聚乳酸-羟基乙酸在骨组织工程支架材料中的应用

因外伤、肿瘤等多种原因造成的骨组织缺损需要良好的骨组织替代物修复。随着骨组织工程的不断发展,为骨缺损的修复带来了新思路。学者们一直致力于研发与改性各种骨组织工程支架材料以更好地帮助修复骨缺损。聚乳酸-羟基乙酸因具有良好的生物降解性、生物相容性等优点而备受关注。本文仅对近年来在骨组织工程中聚乳酸-羟基乙酸支架材料的改性与设计进行简要综述。     

骨组织工程技术及其在颌骨修复重建中的应用

由于先天畸形、外伤、肿瘤、炎症、牙周病所致的颌骨缺损和缺失是口腔颌面外科功能性重建的重要课题.传统的方法如骨移植、骨代用品和人工材料的应用以及牵引成骨都存在一定的局限性,包括供区的创伤、排异反应和疾病的传播等.90年代以来,组织工程学和骨组织工程学的发展为颌骨缺损和缺失的修复重建开创了一条新的途径.本文就这门学科的发展概况、应用于颌骨修复中的三个关键问题(组织工程的种子细胞、支架材料和血管化问题)以及在颌骨修复重建中的实验研究和临床前景作一概述.     

可降解新型聚乳酸膜在引导骨组织再生中的应用

目的 探索一种可降解新型聚乳酸膜（PDLLA/PLLA）在引导骨组织再生中的应用效果。方法 新西兰大白兔24只,体重2.5～3.0 kg,在动物一侧下颌骨体部近下颌骨下缘处制备10 mm×5 mm×3 mm箱状骨缺损,然后将动物随机分为实验组、对照组和空白组,每组8只。实验组动物骨缺损处填Bio-oss骨粉后将PDLLA/PLLA覆盖于缺损表面,对照组动物骨缺损处填Bio-oss骨粉后将Guidor聚乳酸可吸收膜覆盖于缺损表面,空白组动物不作处理。术后8、12周采集缺损处标本,进行大体观察、Micro-CT检查和组织病理学观察。结果 实验期间各组实验动物均未发生炎症和排异反应,各组创口愈合良好,成骨活跃。大体观察显示,术后8周实验组动物成骨量较多,材料降解较少,对照组动物成骨量较实验组少,材料降解完全;术后12周实验组动物和对照组动物成骨量相当,实验组材料进一步降解,空白组动物成骨量少于实验组和对照组。术后8、12周,Micro-CT可以观察到实验组和对照组缺损区域新生骨明显多于空白组。术后8、12周,实验组动物和对照组动物新生骨相对骨体积分数（BV/TV）、骨密度（BMD）和骨小梁数...     

聚乳酸-纳米羟基磷灰石-丝素蛋白引导骨再生膜的制备及表面特征

目的制备一种新型的聚乳酸-纳米羟基磷灰石-丝素蛋白(polylactic acid/nano-hydroxyapatite/silk fi-broin,PLLA/n-HA/SF)纳米纤维引导骨组织再生膜,初步探讨其作为引导骨再生屏障膜的可行性。方法采用热致相分离法制备PLLA/n-HA/SF纳米纤维复合膜,通过扫描电镜对其形貌进行研究,利用傅里叶红外光谱仪分析纳米羟基磷灰石和丝素蛋白的加入对所制备的复合膜结构的影响,并计算其孔隙率。结果扫描电镜显示该复合膜具有纳米纤维状三维网络结构。纤维直径约为160～320nm,孔径大小为1～4μm,丝素蛋白和纳米羟基磷灰石在复合膜中分散均匀。红外光谱结果表明PLLA/n-HA/SF复合膜具备聚乳酸、纳米羟基磷灰石及丝素蛋白的特征峰表现,3种组分之间结合良好。该膜的孔隙率为92.600%。结论热效相分离法制备的PLLA/n-HA/SF复合膜具有良好的微观结构和较高的孔隙率。     

聚乳酸⁃羟基乙酸共聚物在牙髓疾病治疗中的应用前景

材料学的发展对牙髓疾病的治疗有重要意义,聚乳酸?羟基乙酸共聚物[poly(lactic?co?glycolic acid),PLGA]是一种被广泛应用于生物医用材料制备的有机高分子化合物。近年来,作为载药/分子系统和组织再生支架在牙髓疾病治疗中展现出应用前景,本文将对PLGA在牙髓疾病治疗中的应用作一综述,为其进一步开发利用提供参考。文献复习结果表明,PLGA作为药物/分子输送系统主要应用于盖髓材料、根管消毒剂和根尖诱导成形剂的改良。PLGA改良盖髓材料能延长药物作用时间、降低毒性;改良根管消毒剂能实现药物缓释,使药物深入更细微的结构,与致病菌有更广泛的接触;改良根尖诱导成形剂能为根尖诱导提供更便捷的给药方式。PLGA作为组织工程支架主要应用于牙髓再生的研究,通过PLGA物理性能、作用环境的不断优化为种子细胞提供更适宜增殖分化的微环境。如何合理利用PLGA的优势,研制出更适宜根管内应用的材料,还需要进一步的研究。     

