新型壳聚糖基温敏凝胶膜引导骨再生性能的体外实验研究

目的制备负载釉基质蛋白（enamel matrix proteins,EMPs）的壳聚糖/β甘油磷酸钠(chitosan/β-glycerophosphate salt,CS/β-GP)温敏凝胶膜,探讨其体外引导骨再生的能力。方法利用CS/β-GP体系的温敏相转变特性,制备新型生物膜并添加牛血清白蛋白（bovine serum albumin,BSA）,利用蛋白浓度测定试剂盒（加强型）检测不同时点的蛋白释放浓度,绘制蛋白缓释曲线。添加EMPs的CS/β-GP（1.0 g）复合膜作为A组; 单纯CS/β-GP（1.0 g）复合膜作为B组;同时,设空白对照组即C组,分别与ST2细胞共培养。检测膜的理化性能, MTT法检测复合膜的生物相容性, PNPP法检测碱性磷酸酶（alkaline phosphatase, ALP）的活性。采用SPSS16.0软件包对数据进行统计学分析。结果不同浓度的复合膜可缓慢释放蛋白12 d以上,并且随着β-GP浓度的升高,蛋白缓释总量增大。负载蛋白后,复合膜的理化性能均未发生显著变化（P>0.05）。MTT检测A、B、C 3组的吸光度（OD）值,组间差异具有显著性,A、B组OD值均高于C组,A组OD值高于B组（P<0.05）。A、B组ALP表达高于空白对照组（P<0.05）,A、B 2组之间ALP活性表达亦具有显著差异,A组高于B组（P<0.05）。结论负载EMPs的新型壳聚糖基温敏凝胶膜在体外实验中表现出一定的引导骨再生活性,是一种具有应用潜力的新型生物膜材料。     

壳聚糖/β-甘油磷酸钠引导骨再生膜的制备及表征

目的：制备壳聚糖温敏凝胶引导骨再生屏障膜并进行结构表征。方法：通过分子自组装技术,合成含不同比例β-甘油磷酸钠的壳聚糖温敏凝胶,在37℃条件下干燥成膜。通过傅里叶红外光谱分析、X-射线衍射分析、扫描电镜分析对膜的结构进行表征并测量膜的拉伸强度。结果：壳聚糖温敏凝胶溶液在37℃条件下快速凝胶、脱水后成膜。红外光谱与X-射线衍射分析,壳聚糖与β-甘油磷酸钠之间产生了化学键结合;扫描电镜观察,膜具有多孔的表面结构和内部结构;β-甘油磷酸钠的含量越高,膜的孔径越大,拉伸强度有所降低,拉伸强度为0.78～1.13MPa。结论：壳聚糖温敏凝胶膜的制备条件温和、方法简便,其结构特征和力学性能符合可吸收引导骨组织再生膜的要求。     

缓释骨形态发生蛋白-2的壳聚糖温敏凝胶促进牙周组织再生的实验研究

目的观察自制的加载重组人骨形态发生蛋白- 2（rhBMP- 2）的壳聚糖温敏凝胶修复牙周组织缺损的效果。方法选取3只健康雄性杂种犬制备前磨牙区人工Ⅱ度根分叉区组织缺损模型,随机分为空白对照组、空白凝胶组及载药凝胶组,术中先严密缝合组织瓣,然后对空白凝胶组及载药凝胶组区域分别注射先期配制并消毒好的空白凝胶和载药凝胶,术后8周取材行大体及组织学观察。结果载药凝胶组出现明显的牙周组织再生,而空白对照组和空白凝胶组仅有少量的牙周组织再生。载药凝胶组与空白对照组及空白凝胶组均有统计学差异（P<0.05）,空白对照组和空白凝胶组相比,没有统计学差异。结论载rhBMP- 2的壳聚糖温敏凝胶可有效促进牙周组织再生,同时简化手术操作,是一项有潜力的牙周组织再生手段。     

壳聚糖温敏凝胶膜的制备及其生物活性初步研究

目的：制备壳聚糖/β-甘油磷酸钠（CS/β-GP）温敏凝胶新型可吸收性引导组织再生膜,通过体外细胞培养初步评价其生物相容性。方法：利用（CS/β-GP）体系的温敏相转变特性,合成温敏凝胶膜,并通过FTIR、SEM对膜的结构进行表征。MTT比色法对体外共培养的小鼠成纤维细胞（L929cell）的生长及增殖情况进行初步评价。结果：壳聚糖与β-甘油磷酸钠分子间存在静电作用和化学键结合,最终形成了新的复合生物膜,且具有多孔的表面结构和内部结构。MTT比色法显示与L929细胞体外共培养第3、4、5d,以生物膜为实验组的吸光度（A）值明显高于空白对照组,组间有统计学差异（P〈0.01）。结论：壳聚糖/β-甘油磷酸钠温敏凝胶膜具有多孔结构和良好的生物活性,能促进成纤维细胞的体外增殖,作为一种新型引导组织再膜具有良好的应用前景。     

