骨形成蛋白与胶原基纳米骨修复牙周骨缺损的实验研究

目的 探讨重组人骨形成蛋白-2(rhBMP-2)和胶原基纳米骨复合材料(nHAC)修复牙周骨缺损的效果.方法 制备小型猪牙周骨缺损模型,设立rhBMP-2-nHAC复合材料植入组、空白对照组和单纯植入胶原基纳米骨组,术后8周观察各组间修复效果及组织病理学变化,通过骨组织形态计量学测定分析评价牙周骨组织的再生情况.结果 术后8周可见复合材料植入组大量新生牙周组织生长,四环素单标记表面、四环素双标记表面、骨矿化沉积率、骨体积、类骨质表面、成骨细胞表面等骨组织形态计量学结果 与空白对照组和单纯胶原基纳米骨组比较,差别均有统计学意义(P ＜ 0.05).结论 rhBMP-2和nHAC可明显促进牙周骨缺损修复.     

纳米晶羟基磷灰石复合胶原材料在拔牙创修复中的作用

目的:探讨纳米晶羟基磷灰石复合胶原材料(nHAC)在拔牙创修复中的作用。方法:拔除12只成年狗两侧下颌第二及第三切牙,并去除牙槽间隔,一侧随即植入nHAC,对侧植入致密多晶羟基磷灰石微粒人工骨(HA)作为对照。于植入后4、8、12周分别取材,采用99mTc MDP核素骨显像、组织学观察、图像分析等方法比较两种植入材料在牙槽窝中的骨修复能力。结果:nHAC植入牙槽骨后,材料被逐渐降解吸收,新骨不断生成,12周后植入材料几乎完全被成熟的骨组织取代;图像分析结果显示不同时间nHAC组新骨形成的比值显著高于HA组(P<0.01);4、8、12周nHAC组浓聚程度均高于HA组。结论:nHAC在修复拔牙创缺损时比HA效果更好,是一种较为理想的骨替代材料。     

种植体周围骨缺损修复的组织学观察

目的 :观察脱钙冻干骨移植物 (DFDBA)在种植体周骨缺损的诱导成骨活性以及重组人骨形成蛋白 -2 (rhBMP -2 )和钛膜对DFDBA成骨作用的影响。方法 :犬股骨植入种植体周围 ,制造 4mm× 3mm× 3mm骨缺损 ,分别采用DFDBA、DFDBA rhBMP -2和DFDBA 钛膜三种不同方法修复种植体周骨缺损 ,术后 4、8、12周 ,组织学观察种植体周骨缺损修复情况。结果 :三组实验动物中 ,植骨创均愈合良好 ,种植体无松动 ,未见种植体周围炎发生。①DFDBA组 :术后 4周即有新生骨小梁形成 ,术后 12周修复骨缺损 ,但新骨组织与宿主骨之间仍见明显分界 ;②DFDBA rhBMP -2组 :成骨过程较早 ,术后 4周即有较多新生骨组织出现 ,术后 8周 ,成骨细胞较为丰富 ,术后 12周新骨组织与宿主骨完全融合 ;③DFDBA 钛膜 :术后 4周即见新生骨小梁沿钛膜生长 ,至术后 12周 ,完全覆盖骨缺损。结论 :DFDBA具有良好的骨诱导和骨引导作用 ,可用于修复种植体周骨缺损 ;rhBMP -2复合DFDBA ,可增强骨诱导作用 ,加速成骨过程 ;钛膜有助于维持骨再生空间 ,阻隔软组织长入 ,引导新骨生长 ,缩短修复过程。     

活性纳米羟基磷灰石复合胶原/聚乳酸材料对拔牙创早期愈合及牙槽嵴吸收影响的实验研究

目的 观察活性纳米羟基磷灰石复合胶原/聚乳酸材料(AnHAC/PLA)促进犬拔牙创早期愈合及减少牙槽嵴吸收的效果。方法 将小块状纳米羟基磷灰石复合胶原/聚乳酸材料(nHAC/PLA)、AnHAC/PLA、自体牙槽松质骨植入犬拔牙创中,并设空白对照。术后4周、8周、12周通过大体观察测量、HE染色和M asson′s三色法染色来观察比较拔牙创骨缺损的修复情况及牙槽嵴的吸收情况。结果 AnHAC/PLA材料修复拔牙创骨缺损及减少牙槽骨吸收的能力强,与自体牙槽松质骨组类似,nHAC/PLA材料的能力较弱,但明显优于空白对照组。结论 AnHAC/PLA可早期修复拔牙创,减少牙槽嵴的吸收。     