羟基磷灰石+医用胶原膜在颌骨囊肿骨腔中的应用

羟基磷灰石(hydroxyapatite,HA)是一种新型骨代用品,具有良好的生物相容性,能引导骨组织再生,已被广泛应用于临床,对口腔颌面部硬组织缺损的修复,如颌骨囊肿术后骨腔填塞取得了很好的疗效。我科自1995年以来,对27例颌骨囊肿骨腔充填HA,经5年临床随访观察,效果满意,现报告如下。     

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。     

膜引导骨组织再生术在上颌前牙区种植中的应用

目的:探讨膜引导骨组织再生(membrane guided bone regeneration,MGBR)技术中,生物胶原膜在上颌前牙区种植骨增量中的作用.方法:选取我院2008年1月至2009年12月间上前牙区唇腭向骨量不足种植病例55例,随机分为2组,29例使用MGBR,同期植入种植体40颗(有膜组);另26例不应用MGBR,植入种植体40颗(无膜组),作为对照.观察2组患者种植前及修复前种植区牙槽骨的情况.用卡尺测量牙槽骨唇腭向厚度,用X线骨密度分析法评估平均密度的变化.采用X线片图像分析测量软件(Sidexis)和SPSS16.0软件包进行比较分析.结果:单因素分析显示,有膜组种植术前与永久修复前牙槽骨唇腭向的厚度及密度差别有统计学意义(P<0.05);种植术前与永久修复前,有膜组与无膜组牙槽骨唇腭向厚度及骨密度变化的差别有统计学意义(P<0.05).结论:使用生物膜的患者,唇腭向骨厚度及密度的增加均优于未使用生物膜的患者.在上前牙区骨量不足患者的种植术中,可推荐使用MGBR技术.     

聚羟基丁酸-羟基戊酸共聚酯膜引导骨组织再生的初步研究

目的 探讨聚羟基丁酸-羟基戊酸共聚酯(PHBV)膜的生物相容性及其成骨能力.方法 采用骨髓基质细胞体外培养技术,通过MTT法检测细胞相对增殖度,对PHBV的细胞毒性进行分级评价;并制备犬胫骨骨缺损模型,观察PHBV膜引导骨再生的效果.结果 PHBV膜的细胞毒性分级为0 ～ 1级;PHBV膜覆盖组术后第2周即可见新骨形成,12周时骨缺损区已完全为新骨充填,骨修复质量明显优于对照组.结论 PHBV膜对骨髓基质细胞无明显毒性,能引导骨组织再生,有望成为一种较理想的引导骨组织再生的天然膜材料.     

可吸收性Bio-Gide膜治疗下颌角区局部骨缺损实验研究

目的 :本研究旨在探讨Bio-Gide膜治疗局部骨缺损的效果 ,评估其应用价值。方法 :在8只成年健康雄性新西兰大白兔的双侧下颌角区置备5×5mm2 大小的洞穿性骨缺损 ,一侧为实验侧 ,另一侧为对照侧 ,随机分成2组 (4周 ,8周组 ) ,进行肉眼、x线与组织学观察。结果 :肉眼及x线检查结果显示 :两组动物的对照侧骨缺损均明显存在 ,有的骨缺损内有肌肉长入 ,骨缺损面积增大 ;两组动物的实验侧骨缺损有不同程度修复 ,并测得实验侧骨缺损中央2×2mm2区域的平均骨密度高于对照侧 ,两者在统计学上有显著差异。组织学检查实验侧骨缺损骨性修复。结论 :Bio-Gide膜能有效阻挡软组织长入骨缺损区 ,作为骨细胞载体促进骨修复。     

引导组织和骨组织再生术及其生长因子在牙周骨缺损治疗中的应用

引导组织再生术和引导骨再生术广泛用于牙周骨缺损的治疗中,给牙周组织再生开辟了广泛的空间,但二者单独使用却存在一定的局限性。因此,目前的研究多趋向于将骨移植材料和膜材料与多肽生长因子联合应用于牙周骨缺损的修复。下面就引导组织再生膜材料、引导骨再生支架材料和碱性成纤维细胞生长因子的理化性质、生物学功能,以及三者联合应用于牙周骨缺损治疗中的作用作一综述。     

