of Chengdu Maternal and Child Center, China (approval number: 20170506). All protocols will be performed in accordance with the Ethical Principles for Medical Research Involving Human Subjects in the Declaration of Helsinki. Written informed consent will be provided by each patient and their family members after they indicated that they fully understood the treatment plan.
    RESULTS AND CONCLUSION: This study will compare the efficacies of various biomaterials in the preservation of vital pulp in carious deciduous teeth. New materials Biodentine and TheraCal will be selected in classical technique to verify their efficacies and explore their superiorities. Classical materials calcium hydroxide and MTA will be selected as controls, which will be separately used in indirect pulp capping, direct pulp capping, and vital pulpotomy to provide reliable choices for clinicians.
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    Three-dimensional finite element analysis on the stress of mandibular first molar restored with different locations and numbers of gold alloy posts and cores
    Liu Tao, Geng Hai-xia
    2017, 21 (22):  3501-3506.  doi: 10.3969/j.issn.2095-4344.2017.22.010
    Abstract ( 357 )   PDF (1436KB) ( 318 )   Save
    BACKGROUND: The design of post and core of the molar is affected by various factors, including the effect of the number of posts on the retention force and the effect of the number of posts on the dentin stress and distribution.
    OBJECTIVE: To make a mechanical analysis on the three-dimensional finite element models of the mandibular first molar defect restored with different numbers and locations of gold alloy posts, cores and all-ceramic crown.
    METHODS: Cone-beam CT based three-dimensional finite element models of post and core restored first mandibular molars were established, with seven different post designs. According to the numbers and location of gold alloy post inserted into root canal, a single post was placed at the mesial buccal root in group A, a single post at the mesial tongue root in group B, a single post at the distal root in group C, two posts at the mesial buccal root and the distal root in group D, two posts at the mesial buccal root and mesial tongue root in group E, two posts at the mesial tongue root and the distal root in group F, one post respectively at the mesial buccal root, mesial tongue root and distal root in group G. The von Mises criterion was applied for comparing the maximum von Mises stress value of dentin and stress concentration areas in the seven models which restored with golden alloy posts and cores with all-ceramic crown under the maximum (600 N), vertical (225 N), inclined (225 N) and horizontal (225 N) loads.
    RESULTS AND CONCLUSION: Under vertical, inclined and horizontal direct loads, the maximum stresses on the remaining dentin in group C were significantly lowest, compared with the groups A and B. The maximum stresses on the remaining dentin changed irregularly with the variation of the numbers and location of posts, when the mandibular first molar defect was restored with all-ceramic crown with gold alloy posts and cores. Under the horizontal load, the maximum Von Mises stress value of the dentin increased remarkably. Under the horizontal load, the maximum stresses on the remaining dentin in group E were the highest. To conclude, the numbers and location of posts and cores have influence on magnitude and distribution of stress, when the mandibular first molar defect is restored with all-ceramic crown with gold alloy post and core.
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    Effects of different post-core materials with different angles on fracture resistant ability of the maxillary central incisor
    Qian Yu-mei, Zhong Qun, Chen Shuang, Tie Si-jiu
    2017, 21 (22):  3507-3512.  doi: 10.3969/j.issn.2095-4344.2017.22.011
    Abstract ( 346 )   PDF (2245KB) ( 168 )   Save
    BACKGROUND: In clinical practice, there are some patients with labial inclined anterior teeth which influence their appearance, but they refuse orthodontic treatment because of many factors such as long-term treatment. Alternatively, these patients can receive aesthetics restoration with re-directional post-core and crown.
    OBJECTIVE: To investigate the influence of three kinds of post-core materials on fracture resistant ability of labial inclined maxillary central incisor with different changed angles.
    METHODS: Seventy-five maxillary central incisors were randomly divided into three groups: group I was restored with Co-Cr post-core and porcelain-fused-to-metal (PFM) crown, group II was restored with 50% gold alloy post-core and PFM crown, group III was restored with everStick fiber post and composite resin core and PFM crowns. Each group then was divided into five subgroups based on angles between the post-core and long axis of the tooth (0°, 10°, 20°, 30°, 40°). All specimens were embedded in acrylic resin and fixed in electronic universal testing machine. Force was loaded to each specimen until fracture occurred, and the maximum load values of fracture and the fracture mode were recorded.