聚四氟乙烯膜和几丁质膜引导骨再生的基础实验研究

目的：探讨国产聚四氟乙烯膜和自制几丁质膜引导骨再生的效果以及骨缺损大小与修复程度的关系，为临床应用提供依据。方法：在犬胫骨上段内侧制作直径5mm和7mm的洞穿形骨缺损，分别覆盖几丁质膜、聚四氟乙烯膜、及钛网加强的聚四氟乙烯膜，不覆盖膜做空白对照。术后2、4、8、12周取材，通过组织学及新骨形成量观察骨再生情况，比较不同的膜材料引导骨再生效果。结果：术后第2周开始，直径5mm和7mm骨缺损区覆盖膜的三组均有骨再生，至12周时骨缺损区已完全为新骨充填，对照组骨缺损区均为纤维结缔组织充填，相差显著。直径5mm和7mm的骨缺损区在膜覆盖后骨再生量无显著差别。结论：几丁质膜、聚四氟乙烯膜及钛网加强的聚四氟乙烯膜均能引导骨再生。     

引导骨再生技术中屏障膜的应用研究进展

引导骨再生（Guided Bone Regeneration,GBR）技术是目前解决种植体周围骨缺损的有效方法,其原理是使用屏障膜隔离软组织长入骨缺损区,使骨组织的再生功能达到最大程度的发挥。屏障膜在引导骨再生中起着重要的作用,决定了GBR技术的成败,目前临床上应用的屏障膜的种类繁多,性能各异,本文将对目前屏障膜研究及应用展开综述。     

重组人骨形成蛋白-2结合胶原膜在兔颅骨引导骨再生模型中的成骨效应研究

目的    探讨重组人骨形成蛋白-2（rhBMP-2）与胶原膜靶向结合后在兔颅骨引导骨再生（GBR）模型中的成骨效应。方法    将20只普通级雌性健康新西兰大白兔随机分成2周组和6周组,每组10只。所有大白兔均制备颅骨GBR模型,在颅顶骨植入4个钛筒,分别盖rhBMP-2/CBD胶原膜（rhBMP-2/CBD胶原膜组）、rhBMP-2胶原膜（rhBMP-2胶原膜组）、胶原膜（胶原膜组）和不盖膜（空白组）。分别在2周和6周时处死各对应组的大白兔,取样制作硬组织切片和石蜡切片,染色后进行组织学观察。结果    2周时可见胶原膜阻挡了纤维组织的长入,4组钛筒上层均无新骨生成,其中rhBMP-2/CBD胶原膜组钛筒顶端毛细血管增生量明显较其余3组多。6周时可见rhBMP-2/CBD胶原膜组钛筒上层大量新骨生成,与来源于颅骨骨面的新骨界限明显,而其余3组钛筒顶端未见新骨生成。结论    rhBMP-2与胶原膜靶向结合可形成具有骨诱导性的胶原膜,缓释rhBMP-2使胶原膜下方大量新骨生成,表层成骨可阻止纤维组织的长入和防止植骨床的塌陷,使成骨速度加倍。     

可吸收膜在引导骨再生中的应用研究

引导骨再生（Guided Bone Regeneration,GBR）是指利用屏障膜引导骨组织再生防止周围纤维结缔组织过早长入骨缺损区,改变骨创愈合环境,从而促进骨组织再生修复。本文对临床常见的可吸收膜做一综述,研究其在引导骨再生中的作用。     

引导骨再生屏障膜改良的研究进展

引导骨再生术是解决骨组织缺损问题的重要技术,引导骨再生屏障膜在其中发挥着不可替代的作用。引导骨再生膜是防止成纤维细胞进入骨缺损部位的屏障,同时可促进成骨细胞的黏附、增殖和骨组织再生。由于目前广泛应用于引导骨再生的胶原膜尚存在一些缺陷,探索具有更优良性质的引导骨再生屏障膜成为一个重要的课题。因此出现了从抗菌性的改良、成骨性的改良和新材料的研发等多方面的努力以改良引导骨再生膜。本文回顾了近年来引导骨再生膜改进的研究成果和进展,展望了未来相关研究的发展方向,为进一步展开骨再生及修复的相关研究工作提供参考。     