GBR技术应用于上前牙种植骨缺损的临床研究

目的：评估引导骨再生技术（GBR）在上前牙不同类型骨缺损种植修复中的效果。方法：对35例上前牙牙槽骨缺损种植的患者采用GBR技术进行骨增量,其中29例种植体周围骨缺损患者仅采用GBR技术,在植体植入骨床后,同期植入Bio～oss人工骨粉,表面盖Bio～gide可吸收性胶原膜;6例牙槽骨缺损患者采用移植自体块状骨联合Bio～oss人工骨粉,盖Bio～gide可吸收性胶原膜,5～6个月后行Ⅱ期种植体植入术。结果：所有患者在植体植入术后6～12个月临床观察种植体与骨结合良好,软组织形态与周围组织一致,行冠或桥修复,修复后12个月随诊复查无种植体失败。结论：引导骨再生技术皆能有效地对上前牙不同类型骨缺损进行骨增量,符合美学种植要求。     

作为GBR屏障膜的新型胶原膜的体内植入效果分析

［摘要］ 目的 探讨Ⅰ型胶原和矿化Ⅰ型胶原合成的胶原膜作为GBR屏障膜在动物体内植入后,诱导早期膜下成骨的能力。方法 实验于2013年10月—2014年3月在沈阳军区总医院动物实验中心完成。选取小型巴马猪双侧下颌骨,分别于下颌骨骨体处用牙科裂钻制备8 mm×8 mm全层骨缺损3个,分别应用实验胶原膜覆盖、Bio-gide@覆盖、无覆盖膜骨缺损区。术后1个月处死动物,在处死前1、2周分别肌肉注射四环素溶液与二甲酚橙溶液。固定样本后,制备硬组织切片。分别在荧光显微镜及光学显微镜下（甲苯胺蓝、亚甲基蓝-酸性品红染色）观测膜的降解程度及膜下新骨生成能力,评价材料膜下骨形成量和骨成熟程度。结果 实验组胶原膜具备良好的屏障作用,膜下新生骨矿化程度良好;骨小梁排列整齐,但新生骨量少于Bio-gide@覆盖组;无覆盖膜骨缺损区新生骨组织骨小梁排列混乱,新生骨量少。 结论 新型胶原膜在1个月时体内无明显降解,具备良好的膜下成骨能力,下一步需进行实验组胶原膜的改性,以增加胶原膜膜下成骨量。     

Guided bone regeneration in mandibular defects in rats using a bioresorbable polymer

The aim of this study was to explore the possibility of obtaining bone regeneration in jaw bone defects in rats after coverage of the defects with an occlusive bioresorbable membrane. The experiment was carried out in 31 rats. The mandibular ramus was exposed in both sides and a 2 x 3 mm defect was produced at its lower border. A gutta‐percha point was placed to indicate the original level of the border. The defect on one side was covered with a polyhydroxybutyrate resorbable membrane, whereas the contralateral side received no membrane before closure of the wound. Macerated jaw specimens representing 3 and 6 months of healing demonstrated minimal bone fill in the control defects, whereas all test defects healed to or close to the gutta‐percha point, indicating the original inferior border of the jaw. The histological analysis demonstrated increasing bone fill in the test specimens from 15–180 days, whereas only 35–40% of the defect area in the control sides was filled with bone after 3–6 months. Ingrowth of muscular. glandular and connective tissue was consistently occurring in the control defects during healing. It can be concluded that selective repopulation of bone defects with bone‐forming cells can be ensured by excluding surrounding soft tissues from the wound area with an occlusive bioresorbable membrane.     

Evaluation of guided tissue regeneration in interproximal defects

Abstract This study clinically evaluates the use of expanded polytetrafluoroethylene (ePTFE) membranes with or without the addition of decalcified freeze-dried hone allograft (DFDBA) in the treatment of interproximal intraosseous defects, 25 patients (26 paired defects) diagnosed with advanced periodontitis and having at least 2 bilateral interproximal probing depths of s6 mm participated in the study. After the hygiene phase, measurements were made to determine soft tissue recession, pocket depth, and clinical attachment levels. Defects from each pair were randomly treated with either ePTFE alone (control), or ePTFE + DFDBA (experimental). Measurements were made during the surgery to determine crestal resorption, defect resolution and defect fill. Membranes were removed at 4 to 6 weeks. At 6 months, the soft and hard tissue measurements (surgical reentry) were repeated. Both groups showed statistically significant improvement when compared to baseline (p<0.001), but no difference was determined between groups. Control sites showed a 50% bone fill and experimental sites had 54% bone fill. The defect resolution changes were also similar between control and experimental groups, respectively (80%, 74%). For this short-term study, it was concluded that either technique was beneficial for the treatment of intraosseous defects. Other studies are needed to assess the long-term stability of the improvements rendered by these treatments.     