    RESULTS AND CONCLUSION: The fracture resistance of group III was superior to groups I and II (P < 0. 05), but there was no significant difference between group I and group II (P > 0.05). The maximum load value of the three groups decreased as the changed angle increased. The fracture of group III mostly appeared on the 1/3 of the root neck, while the fracture of groups I and II mostly appeared on the 1/3 of root central or the 1/3 of the root neck. So, the fracture resistance and fracture mode of central incisor under changed angles restored with everStick fiber post were superior to that with cast metal post-core. During re-directional restoration of labial inclined maxillary anterior teeth, everStick fiber post is recommended as a better choice to reduce the risk of catastrophic fractures. Also it suggests that excessive changed angle should be avoided to prevent root fracture.
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    Correlation between complete denture relines and serum bone turnover markers in elderly edentulous patients with osteoporosis
    Yu Tian-hao, Jia Xing-ya, Xue Yan-qing, Zhan De-song, Yan Xu
    2017, 21 (22):  3513-3518.  doi: 10.3969/j.issn.2095-4344.2017.22.012
    Abstract ( 366 )   PDF (1097KB) ( 194 )   Save
    BACKGROUND: The residual alveolar ridge in edentulous patients with osteoporosis always presents with a poor shape, which increases the difficulty in complete denture restoration. Until now, there are no predictors for residual alveolar ridge resorption or guidelines on the frequency of denture relines.
    OBJECTIVE: To investigate the correlation between the frequency of complete denture relines and serum bone turnover markers, osteocalcin (OC) and cross-linked carboxy-terminal telopeptide of type I collagen (CTX), in elderly edentulous patients with osteoporosis, in order to provide reference for complete denture repair.
    METHODS: According to inclusion criteria, 50 elderly edentulous patients with osteoporosis who had complete dentures were recruited in the study randomly. The frequency of complete denture relines was surveyed by related questionnaire and medical record, and the serum OC and CTX levels were detected by electrochemiluminescence immunoassay. Related data were analyzed statistically via Pearson correlation analysis.
    RESULTS AND CONCLUSION: It showed a strong positive correlation between the frequency of complete denture relines and the serum OC level (r=0.517, P < 0.01). No significant correlation between relines frequency and the serum CTX level was observed (r=0.278, P=0.051 > 0.05), but it showed a similar tendency between them. These findings indicate that to detect the levels of serum bone turnover markers may be conducive to evaluating curative effect of complete dentures in elderly edentulous patients with osteoporosis as well as to making subsequent diagnostic and therapeutic strategies.
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    Effect of ultraviolet rays on the re-activation of the physicochemical properties and bioactivity of aging titanium surface
    Lu Hai-bin, Wan Lei, Zhang Xue-yang, Rong Ming-deng, Zhou Lei
    2017, 21 (22):  3519-3524.  doi: 10.3969/j.issn.2095-4344.2017.22.013
    Abstract ( 442 )   PDF (2585KB) ( 191 )   Save
    BACKGROUND: The physicochemical properties and bioactivity of titanium surface will degrade with time because of the aging phenomenon, affecting the efficiency of implant-bone osseointegration. Therefore, the re-activation of the implant surface physicochencical properties and bioactivity is important.
    OBJECTIVE: To investigate the re-activation effect of ultraviolet rays on aging titanium surface.
    METHODS: Sand-blasted and acid-etched titanium discs were divided into three groups randomly: Group A was new titanium surface, Group B was stored in a sealed container for 4 weeks, Group C was treated with ultraviolet rays for 15 minutes after stored in the sealed container for 4 weeks. The surface roughness, elemental composition and surface energy of the titanium surface were examined by optical profilometer, X-ray photoelectron spectroscopy and contact angle measuring device, respectively. The bioactivity of the titanium surface was examined by cell culture experiments. MG63 osteoblast-like cells were cultured on the different titanium surfaces. After 30 minutes, 1, 2, 4 hours of incubation, the cells were strained with Hoechst33342 fluorescence, and initial attachment of cells was evaluated by measuring the amount of cells attached to the titanium surface. The proliferation of cells was quantified in terms of cell density at 1 and 3 culture days using tetrazolium salt (MTS)-based colorimetry.
    RESULTS AND CONCLUSION: There was no obvious difference in the surface roughness of the three groups, and ultraviolet treatment did not change the surface morphology of titanium surface. X-ray photoelectron spectroscopy showed that the C element content of group A and group C was lower than that of group B (P < 0.05), and the content of Ti, O, N elements was significantly higher than that of group B (P < 0.05). No difference in the surface element composition between group A and group C was found. Both of the surface contact angles of group A and group C were 0o, but in group B, the value was 115°. The number of initially attached cells of group A and group C was significantly higher than that of group B after incubated 30 minutes, 1, 2 and 4 hours (P < 0.05), and no difference between group A and group C was found. The proliferation of cells of group A and group C was significantly higher than that of group B after incubated 1 and 3 days (P < 0.05), but no difference between group A and group C was found. In conclusion, ultraviolet rays show good effects on the re-activation of the aging titanium surface, which can reduce hydrocarbon contamination and recover the high surface energy to increase cell adhesion and proliferation.