功能等级引导骨再生膜的研究进展

引导骨再生（GBR）是一种利用屏障膜实现骨组织再生的治疗方法。GBR膜的应用作为GBR术的关键,可以封闭骨缺损区,阻止非成骨细胞长入,为骨组织的再生创造一个良好的环境。然而,目前市面上的GBR膜往往缺乏骨诱导潜力和抗菌活性。为了实现屏障膜的多种功能需求,许多学者致力于研究具有梯度空间结构和功能的复合膜。本文将回顾功能等级GBR膜的研究进展并对其未来发展方向进行展望,为GBR膜的进一步研究提供思路。     

引导骨再生屏障膜改良的研究进展

引导骨再生术是解决骨组织缺损问题的重要技术,引导骨再生屏障膜在其中发挥着不可替代的作用。引导骨再生膜是防止成纤维细胞进入骨缺损部位的屏障,同时可促进成骨细胞的黏附、增殖和骨组织再生。由于目前广泛应用于引导骨再生的胶原膜尚存在一些缺陷,探索具有更优良性质的引导骨再生屏障膜成为一个重要的课题。因此出现了从抗菌性的改良、成骨性的改良和新材料的研发等多方面的努力以改良引导骨再生膜。本文回顾了近年来引导骨再生膜改进的研究成果和进展,展望了未来相关研究的发展方向,为进一步展开骨再生及修复的相关研究工作提供参考。     

Biological effects of drug-loaded biodegradable membranes for guided bone regeneration

The biological effects of drug-loaded biodegradable novel membrane for guided bone regeneration (GBR) was evaluated. The membranes were polyglycolic acid mesh coated with poly-L-lactic acid containing flurbiprofen, tetracycline or PDGF-BB. Porous structure was generated in the membranes by using a phase inversion method. The membrane was less toxic, nicely biodegradable and biocompatible for 8 wk after implantation in the dorsal skin of the rat. The drugs released from the membranes were shown to be effective for new bone formation. Tetracycline, flurbiprofen or PDGF-BB loaded membrane was markedly effective for osteoid tissue and new bone formation in the bony defect prepared in rat calvaria to compare with that by unloaded membrane. These results suggested that drug-loaded biodegradable barrier membrane might be a potential tool for GBR in periodontal therapy.     

Migration of osteoblastic cells on various guided bone regeneration membranes

To evaluate the biological effects of guided bone regeneration (GBR) barrier materials on osteoblastic cell migration, migration of mouse osteoprogenitor cells (MC3T3-E1) was examined, in vitro, on various membranes. Eight commercially available GBR membranes - bovine type I collagen (BioMend; BM), porcine type I collagen (BioGide; BG), bovine type I atelocollagen (Tissue Guide; TG), polylactic acid (Epi-Guide; EG), co-polymer of polylactic acid and polyglycolic acid (Resolute; RL, Resolut XT; RL-XT), expanded polytetrafluoroethylene (e-PTFE; Gore Tex; GT) and co-polymer of cellulose acetate and nitrocellulose (Millipore filter; MP) - were tested. A 3x5 mm section of the membrane was fixed to the bottom of a culture dish with double-sided adhesive tape, and half of the membrane was closely covered by PARAFILM (American National Can) to leave an unexposed area for cell migration. The border between exposed and unexposed areas was marked as a baseline of cell migration. Membranes were then plated with 3 ml of cell suspension at an initial density of 1x105 cells/ml in alpha-MEM culture medium with 10% fetal bovine serum and ascorbic acid. After a 5-hour incubation, non-attached cells were completely washed out with phosphate buffered saline and the PARAFILM cover was removed. After 3 days cultivation, specimens were fixed with 10% buffered formalin and stained briefly with hematoxylin. The area of cell migration on a membrane was analyzed using a LA 500 Image Analysis System and migration area per unit length of the baseline (mm2/mm) was compared among membranes. Results demonstrated that cell migration was greater in the order: RL>RL-XT, BM, TG, MP>EG, BG. Membranes except for BG, EG and GT showed the migration rate equal to or higher than a plastic culture cover slip (Celldesk) (P<0.01) on which cells generally grow favorably. Only a small number of the cells attached to GT, and the net cell migration for the membrane could not be determined. These results indicate that GBR barrier materials per se may influence the process of bone regeneration in vivo through the effects of their presence on cell migration.     