Collagen gel and membrane in guided tissue regeneration in periodontal fenestration defects in dogs

Abstract The effect of a collagen gel matrix as a submembranous space-maintaining material was evaluated in guided tissue regeneration procedures. In 4 dogs, contralateral surgical circular fenestration defects, 5 mm in diameter, were produced at the midbuccal aspect of the alveolar bone in 8 maxillary canines. Removal of bone, PDL and cementum was complete. Experimental sites were filled with collagen gel and covered with collagen membranes; control sites were covered with collagen membranes and the underlying space was spontaneously filled with blood. Mucogingival flaps were repositioned. Histological and histomorphometric observations, 6 weeks post-surgery, indicated that defects covered by collagen membranes presented the most impressive regeneration with almost complete coverage of the denuded root by new cementum (98.4%) and new bone (63.2%). In the experimental defects. 83.5% coverage of new cementum with only 21.9% new bone regeneration was observed. These results suggest that collagen gel. interfered with healing by PDL and bone-derived cells in the submembranous space.     

引导骨组织再生膜应用于自身骨移植的研究现状

自身骨移植是种植术前骨增量的一种重要的技术手段。对于在常规骨移植后是否在移植物上覆盖引导骨组织再生膜,临床上存在着较大争议。笔者拟就引导骨组织再生膜在自身骨移植中的应用研究作一综述。     

Bone reconstruction following implantation of rhBMP-2 and guided bone regeneration in canine alveolar ridge defects

BACKGROUND: Alveolar ridge aberrations commonly require bone augmentation procedures for optimal placement of endosseous dental implants. The objective of this study was to evaluate local bone formation following implantation of recombinant human bone morphogenetic protein-2 (rhBMP-2) in an absorbable collagen sponge (ACS) carrier with or without provisions for guided bone regeneration (GBR) as potential treatment modalities for alveolar augmentation. METHODS: Surgically induced, large, mandibular alveolar ridge saddle-type defects (2 defects/jaw quadrant) in seven young adult Hound dogs were assigned to receive rhBMP-2/ACS, rhBMP-2/ACS combined with GBR (rhBMP-2/GBR), GBR, and surgery controls. The animals were euthanized at 12 weeks post-surgery when block sections of the defect sites were collected for histologic analysis. RESULTS: Clinical complications included swelling for sites receiving rhBMP-2 and wound failure with exposure of the barrier device for sites receiving GBR (4/6) or rhBMP-2/GBR (3/7). The radiographic evaluation showed substantial bone fill for sites receiving rhBMP-2/ACS, rhBMP-2/GBR, and GBR. In particular, sites receiving rhBMP-2/GBR presented with seroma-like radiolucencies. The surgery control exhibited moderate bone fill. To evaluate the biologic potential of the specific protocols, sites exhibiting wound failure were excluded from the histometric analysis. Sites receiving rhBMP-2/ACS or rhBMP-2/GBR exhibited bone fill averaging 101%. Bone fill averaged 92% and 60%, respectively, for sites receiving GBR and surgery controls. Bone density ranged from 50% to 57% for sites receiving rhBMP-2/ACS, GBR, or surgery controls. Bone density for sites receiving rhBMP-2/GBR averaged 34% largely due to seroma formation encompassing 13% to 97% of the sites. CONCLUSION: rhBMP-2/ACS appears to be an effective alternative to GBR in the reconstruction of advanced alveolar ridge defects. Combining rhBMP-2/ACS with GBR appears to be of limited value due to the potential for wound failure or persistent seromas.     

Healing patterns in calvarial bone defects following guided bone regeneration in rats. A micro-CT scan analysis

OBJECTIVE: The objective of this study was to evaluate healing patterns of critical-size calvarial bone defects treated according to principles of guided bone regeneration using micro-CT scan analysis. Specifically, the contribution of bone, periosteum and dura mater to the amount and mineralization of newly formed bone was evaluated. MATERIAL AND METHODS: Surgically induced, critical-size calvarial bone defects in 48 adult male Wistar rats received the following: an occlusive expanded polytetrafluoroethylene (ePTFE) membrane at the exo- and endocranial aspect (OO; n = 12); an occlusive membrane at the exocranial and a perforated membrane at the endocranial aspect (OP; n = 12); a perforated membrane at the exocranial and an occlusive membrane at the endocranial aspect (PO; n = 12); and a perforated membrane at the exo- and endocranial aspect (PP; n = 12). The animals were euthanized at 4 weeks for quantitative analysis of bone volume fraction and mineralization in the region of interest (ROI) as well as in the external, middle and central area of the defect using micro-CT. RESULTS: Bone volume fraction ranged from 31.4% (OP) to 24.5% (PP). No differences were found among the groups. Bone volume fraction and mineralization in the middle area were significantly greater in group OP than in group PP, and in the central area in group OO and PO than in group PP. CONCLUSIONS: The results of this study suggest that use of occlusive ePTFE membranes enhances bone formation and maturation in the calvarial skeleton. When occlusion of endo- and exocranial tissues was compromised by membrane perforation, impaired bone formation and mineralization were observed.