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    Anterior tooth movement of micro-implant-double slot lingual bracket system with Heat Induction Typodont System
    Wu Xiu-ping, Hee MoonKyung, Li Bing, Jing Xuan, Li Shi-feng
    2017, 21 (22):  3525-3530.  doi: 10.3969/j.issn.2095-4344.2017.22.014
    Abstract ( 503 )   PDF (1200KB) ( 233 )   Save
    BACKGROUND: Heat Induction Typodont System (HITS) and Double-Slot Lingual Bracket System are patented products of the research group. It is very important to explore a good control of anterior tooth torque on the micro-implant-double-slot lingual bracket system.
    OBJECTIVE: To provide the experimental basis for force system applied for controlling the anterior tooth torque in lingual orthodontics through Typodont experiment based on the HITS.
    METHODS: Sixteen Class II1 maxillary Typodont models without first premolar were made. Micro-implants were implanted in the lingual region of posterior teeth and labial region of anterior teeth. The direction of the retracting force was adjusted by changing the position of the lingual micro-implant (with a distance of 4, 8 mm from the alveolar crest) and the length of the hook (4, 8 mm). And lingual retracting force (150, 300 g) and labial intruding force (50, 100 g) were loaded. The tooth movement by HITS was simulated and the models were scanned before and after force loading. Then the three-dimensional images were reconstructed by Mimics 17.0. Factorial variance analysis was adopted to compare the anterior movement changes under different loading modes.
    RESULTS AND CONCLUSION: When the length of the hook was 4 mm/8 mm and the lingual micro-implant was       6 mm/10 mm from the alveolar crest, the displacement difference between the incisal edge and the root of the anterior teeth was smaller than other groups. The optimal mechanics was 150 g for the lingual retracting force and 100 g for the labial intruding force. It could provide a satisfactory control to the anterior teeth torque when retracting force and labial intruding force were loaded at the same time during the space closing phase of lingual treatment. This study based on HITS provided a scientific basis for the clinical application of micro-implant-double-slot lingual bracket system in space closing phase.
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    Improving angiogenesis by collagen sponge carrying human adipose-derived stem cells
    Xue Jing-xian, Chen Xu, Xu Yan-lei, Ren Wei-ye, Li Yan, Zhang Yu-xuan, Yao Chang
    2017, 21 (22):  3531-3535.  doi: 10.3969/j.issn.2095-4344.2017.22.015
    Abstract ( 335 )   PDF (1648KB) ( 166 )   Save
    BACKGROUND: Studies have found that adipose-derived stem cells (ADSCs)/collagen complexes can promote the ADSCs differentiation and maturation into mature adipocytes and promote angiogenesis.
    OBJECTIVE: To explore the biological properties of the ADSCs/collagen sponge composite material and to detect its effect on angiogenesis.
    METHODS: (1) ADSCs were cultured on collagen sponge (experimental group) or cultured alone (control group). After 24 hours of culture, cell adhesive rate of ADSCs was determined with flow cytometry. After 2, 4, 6 days of culture, cell proliferation and level of vascular endothelial growth factor (VEGF) in the culture medium were detected. (2) Chick embryo chorioallantoic membranes were exposed and incubated for 7 days and then divided into four groups: 0.2 mL of sterile PBS was added in the blank group, 0.2 mL of 2×108/L passage 3 ADSCs suspension was added in the ADSCs group, collagen sponge was added in the collagen sponge group, and collagen sponge with 0.2 mL of 2×108/L passage 3 ADSCs suspension was added in the composite group. After 7 days of incubation, the microvessel count around the chorioallantoic membrane was measured.
    RESULTS AND CONCLUSION: (1) The cell adhesive rate of ADSCs to collagen sponge reached to (93.04±0.67)%. (2) The absorbance value (at 6 days of culture) and level of VEGF (at 4 and 6 days of culture) in the experimental group were significantly higher than those in the control group (P < 0.01 or P < 0.05). (3) Compared with the blank group, the number of microvessels was significantly higher in the ADSCs, collagen sponge and composite groups (P < 0.05). Moreover, higher amount of microvessels were found in the composite group than the ADSCs and collagen sponge groups (P < 0.05). To conclude, ADSCs can adhere well to the collagen sponge with good biocompatibility and their combined use can improve angiogenesis further by enhancing cell proliferation and VEGF secretion of ADSCs.