可吸收性胶原膜引导即刻植入种植体周围骨组织再生的实验研究

目的探讨可吸收性胶原膜引导即刻植入种植体周围骨组织再生的效果。方法在12只成年杂种狗下颌第3、4前磨牙新鲜拔牙创即刻植入种植体的近中形成3 mm×3 mm×5 mm骨缺损区,按自身同期对照研究设计,右侧为实验侧,骨缺损区上覆盖Co膜;左侧为空白对照侧,骨缺损区不覆盖Co膜。术后1、2、4、6个月分别处死一组动物,摘取下颌骨,采用大体观察、X线摄片、组织学观察、扫描电镜及生物力学（拔出实验）测定等方法检测缺损区骨组织再生的情况。结果实验侧种植体周围骨缺损区较空白对照侧新骨形成量多、外形好、骨成熟时间早,加速了骨组织的再生过程。结论可吸收性胶原膜具有良好的生物相容性和可降解性,可用作骨组织引导再生膜,以期促进骨缺损的再生修复,其促进作用主要表现在骨组织愈合的早期。     

活性纳米羟基磷灰石复合胶原聚乳酸材料异位成骨性能研究

目的：探讨既具有骨引导性又具有骨诱导性的活性纳米羟基磷灰石复合胶原/聚乳酸（AnHAC/PLA）材料的异位成骨能力,为该材料作为植骨材料应用于临床打下实验基础。方法：通过扫描电镜观察rhBMP-2与nHAC/PLA材料的复合情况,并将nHAC/PLA、rhBMP-2、AnHAC/PLA材料分别植入小鼠股后肌袋内,术后2周、6周通过X线片、组织学观察、成骨量测定来研究AnHAC/PLA的异位成骨能力。结果：rhBMP-2在nHAC/PLA孔隙中均匀分布,6周时AnHAC/PLA组诱导形成的骨量是rhBMP-2组的10.5倍。结论：AnHAC/PLA材料具有良好成骨能力,nHAC/PLA是rhBMP-2理想的缓释载体。     

Cem-Ostetic/rhBMP-2复合物促进即刻种植体周围骨组织再生的研究

目的：研究Cem-Ostetic/rhBMP-2对即刻种植骨缺损修复的生物学特性。方法：将6只狗随即分成2组,拔除犬双侧下颌第二、三、四前磨牙,即刻植入种植体,每个种植体颊侧制备标准缺损,分别植入Cem-Ostetic/rhBMP-2、Cem-Ostetic、自体骨。术后6、12周分期处死,进行大体、影像学、组织学观测。结果：术后6、12周各组均有不同程度的骨组织再生。各个时期观察显示Cem-Ostetic/rhBMP-2组新生骨与种植体间的骨结合较其他组多。结论：Cem-Ostetic/rhBMP-2能有效促进种植体周围骨缺损修复,并促进种植体-骨界面形成较完善的骨整合。     

rhBMP-2在种植体周围骨缺损修复中应用的组织学观察

目的:研究rhBMP-2及不同载体在种植体周围骨缺损修复中的应用。方法:在beagle犬下颌骨植入种植体,颊侧形成裂开性骨缺损,置入复合了不同浓度rhBMP-2的珊瑚羟基磷灰石人造骨(CHA)或可吸收胶原海绵(ACS)。种植体植入后2、4、8、12周,获取含种植体骨标本,进行组织学观察。结果:2周时,rhBMP-2组可见极少量的新生骨组织。4周时,rhBMP-2/ACS组新骨组织由牙槽骨顶端向缺损区中心方向生长;rhBMP-2/CHA组人造骨颗粒内部和周围出现呈岛状生长的新生骨组织。8周时,rhBMP-2/ACS组的新骨形成大片状结构;rhBMP-2/CHA组人造骨颗粒周围较多骨岛形成。12周时,rhBMP-2组的缺损区内骨量和骨高度进一步增加,与种植体形成骨性结合。浓度为0.05 mg/ml和0.2 mg/ml,载体为CHA或ACS促进骨再生作用差异无统计学意义。结论:以CHA或ACS为载体rhBMP-2能促进种植体周围骨缺损区内的骨组织再生并与种植体表面较好地结合。     

