胶原基纳米骨复合重组人骨形成蛋白2及钛膜修复即刻钛种植体周围骨缺损

背景:影响即刻种植术成功的主要因素是种植体大小、形状往往与拔牙创不相适合,不能形成种植体与拔牙创的紧密接触,解决这一影响因素的方法多采用诱导骨再生膜技术或应用植骨材料.目的:观察胶原基纳米骨(nanohydroxyapatite/collogen,nHAC)复合重组入骨形成蚩白2(recombinant human bone morphogenetic protein-2,rhBMP-2)及钛膜修复即刻钛种植体周围骨缺损的效果.设计、时间及地点:随机对照动物实验,于2005-01/2006-01在解放军第四军医大学中心实验室完成.材料:宝鸡有色金属研究院提供的纯钛材料制成直径2mm,长10mm,螺距0.4mm,带自攻式螺纹的钉状螺旋种植体,无穿龈部分.西安中邦钛生物材料有限公司生产的不可吸收医用钛膜,大小为2 cm×2cm.胶原基纳米骨由清华大学崔福斋教授惠赠,加工成0.5 mm×0.5 mm×0.5 mm的立方体.rhBMP-2由北京军事医学科学院提供.将rhBMP-2用盐酸胍溶解,将制备好的胶原基纳米骨浸入其中,抽真空,冻干,每粒胶原基纳米骨约复合1 mg rhBMP-2.方法:选用健康雄性Beagle纯种犬4只,钛种植体周围骨缺损的修复方法分为以下6组:①阳性对照组植入自体牙槽松质骨.②空白对照组缺损区不植入任何物质,只覆盖钛膜.③nHAC组仪植入nHAC.④nHAC+钛膜组植入nHAC,表面覆盖钛膜.⑤nHAC+mBMP-2组植入nHAC复合rhBMP-2材料.⑥nHAC+rhBMP-2+钛膜组植入nHAC复合rhBMP-2材料,表面覆盖钛膜.每只动物的每侧下颌骨各形成6个缺损区,将6组材料随机植入.主要观察指标:术后6,12周,采用X射线摄片、骨密度测量及组织学检查,观察新骨形成情况和新骨与种植体的关系.结果:12周时各组骨缺损区均愈合良好,骨创均由新生骨所充满,种植体稳固,骨整合良好.nHAC+mBMP-2组及nHAC+nhBMP-2+钛膜组成骨较早,骨成熟较早.nHAC+钛膜组、空白对照组、nHAC+mBMP-2+钛膜组,钛膜下骨生成较好,牙槽嵴较丰满.nHAC+rhBMP-2+钛膜组不但成骨较早,骨形成量最多,而且牙槽嵴最为丰满,12周时骨密度已与阳性对照组一致,但较自体骨移植牙槽嵴更丰满,成骨量更多.空白对照组成骨最慢,阳性对照组成骨最快,但牙槽嵴顶稍有吸收.结论:nHAC具有良好的骨引导作用,修复种植体周骨缺损较好,复合rhBMP-2或/和钛膜后效果更佳.临床上可根据具体情况选用修复即刻种植体周围骨缺损的方法.

Nano-hydroxyapatite/collagen composited with recombinant human bone morphogenetic protein-2 and titanium membrane in repairing peripheral bone defects of instant dental implants

BACKGROUND:Recently,with the rapid development of material science and bioscience,the technology of dental implant has made great progress,especially the immediate implant technology.But the size and shape of implant are usually not fit for tooth extraction wound,so it is an important factor that leads to failure when implant and tooth extraction wound can not form close tangency.Guided bone regeneration or bone grafting materials are usually used to solve this problem.OBJECTIVE:To study the effects of nano-hydroxyapatite/collogen (nHAC) with recombinant human bone morphogenetic protein-2(rhBMP-2) and titanium (Ti) membrane on repairing peripheral bone defects of instant implant.DESIGN,TIME AND SETTING:A randomized,controlled animal study was performed at the Central Laboratory,the Fourth Military Medical University of Chinese PLA between January 2005 and January 2006.MATERIALS:Ti screw implants (diameter 2 mm,length 10 mm,and pitch 0.4 mm) without the part that went through gum were offered by Nonferrous Metal Academy in Baoji,China.The nonabsorbable Ti membranes (2 cm×2 cm) were offered by Zhongbang Biomaterial Limited Company in Xi'an,China.The nHAC materials were gifted by professor Cui Fu-zhai from Material Science and Engineering Department of Tsinghua University and fabricated into 0.5 mm×0.5 mm×0.5 mm small blocks.rhBMP-2 was offered by the Academy of Military Medical Sciences in Beijing,China.rhBMP-2 was dissolved with hydrochloric carbamidine and then nHAC was immersed in it.Vacuumization,freeze-drying,and Ekibon degermation were followed.Each gram of nHAC compounds required approximately 1 mg rhBMP-2.METHODS:Four healthy purebred male dogs were included in this study.According to the methods to repair bone defects rhBMP-2+Ti membrane,nHAC composited with rhBMP-2 was implanted,covering Ti membrane.Six defects were made on the mandible on each side.MAIN OUTCOME MEASURES:At 6 and 12 weeks after implantation,new bone formation and the correlation of new bone to Ti implant were investigated by radiography,bone density measurement and histological examinations.RESULTS:All the bone wounds were full of new bone at 12 weeks,the Ti implants were steady and the osseointegration was good.In the nHAC+rhBMP-2 and nHAC+rhBMP-2+Ti membrane groups,new bone formed and maturated earlier.In the nHAC +Ti membrane,blank control,and nHAC + rhBMP-2 +Ti membrane groups,new bone formed well below Ti membrane and the alveolar crest was plump.In the nHAC + rhBMP-2 +Ti membrane group,new bone formed earliest with the most quantity and the alveolar crest was the plumpest.By 12 weeks,the bone density had achieved the same level as the autologous cancellous bone transplantation,but the alveolar crest was plumper compared to the positive control group.In addition,bone mass was much more.Bone formed slowest in the blank control group and fastest in the positive control group with the crest of ridge being slightly absorbed.CONCLUSION:nHAC is a new good bone graft material in repairing peripheral bone defects of instant implant,especially compositing with rhBMP-2 and/or Ti membrane.A round method to repair the surrounding bone defect of instant implant should be selected according to the specific situation in the clinic.