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    Titanium core/bone morphogenetic protein composite materials used to repair alveolar bone defects after immediate implant placement
    Yang Yu-peng, Zhao Hai-jing, Gu Jian-qi, Cheng Feng-xia, Zheng Yao, Li Juan, Hao Wei, Wang Xi-xi, Wu Yong-sheng
    2017, 21 (22):  3536-3540.  doi: 10.3969/j.issn.2095-4344.2017.22.016
    Abstract ( 345 )   PDF (5244KB) ( 171 )   Save
    BACKGROUND: Now experimental and clinical research on suitable bone substitutes for alveolar bone defects after dental implantation is an issue of concern.
    OBJECTIVE: To study the therapeutic effect of titanium core/bone morphogenetic protein (BMP) composite material on alveolar bone defects after immediate implant placement.
    METHODS: Twenty-four New Zealand rabbits were randomly assigned into normal group (no intervention), experimental group or control group. Animal models of bone femoral greater trochanter defect were made in the experimental and control groups. Dental implant and titanium core/BMP composite material were implanted in the experimental group, while dental implant and titanium core were implanted in the control group. Percentage of CD4+, CD8+ T lymphocytes, natural killer cell activity and interleukin 2 level were detected at postoperative 4 weeks; bone mineral density and osteogenesis around the implant were detected at postoperative 16 weeks through X-ray and histological examinations.
    RESULTS AND CONCLUSION: X-ray results showed that the bone mineral density in the experimental group was significantly higher than that in the control group (P < 0.05). Histological results showed that in the experimental group, different degrees of cell lysis around the composite, more bone cells and bone matrices were found, implant-bone osseointegration formed well, and red-dyed mature bone tissues were detective inside the implant. Compared with the experimental group, lower number of bone cells and fibrocytes were found in the control group. Additionally, the percentage of CD4+ and CD8+ T lymphocytes, natural killer cell activity and interleukin 2 level in the experimental group were significantly lower than those in the control group (P < 0.05). To conclude, the titanium core/BMP composite material can effectively repair alveolar bone defects after immediate implant placement to guide the growth of bone cells.
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    Biocompatibility of modified nano-hydroxyapatite/polyvinyl alcohol porous composite hydrogel as an artificial corneal material
    Du Qian, Du Chen, Jin Gui-yu, Tian Hua
    2017, 21 (22):  3541-3546.  doi: 10.3969/j.issn.2095-4344.2017.22.017
    Abstract ( 483 )   PDF (6122KB) ( 313 )   Save
    BACKGROUND: How to improve the stability of artificial cornea in the host and reduce the complications is the current key issues to be solved. Therefore, looking for an ideal biocompatible scaffold material is still the focus of the study.
    OBJECTIVE: To explore the biocompatibility of nano-hydroxyapatite (nHA)/polyvinyl alcohol (PVA) porous composite hydrogel and pure PVA hydrogel as artificial corneal materials.
    METHODS: Inverted microscope was used to observe cell growth of rabbit corneal stromal fibroblasts when cultured with nHA/PVA composite hydrogel extract or PVA extract for 48 hours. MTT method was used to detect the relative proliferation rate of rabbit corneal stromal fibroblasts cultured with nHA/PVA composite hydrogel extract or PVA extract. Systemic toxicity, allergies, pyrogen reaction and deaths were observed in New Zealand white rabbits at 48 hours after artificial corneal implantation. ELISA and hematoxylin-eosin staining were used to detect changes in serum inflammatory factors at 4 weeks after artificial corneal implantation. Slit-lamp examination was performed to observe corneal or conjunctival hyperemia/edema and corneal neovascularization at 1-4 weeks after corneal implantation. Corneal neovascularization time and neovascularization area were detected after the two materials were implanted.
    RESULTS AND CONCLUSION: The cells were sparse and grew slowly at 48 hours after culture in nHA/PVA composite hydrogel or PVA extract as compared with the blank control group. The cell growth in the nHA/PVA composite hydrogel group was better than that in the PVA group. The relative cell proliferation rate was significantly decreased at different time after culture in nHA/PVA composite hydrogel or PVA extract compared with the blank control group (P < 0.05), and the relative cell proliferation rate in the nHA/PVA composite hydrogel group was significantly higher than that in the PVA group (P < 0.05). There were two rabbits appearing to have allergic reaction, but no one presenting with pyrogen reaction and death in the nHA/PVA composite hydrogel group; and there were two rabbits appearing to have allergic reaction, and two appearing to have pyrogen reaction, but no death in the PVA group at 48 hours after implantation. The inflammatory factor levels were increased significantly in the nHA/PVA composite hydrogel group and PVA group compared with the control group (P < 0.05), and inflammatory infiltration was milder in the nHA/PVA composite hydrogel group than the PVA group at 4 weeks after implantation (P < 0.05). Corneal neovascularization appeared later in the nHA/PVA composite hydrogel group than the PVA group, and the neovascularization area was also smaller in the nHA/PVA composite hydrogel group than the PVA group (P < 0.05). Taken together, the biocompatibility of nHA/PVA composite hydrogel is superior to that of pure PVA when they are used as artificial cornea materials, which provides a scientific basis for artificial cornea material innovation and extensive clinical application.