Bio-oss结合Bio-gide修复牙种植体周围骨缺损的组织学研究

目的：通过制作带有种植体的硬组织磨片,评价无机牛骨(deproteinized natural bovine mineral,Bio-oss)结合可吸收性胶原膜(bioresorbable collagen mambrane,Bio-gide)在牙种植体周围骨缺损中的引导骨再生作用及效果。方法：在免股骨植入羟基磷灰石涂层BLB种植体,并在其外侧壁制造标准骨缺损,A组在骨缺损处植入Bio-oss颗粒并在其表面覆盖Bio-gidt,膜,B组作为空白对照,分别于术后1、2、4、6个月取样品,通过带种植体的硬组织切片进行骨组织形态学分析。结果：术后1个月Bio-oss颗粒表面有新骨形成,随时间延长Bio-oss发生降解吸收,新生骨量增加,并与种植体表面形成骨性结合。结论：可吸收性胶原膜Bio-gide结合Bio-oss应用于牙种植体周围骨缺损中,可以引导骨组织再生,重建缺损的骨组织,新生骨与种植体形成骨性结合。     

胶原基纳米骨结合胶原膜修复兔下颌骨缺损的研究

目的　研究胶原基纳米骨 (nHAC)结合可吸收性胶原膜 (GTR)修复下颌骨缺损的效果 ,以期为临床提供一种理想的骨替代材料和可吸收性引导骨再生膜。方法　在 14只成年兔双侧下颌骨下缘形成 8mm× 6mm全层骨膜骨质缺损 ,每一缺损作为一个实验单位。术后 6、8、12周取材 ,行大体标本 ,X线片 ,组织学和扫描电镜观察。结果　 8周时 ,nHAC/GTR成骨量尚不如Bio -Oss/Bio-Gide ,12周时已接近Bio -Oss/Bio -Gide ,而且两组的骨修复方式很类似 ;nHAC/GTR与CPC/GTR相比同期成骨量大。空白缺损组则未能修复。结论　nHAC/GTR生物相容性好 ,同期成骨量较好于CPC/GTR ,远期成骨量与Bio -Oss/Bio -Gide相似 ,是一种较为理想的骨替代材料和可吸收引导骨再生膜。     

活性纳米羟基磷灰石复合胶原／聚乳酸材料应用于牙槽嵴扩增的研究

目的:构建下颌牙槽嵴扩增的动物模型,并初步观察nHAC/PLA复合rhBMP-2在下颌皮质骨表面贴附式植骨的成骨能力。方法:制备AnHAC/PLA材料,将HAC/PLA、AnHAC/PLA材料分别植入新西兰兔下颌骨颊侧皮质骨表面,设计皮质骨颊侧制备沟槽的改良术式组,并与无沟槽的普通术式组对比,术后8周通过大体、X线、组织学观察来研究其牙槽骨加宽的能力。结果:AnHAC/PLA材料较nHAC/PLA材料更能良好的增加下颌骨的宽度,在皮质骨表面增加刻槽的改良术式能明显增加材料的成骨情况。结论:AnHAC/PLA材料可以有效地增加牙槽骨宽度。     

活性纳米羟基磷灰石复合胶原材料贴附式植骨的实验研究

目的:探讨活性纳米羟基磷灰石复合胶原材料(AnHAC)在皮质骨表面贴附式植骨的成骨速度及吸收速度。方法:54只新西兰大白兔根据植入颅骨表面的植入物不同分为:纳米羟基磷灰石复合胶原材料(nHAC)组、AnHAC组、羟基磷灰石(HA)组。材料植入后4、8、12周取材,行大体标本及组织学观察、测量新骨长入高度及材料吸收率。结果:AnHAC组材料的吸收率及新骨长入的高度最大,nHAC组次之,HA组最小。结论:AnHAC材料在新骨形成及生物降解方面均较nHAC及HA明显增强,且在皮质骨表面可保持植入材料的高度,有望应用于牙槽骨加高及加宽的治疗。     

磷酸钙骨水泥与骨形成蛋白复合修复即刻种植牙骨缺损的实验研究

目的：探讨磷酸钙骨水泥(CPC)与人重组骨形成蛋白-2(rhBMP-2)复合修复即刻种植牙骨缺损的效果，为其临床应用于种植牙骨缺损修复的可行性奠定理论基础。方法：在兔股骨大转子上模拟即刻种植模型，种植体周围骨缺损区植入CPC／rhBMP-2及CPC进行修复，通过X线片，骨密度测量及组织学检查，观察新骨形成情况和材料的微观结构变化以及新骨与种植体的关系。结果：CPC／-rhBMP-2复合物可以有效地修复即刻种植牙骨缺损，材料被逐渐降解吸收，新骨与种植体表面更早地结合。结论：CPC／rhBMP-2是一种比较理想的新型骨移植材料.     