Effects of cortical bone perforation on experimental guided bone regeneration

This study was designed to evaluate the effects of cortical bone perforation histologically and histomorphometrically on guided bone regeneration (GBR) in rabbits. After elimination of the periosteum, cortical bone defects of two sizes were made in the external cortical plate of the frontal bone (Group A: 1 x 15 mm; Group B: 3 x 15 mm). A non-resorbable membrane filled with autogenous blood was placed in the experimental area and secured with titanium pins. After 1 and 2 weeks, vascularized connective tissue and new bone were generated in the space surrounding the defects in both the groups. The amount of vascularized connective tissue generated in Group B was greater than that in Group A at 1 week. Alkaline phosphatase (ALP) was expressed on the bone surrounding the perforation. The expression of ALP was more extensive in Group B than in Group A and was proportional to the breadth of perforation. At 2 weeks, the perforated region was almost covered with new bone in Group A. ALP was expressed at the periphery of newly formed bone. The expression of ALP was proportional to the breadth and height of perforation. At 6 weeks, semicircular outgrowth of bone towards the periphery of the perforated region was observed in both the groups. Newly formed bone volume and ALP expression in Group B were more extensive than those in Group A. At 12 weeks, the space was filled with bone and connective tissue in both the groups. There was no difference in ALP expression between Groups A and B. Histomorphometric analysis showed significant differences between both the groups (two-way ANOVA, P<0.01). We conclude that a larger perforation is associated with prompter bone formation in the secluded space during GBR.     

Clinical outcome of autogenous bone blocks or guided bone regeneration with e‐PTFE membranes for the reconstruction of narrow edentulous ridges

The aim of this study was to analyse the clinical outcome of two different surgical methods for the reconstruction of narrow edentulous ridges before implant installation: guided bone regeneration with e-PTFE membranes and autologous bone chips or grafting of autologous bone blocks without e-PTFE membranes. Thirty partially edentulous patients, presenting insufficient bone width (less than 4 mm) in the edentulous sites for installation of screw-type titanium implants, were selected and assigned to two different treatment modalities. Fifteen patients (group 1) were treated by means of guided bone regeneration with e-PTFE membranes supported by stainless steel screws and autologous bone chips taken from intraoral sites. Fifteen patients (group 2) were treated by means of autologous bone blocks taken from intraoral or extraoral sites (anterior iliac crest and calvaria) and stabilized with titanium microscrews. Six to 8 months later, during re-entry for implant insertion, the gain of ridge width obtained was measured. In group 1 the average amount of bone gain was 2.7 mm, whereas in group 2 the value was 4.0 mm. Five to 6 months after implant placement prosthetic rehabilitation was started. The mean follow-up after prosthetic load has been 22.4 months. Success rates of implants according to Albrektsson criteria has been 93.3% in group 1, and 90.9% in group 2. Although a statistical comparison between the two treatment modalities may not be feasible, due to the bias resulting from the choice of treatment by the clinician and from the differences in donor sites and defect extension, some considerations can be made: 1) both methods are a reliable means for the correction of narrow edentulous ridges; 2) both techniques necessitate overcorrection of the defect because of interposition of connective tissue beneath the membrane in the first group and bone resorption in the second one; 3) the use of semipermeable barriers increases the costs of the surgical procedure, as compared to bone grafting without membranes; 4) guided bone regeneration presents a higher risk of infection because of wound dehiscence and membrane exposure. Therefore, in case of wide edentulous areas, reconstruction of narrow ridges should be performed with bone blocks without membranes.     

Long-term stability of autogenous bone grafts following combined application with guided bone regeneration

The aim of the study was to compare the long-term stability of membranous and endochondral autogenous bone grafts with or without combined application of guided bone regeneration (GBR). Twenty-five, male, 6-month old, albino rats were used in the study. The animals were divided into four groups (A5, A11, B5 and B11). Group A5 (control): The inferior border of the mandible was exposed in both sides. At one side of the jaw, a calvarial bone graft (baseline -3 x 4 x 0.64 mm) was placed at the inferior border of the mandible and was fixed with a standardized screw-type titanium microimplant. At the contralateral side, an ischiac bone graft (baseline -3 x 4 x 0.87) was transplanted. The healing period was 5 months. Group A11 (control): The animals were treated in the same manner as in Group A5 with the difference that the healing period was 11 months. Group B5 (test): The animals were treated in the same manner as in Group A5 with the difference that an e-PTFE membrane was adapted over the bone graft on each side of the jaw. Group B11 (test): The animals were treated in the same manner as in Group B5 with the difference that 5 months following transplantation the animals were subjected to a second operation and the membranes were removed. The healing period was 11 months. The animals were killed at 5 (Groups A5 and B5) or at 11 months (Groups A11 and B11) following mandibular augmentation and the jaws were defleshed. The width, the length and the thickness/height of the bone graft were evaluated by means of a stereomicroscope. At 5 months, both types of the membrane-treated bone grafts presented increase in all dimensions compared with baseline. However at 11 months, both types of the membrane-treated bone grafts exhibited a decrease in their dimensions which were similar to the baseline measurements. In the control groups, both types of bone graft presented significant resorption both at 5 and at 11 months with the ischiac bone grafts presenting more resorption in width and length than the calvarial bone grafts. It can be concluded that the long-term volume stability of autogenous endochondral and membranous onlay bone grafts combined with GBR is superior to that of autogenous endochondral and membranous onlay bone grafts alone.