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    In vivo biocompatibility of nano-hydroxyapatite/polyphenylene sulfide composites
    Fan Ke-xia, Ma Yuan, Yang Wei-zhong, Yu Si-xun, Sun Zhi-yong, Xia Xun, Yang Li-bin, Guo Heng, Kuang Yong-qin, Gu Jian-wen
    2017, 21 (22):  3547-3554.  doi: 10.3969/j.issn.2095-4344.2017.22.018
    Abstract ( 542 )   PDF (5968KB) ( 227 )   Save
    BACKGROUND: There is a lack of the research concerning the biocompatibility of nano-hydroxyapatite/polyphenylene sulfide (nHA/PPS) composites.
    OBJECTIVE: To evaluate the in vivo biocompatibility of nHA/PPS composites based on the completed research in vitro.
    METHODS: Systemic toxicity test: Sprague-Dawley rats were given the intraperitoneal injection of nHA/PPS extract or normal saline. The general situation, body mass and the histological changes of the liver and kidney were observed at 72 hours after injection. Delayed type hypersensitivity test: nHA/PPS extract or normal saline was injected subcutaneously into the back of the rats. Afterwards, skin irritation symptoms were observed at 72 hours. Local reaction experiment: nHA/PPS composites and polyethylene were respectively implanted into the back of the rats. The pathological changes of the implanted materials and their surrounding tissues were observed at 15 and 30 days after implantation.
    RESULTS AND CONCLUSION: (1) The rats were in good situation after nHA/PPS injection; the body mass increased steadily, which showed no significant difference from the control group (P < 0.05); the morphology and color of the liver and kidney were normal, and the systemic toxicity of the composite materials was normal according to the degree of toxicity classification. (2) There were no obvious skin irritation symptoms after the subcutaneous injection of nHA/PPS composites, and the primary irritation index was less than 0.4, suggesting a low hypersensitivity. After implantation of nHA/PPS composites, there was no obvious degradation, absorption and rejection, and both the degree of inflammatory reaction (15 days ≤ level III, 30 days ≤ level II) and the thickness of fibrous capsule (15 days ≤ level III, 30 days ≤ level II) revealed the good biocompatibility of the composites. These results suggest that the nHA/PPS composites hold an excellent biocompatibility in vivo.
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    Aspirin effects on MG-63 cell proliferation on different modified titanium surfaces under fluid shear stress
    Liang Zhong-lang, Liu Chang-hong, Li Shi-yi, Yang Xiao-yu
    2017, 21 (22):  3555-3560.  doi: 10.3969/j.issn.2095-4344.2017.22.019
    Abstract ( 393 )   PDF (1163KB) ( 166 )   Save
    BACKGROUND: Recent research has shown that the proper concentration of aspirin can increase the proliferation and osteogenic ability of MG-63 cells.
    OBJECTIVE: To explore the effects of different concentrations of aspirin on osteoblast proliferation on the implant-cell interface under fluid shear stress.
    METHODS: (1) MG-63 cells were cultured in low-glucose DMEM containing 10% fetal bovine serum and different concentrations of aspirin (0, 0.023, 0.046, 0.0625, 0.125, 0.25, 0.5, 1.0, 2.0, 4.0 mmol/L) for 1-7 days. Then cell proliferation was detected using MTS method. (2) MG-63 cells were cultured on three different surfaces: glass slide, PT titanium surface and SLA titanium surface. After 3 days of culture with aspirin at a concentration of 0 or 0.5 mmol/L, the cells were subjected to fluid shear stress. MTS test was applied to estimate the proliferation of MG-63 cells at 0, 0.5, 1, 2, 4 hours after stress application.