牙种植体即刻种植骨愈合过程的组织学观察

目的：了解即刻种植体的骨愈合过程，验证即刻种植的可行性。方法：在１２只犬下颌前磨牙新鲜拔牙创内立即植入纯钛牙种植体，通过组织学光镜和扫描电镜观察术后２、４、６、８、１２周种植体周围骨缺损修复过程和种植体骨结合形成情况。结果：骨缺损区内血块首先机化，而后沿牙槽窝骨壁向中心方向逐渐骨化形成新骨。小于１ｍｍ骨缺损１２周内可完全修复，种植体骨结合形成；１ｍｍ以上骨缺损则不能完全修复。结论：即刻种植体周围骨缺损的修复和骨结合形成类似于拔牙创的愈合，大于１ｍｍ的骨缺损应争取植骨。     

应用生长因子-支架构建方式的组织工程方法再生牙周组织的实验研究

目的：观察评价生长因子-支架构建方式的组织工程方法对牙周组织再生修复的影响和意义，探讨纳米羟基磷灰石材料(nHAC)和重组人骨形成蛋白-2(rhBMP-2)用于牙周组织工程的可行性。方法：将rhBMP-2与nHAC复合植入动物人工牙周组织缺损，表面覆盖聚四氟乙烯(e-PTFE)膜，以卒白对照组和单纯GTR组作为对照。术后8周进行组织学观察和测量，分析评价其牙周组织的再生情况。结果：rhBMP-2-nHAC-膜复合植入组较空白对照组和单纯GTR组有更多的新生牙槽骨、新生牙周膜和新生牙骨质生成，且未见上皮长入。结论：应用生长因子-支架构建方式的牙周组织工程方法能更有效地促进牙周组织再生和重建，而rhBMP-2和nHAC有望用作牙周组织工程的生长因子和支架材料。     

Recombinant human bone morphogenetic protein-2 stimulation of bone formation around endosseous dental implants

BACKGROUND: Successful endosseous implant placement requires that the implant be stable in alveolar bone. In certain cases, the implant can be stabilized in native bone but some part of the implant is not covered by bone tissue. This often occurs during placement of implants into extraction sites or in areas where bone resorption has occurred and the ridge width is not sufficient to completely surround the implant. In those cases, the clinician usually employs a procedure to encourage bone formation. These procedures typically include a bone graft and/or membrane therapy. Recent advances have led to the isolation, cloning, and production of recombinant human proteins that stimulate bone formation. One of these bone morphogenetic proteins (rhBMP-2) has been extensively studied in animal models and is currently being tested in human clinical trials. METHODS: In this study, rhBMP-2 was tested using a collagen sponge carrier to stimulate bone formation in defects in the canine mandible around endosseous dental implants. Six animals had a total of 48 implants placed. rhBMP-2 with the collagen carrier was implanted around 24 of these, the remainder having only the collagen carrier placed. Half the sites were covered with a nonresorbable expanded polytetrafluoroethylene membrane. Histologic analysis was performed after 4 and 12 weeks. The area of new bone formed, percentage of bone-to-implant contact in the defect area, and percentage fill of the defect was calculated. RESULTS: The addition of rhBMP-2 resulted in significantly greater amounts of new bone area and percentage of bone-to-implant contact and with more percentage fill after 4 and 12 weeks of healing. The area of new bone formed was reduced after 4 weeks when a membrane was present but after 12 weeks, there was no significant difference between membrane and non-membrane treated sites. In some specimens, new bone was found coronal to the membranes, with rhBMP-2-treated sites having greater amounts than non-rhBMP-2-treated sites. CONCLUSIONS: These data demonstrate that a bone differentiation factor significantly stimulates bone formation in peri-implant bone defects in the canine mandible. In addition, bone-to-implant contact was significantly enhanced along the rough implant surface. Membrane-treated sites had less new bone formation after 4 weeks of healing but were similar to non-membrane sites after 12 weeks. These results demonstrate that rhBMP-2 can be used to stimulate bone growth both around and onto the surface of endosseous dental implants placed in sites with extended peri-implant osseous defects.     