    RESULTS AND CONCLUSION: (1) After 1-3 days of culture, 0.023, 0.046, 0.5 mmol/L aspirin promoted the proliferation of MG-63 cells, while after 1-7 days of culture, 1, 2, 4 mmol/L aspirin inhibited the proliferation of MG-63 cells. (2) Under the fluid shear stress, aspirin showed significant effects on the cell proliferation as confirmed by one-way analysis of variance (F=8.349, P=0.004), and 0.5 mmol/L aspirin inhibited the cellular proliferation of MG-63 cells. However, surface modification and stress loading time showed no significant effects on the cell proliferation (F=2.826, P=0.064; F=0.893, P=0.406). (3) Under the fluid shear stress, surface modification showed no significant effect on the cell proliferation of MG-63 cells cultured with 0.5 mmol/L aspirin (F=1.803, P=0.171). Under the fluid shear stress, 0.5 mmol/L aspirin significantly inhibited the proliferation of MG-63 cells on the glass slide (P=0.003), while PT and SLA titanium surfaces showed on inhibitory effect on the cell proliferation (P=0.891, P=0.051). The present results demonstrate that the cell proliferation of MG-63 is related with aspirin in a concentration-dependent manner. In addition, different titanium surfaces may decrease the sensitivity of MG-63 cell proliferation to aspirin.
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    Hemostatic effect of carboxymethyl chitosan and its biosecurity properties
    Liu Xia, Zhao Gui-zhi, Wang Yu-ji, Cai Ting-ting, Zhu Wan-ping
    2017, 21 (22):  3561-3566.  doi: 10.3969/j.issn.2095-4344.2017.22.020
    Abstract ( 591 )   PDF (1152KB) ( 212 )   Save
    BACKGROUND: Carboxymethyl chitosan (CMCS), a chitin derivative, has a good application performance that makes it become a safe and effective hemostatic material.  
    OBJECTIVE: To determine the hemostatic effect of CMCS and its biosecurity properties.
    METHODS: (1) CMCS powder was scattered on the caudal vein and liver wounds of Sprague-Dawley rats, and the hemostatic time was recorded as experimental group, while the time for natural haemostasis of the wound was recorded as control group. (2) CMCS powder was scattered on the tail, femoral artery and liver wounds of ICR mice, and the hemostatic time was recorded as experimental group, while the time for natural haemostasis of the wound was recorded as control group. (3) CMCS, Sodium dodecyl sulfate solution and distilled water were respectively applied on the skin of albino rabbits in a skin irritation test. (4) A delayed-type hypersensitivity test of CMCS was carried out by intradermal injection of CMCS in guinea pigs. (5) An intradermal irritation test was carried out by subcutaneous injection of normal saline containing CMCS and normal saline, respectively. Another intradermal irritation test was carried out by subcutaneous injection of the supernatant of CMCS olive oil extract and olive oil, respectively.
    RESULTS AND CONCLUSION: (1) Compared with the control group, the hemostatic time for caudal vein and liver wounds were significantly shortened in the Sprague-Dawley rats in the experimental group (P < 0.01). (2) Compared with the control group, the time of hemostasis on the tail, femoral artery and liver wounds was significantly shortened in the ICR mice in the experimental group (P < 0.05 or P < 0.01). (3) The CMCS had no irritation to the skin of albino rabbits and no allergic reaction to the skin of guinea pigs. To conclude, the CMCS has good hemostatic effect on the wound in Sprague-Dawley rats and ICR mice, and has no skin irritation, allergic reactions and intradermal irritation reactions in albino rabbits and guinea pigs, which is a relatively safe hemostatic material.
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    A review on nano-materials as joint replacement implants
    Wang Lin, Chen Dan-ying, Zhang Zhi-yu, Zhang Hang-zhou
    2017, 21 (22):  3567-3575.  doi: 10.3969/j.issn.2095-4344.2017.22.021
    Abstract ( 300 )   PDF (827KB) ( 252 )   Save
    BACKGROUND: Implant related problems such as loosening, dislocation and infection often come along with joint replacement. Nanotechnology provides a new insight into the preparation of joint replacement implants.
    OBJECTIVE: To elaborate the research progress of nanotechnology in improving joint replacement implants.
    METHODS: The first author used the computer to retrieve PubMed databases using the key words of “joint replacement, artificial implant, nanotechnology, nano-materials, nanoscales, biocompatibility” in English, to find relevant literature on nanotechnology and joint replacement implants. All data were primarily screened to exclude repeated and irrelevant articles, and finally 51 articles related to the study were retained.
    RESULTS AND CONCLUSION: Through reviewing these 51 articles, we make a detailed introduction about some of the biological responses that occur with nano-materials, and some of the biocompatibility problems that have been raised in relation to materials, as well as the ways that have been employed to improve biocompatibility of nano structured materials. But the long-term effect of nanotechnology on the human body is still worthy of further research in medicine or related fields. 
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    Bioceramics in bone tissue engineering
    Lu Chen-pei, Wang Xu-dong, Shen Guo-fang
    2017, 21 (22):  3576-3582.  doi: 10.3969/j.issn.2095-4344.2017.22.022
    Abstract ( 671 )   PDF (1163KB) ( 294 )   Save

    BACKGROUND: Bioceramic has similar components compared to human bone tissue and it has shown good ostoconductivity both in vitro and in vivo. Meanwhile, it is biocompatible. So, bioceramics is considered as one of the most promising materials which can be applied to bone tissue engineering.
    OBJECTIVE: To summarize the properties of bioceramics and the research progress in experimental studies and clinical applications.
    METHODS: PubMed was searched for relevant articles published during 2000 to 2016 with the key words of “bioceramics, hydroxylapatite, calcium phosphate, bioglass, bone tissue engineering” in English.
    RESULTS AND CONCLUSION: Bioceramic materials can be divided into two categories: calcium phosphates and bioactive glass. Calcium phosphates have good biocompatibility and osteoconductivity, while the mechanical property is not so satisfying. Bioactive glass is biocompatible and beneficial to the expression of some osteogenic genes, but it is brittle and weak. Some kinds of bioceramics have already been applied to clinical practice. In recent years, calcium phosphates have also been used as coated materials to improve the properties of tissue-engineered scaffolds. Bioceramics combined with synthetic polymers, shows better mechanical performance and biodegradation. Even so, it still has plenty of problems and challenges as a widely used bone repair material in clinical practice.

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    Advances in titanium bone implants made by rapid prototyping technology
    Wei Hong-pu, Wang Xu-dong
    2017, 21 (22):  3583-3588.  doi: 10.3969/j.issn.2095-4344.2017.22.023
    Abstract ( 334 )   PDF (845KB) ( 237 )   Save
    BACKGROUND: In recent years, rapid prototyping has provided new options for the manufacture of customized titanium implants.
    OBJECTIVE: To review the optimization of titanium bone implants made by rapid prototyping, and assess its clinical value.
    METHODS: A computer-based retrieval of PubMed database and CNKI was performed for relevant articles by using the keywords of “rapid prototype, 3D printing, additive manufacture, titanium, custom-made, implant” both in English and Chinese. These articles were analyzed from two aspects: the performance optimization and the clinical application of titanium bone implants produced by rapid prototyping.
    RESULTS AND CONCLUSION: Rapid prototyping technology enables the production of customized bone implants, and biological properties of the implants can be varied through the introduction of porosity and Morphological changes of the implant. In combination with surface treatment technology, such as coating technique, the biological performance of the implants can be further optimized. Therefore, the rapid prototyping technology can be used to create customized titanium bone implants with excellent mechanical and biological properties. The titanium bone implants made by rapid prototyping have great prospect in the clinical practice.
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    3D bioprinting of tissues and organs and its application in oral medicine
    Lin Yu-heng, Wang Xu-dong, Shen Guo-fang
    2017, 21 (22):  3589-3594.  doi: 10.3969/j.issn.2095-4344.2017.22.024
    Abstract ( 405 )   PDF (1221KB) ( 247 )   Save
    BACKGROUND: 3D bioprinting has been used to print a variety of tissues including skin, vascular tissues, liver,cartilage, cardiac tissues, ear, and adipose tissues.
    OBJECTIVE: To review the application of 3D bioprinting technology in printing tissues or organs and its research progress in oral medicine.
    METHODS: A computer-based retrieval of PubMed and CNKI was performed to search articles concerning the application of 3D bioprinting technology in printing tissues, organs and stomatology which were published from 2006 to 2016, using the keywords of “3D bioprinting, 3D pinting, organs, tissues, tissue engineering, stomatology, oral, cranio-maxillofacial” in English and Chinese, respectively.
    RESULTS AND CONCLUSION: Direct cell-bioprinting is still in its early stage, even though 3D bioprinting has been applied to print various tissues such as skin, vascular tissues, liver, cartilage and cardiac tissues, etc. Although additive manufacturing technology has been widely used for printing different scaffolds of tissues and organs nowadays, there are no successful bioprinted tissues with biological functions in clinical practice. Even in oral medicine, most of the studies still remain in the stage of printing biological scaffolds. It is a long way to solve the problems such as source of cells, materials of biological scaffolds and types of extracellular matrix in the future, due to the complexity of human organism structure and the function expression of various tissues and organs. 
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    Non-biodegradable and biodegradable long-term subdermal contraceptive implants: advances in theoretical research and application
    Zhang Jin-zhe, Zhou Qun-hua, Yang Li-qun, Zhang Wei, Li Jian-xin, Jin Ying, Yi Dong-xu
    2017, 21 (22):  3595-3601.  doi: 10.3969/j.issn.2095-4344.2017.22.025
    Abstract ( 453 )   PDF (1454KB) ( 268 )   Save
    BACKGROUND: Subdermal contraceptive implants as a novel contraceptive method have been extensively used worldwide.