Alveolar Bone Regeneration around Immediate Implants Using an Injectable nHAC/CSH Loaded with Autogenic Blood‐Acquired Mesenchymal Progenitor Cells: An Experimental Study in the Dog Mandible

Background: Lack of osseointegration between a dental implant and the walls of the alveolar bone is a common problem in immediate implantation. Injectable tissue‐engineered bone (ITB) may be an effective and minimally invasive solution to the problem. In this study, an injectable bone cement, nHAC/CSH, which consists of nano‐hydroxyapatite/collagen (nHAC) and calcium sulfate hemihydrate (CaSO₄.½H₂O; CSH) was investigated as a tissue‐engineered scaffold material with blood‐acquired mesenchymal progenitor cells (BMPC) as seeding cells. Purpose: The aim of the study was to assess the new bone formation around immediate dental implants using nHAC/CSH loaded with dog blood‐acquired mesenchymal progenitor cells (dBMPC) in a canine model. Materials and Methods: dBMPC were first isolated from peripheral blood of healthy adult dogs. Alizarin red and oil red O staining were then used to evaluate the potential of dBMPC to differentiate into bi‐lineage mesenchymal tissues in vitro. Four healthy mongrel dogs were used in this study. The alveolar bone defects around immediate implants of dogs were created. Each defect was randomly assigned to one of the following three groups: (1) the ITB group (dBMPC + nHAC/CSH); (2) injectable bone cement nHAC/CSH; or (3) no materials (controls). Methylene blue staining was used to examine the bone formation after 3 months. Results: Studies in vitro revealed that dBMPC could be induced to osteoblasts and adipocytes. The ITB group (dBMPC + nHAC/CSH) showed significantly more bone‐implant contact and bone density than either nHAC/CSH or control groups in the areas with peri‐implant defects 3 months after implantation. Conclusion: The results indicate that the ITB composed of nHAC/CSH and dBMPC may represent a useful strategy for the clinical reconstruction of bone defects around immediate implantation. However, further investigation is needed involving the use of human BMPC as well as possible use of stem cells.     

The effect of rhBMP-2 around endosseous implants with and without membranes in the canine model

BACKGROUND: Bone morphogenetic protein (BMP) is a potent differentiating agent for cells of the osteoblastic lineage. It has been used in the oral cavity under a variety of indications and with different carriers. However, the optimal carrier for each indication is not known. This study examined a synthetic bioabsorbable carrier for BMP used in osseous defects around dental implants in the canine mandible. METHODS: Twelve canines had their mandibular four premolars and first molar teeth extracted bilaterally. After 5 months, four implants were placed with standardized circumferential defects around the coronal 4 mm of each implant. One-half of the defects received a polylactide/glycolide (PLGA) polymer carrier with or without recombinant human BMP-2 (rhBMP-2), and the other half received a collagen carrier with or without rhBMP-2. Additionally, one-half of the implants were covered with a non-resorbable (expanded polytetrafluoroethylene [ePTFE]) membrane to exclude soft tissues. Animals were sacrificed either 4 or 12 weeks later. Histomorphometric analysis included the percentage of new bone contact with the implant, the area of new bone, and the percentage of defect fill. This article describes results with the PLGA carrier. RESULTS: All implants demonstrated clinical and radiographic success with the amount of new bone formed dependent on the time and presence/absence of rhBMP-2 and presence/absence of a membrane. The percentage of bone-to-implant contact was greater with rhBMP-2, and after 12 weeks of healing, there was approximately one-third of the implant contacting bone in the defect site. After 4 weeks, the presence of a membrane appeared to slow new bone area formation. The percentage of fill in membrane-treated sites with rhBMP-2 rose from 24% fill to 42% after 4 and 12 weeks, respectively. Without rhBMP-2, the percentage of fill was 14% rising to 36% fill, respectively. CONCLUSIONS: After 4 weeks, the rhBMP-2-treated sites had a significantly higher percentage of contact, more new bone area, and higher percentage of defect fill than the sites without rhBMP-2. After 12 weeks, there was no significant difference in sites with or without rhBMP-2 regarding percentage of contact, new bone area, or percentage of defect fill. In regard to these three outcomes, comparing the results with this carrier to the results reported earlier with a collagen carrier in this study, only the area of new bone was significantly different with the collagen carrier resulting in greater bone than the PLGA carrier. Thus, the PLGA carrier for rhBMP-2 significantly stimulated bone formation around dental implants in this model after 1 month but not after 3 months of healing. The use of this growth factor and carrier combination appears to stimulate early bone healing events around the implants but not quite to the same degree as a collagen carrier.