    OBJECTIVE: To review the research progress in the non-biodegradable and biodegradable long-term subdermal contraceptive implants and to explore their advantages and disadvantages.
    METHODS: A computer-based search of CNKI, Wanfang, and PubMed (1967-2015) was performed by the first author for relevant articles, using the key words of “contraceptive implants, non-biodegradable, biodegradable” in Chinese and English, respectively. Initially 240 articles were retrieved, and finally 70 articles were included in result analysis.
    RESULTS AND CONCLUSION: Long-term subdermal contraceptive implants that pass through the local capillaries into the blood circulation system can avoid the gastrointestinal absorption, improve the bioavailability of drugs, and reduce adverse drug reactions. According to the performance, there are two kinds of drug carriers, non-biodegradable and biodegradable. Although non-biodegradable implants have been widely used and the contraceptive effect is excellent, the implants must be removed surgically because they cannot be absorbed or metabolized in the body. Significant efforts have been devoted to developing biodegradable implants because they can degrade at the end of use. However, the utility of some biodegradable polymers as drug carriers in implantable applications has been hampered by their shortcomings, and further study on alternative materials is urgently required. 
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    Effect of combination of acellular nerve grafts and stem cells for sciatic nerve regeneration: a Meta-analysis
    Xiang Fei-fan, Yang Yun-kang, Tan Xiao-qi, Wei Dai-qing, Yang Kun, Sun Yuan-lin, Zhou Ju
    2017, 21 (22):  3602-3608.  doi: 10.3969/j.issn.2095-4344.2017.22.026
    Abstract ( 296 )   PDF (1995KB) ( 258 )   Save
    BACKGROUND: Acellular nerve scaffolds have the three-dimensional structure of natural nerves and low immunogenicity, but their effect on long nerve defects is still not ideal. Therefore, it is necessary to construct tissue- engineered nerve using acellular nerve and seed cells in order to improve the therapeutic effect.
    OBJECTIVE: To systemically review the efficacy of combination of acellular nerve grafts (ANGs) and mesenchymal stem cells (MSCs) or Schwann cells (SCs) transplantation in the treatment of sciatic nerve defects in a rat model.
    METHODS: Randomized controlled trials (RCTs) about the effects of combination of ANGs and MSCs or SCs transplantation for sciatic nerve defects in rats were searched in PubMed, The Cochrane Library, EMbase, CNKI, WanFang and VIP from inception to July 2016. Three reviewers independently screened literature according to the inclusion and exclusion criteria, extracted data, and assessed the risk of bias of included studies. Then, a Meta-analysis was performed using Review Manger5.3 software.
    RESULTS AND CONCLUSION: A total of 10 RCTs involving 252 rats were included. The results of meta-analysis showed that: compared with the control group (simple acellular nerve scaffold group), the sciatic functional index (SFI) of the combined group (combination of ANGs and MSCs or SCs transplantation) were superior at 2 weeks [SMD=2.73, 95% CI (1.92, 3.45), P < 0.000 01], 4 weeks [SMD=4.57, 95% CI (3.43, 5.70), P < 0.000 01], 6 weeks [SMD=1.62, 95% CI (0.18,3.06), P=0.03], 8 weeks [SMD=4.90, 95% CI (2.96, 6.84), P < 0.000 01] after surgery. The nerve conduction velocity [SMD=1.39, 95% CI (0.99, 1.78), P < 0.000 01), latency period (MD=-0.98, 95% CI (-1.19, -0.76), P < 0.000 01], and amplitude [SMD=1.23, 95% CI (0.62, 1.85), P < 0.000 1] were superior at 12 weeks after surgery. The myelin sheath thickness was superior at 8 weeks [MD=0.14, 95% CI (0.07, 0.21), P < 0.000 1], 12 weeks [SMD=1.85, 95% CI (1.63, 2.08), P < 0.000 01] and the number of myelinated nerve fibers were superior at 12 weeks [SMD=3.59, 95%CI (2.63, 4.55), P < 0.000 01] after surgery. The gastrocnemius wet weight was superior at 8 weeks after surgery [SMD=4.22, 95% CI (2.40, 6.03), P < 0.000 01]. Current evidence indicates that the combination of ANGs and MSCs or SCs can promote the regeneration and functional recovery of the peripheral nerve. Due to the limited quality of the included studies, the above conclusion should be verified by conducting high-quality and large-scale RCTs.
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