【作者】 马毅慧；

【导师】 程祥荣； 张玉峰；

【作者基本信息】 武汉大学 ， 口腔修复学， 2013， 博士

【摘要】 研究背景和目的牙科种植体骨结合的发现被称为牙科种植体的转折点,近年来即刻负重由于其缩短了治疗时间、美学效果良好,同时解决了患者心理顾虑等问题,越来越受到关注。种植体负重成功最主要的前提就是初期稳定性,具有良好的初期稳定性为将来逐步负重奠定了良好的基础。传统理论认为考虑到骨组织的体积与密度,种植体的长度与宽度,通常要求在种植体植入3-6个月后才可以使种植体行使功能。初期稳定性差是种植失败的主要原因之一,其他失败原因包括感染、骨组织缺失和生物机械原理的过载。对于问题早期判断将有助于减少种植体失败,减轻患者痛苦。虽然建立良好的初期稳定性在种植体安放时就最早关注,但是这也存在许多其他因素影响种植体的初期稳固。因此,从骨组织开始吸收起保存种植体周围组织是十分重要的。然而实验研究和临床观察仍然存在许多问题。特别是即刻负重,初期稳定性和种植体周围成熟的骨组织对于长期的种植成功是具有决定意义的。本研究采用亲水性骨水泥作为种植体与骨组织之间的修复骨缺损,提高种植体初期稳定性的材料,获得了良好的种植体稳定性和较高的种植体最大旋出扭矩。众所周知,骨水泥作为一个骨科和矫形外科的传统材料,长期在临床中应用于髋关节置换或者椎体成形手术中,获得了良好和长期的临床疗效,临床中即刻种植经常遇到骨缺损较大,种植体初期稳定性差的情况,亲水化改造后的骨水泥可以有效充填骨缺损区,其较高的亲水能力可以增加骨水泥与骨组织之间的交联结构,最重要的是采用这种方式种植体可以获得非常好的初期稳定性,同时具有较大的旋出扭矩,为种植体即刻负重提供良好的基础。在第一部分实验中我们将亲水性的功能单体引入到传统骨水泥材料中,对传统骨水泥材料的机械强度和亲水性进行重新构造,希望可以改善传统骨水泥材料的亲水性和过高的弹性模量,然后使用MC3T3-E1细胞对骨水泥材料对骨细胞影响特征进行检测观察,并且相互比较。在第二部分试验中我们采用了新鲜的猪下颌骨,拔除前磨牙区的牙齿,将不同分组的骨水泥填入拔牙窝,同时插入预制的种植体,清理多余骨水泥材料,等待骨水泥完全固化,使用专用的扭矩测试仪器测量旋出种植体所需要的最大扭矩值。在获得良好的实验结果后,在亲水性骨水泥中选择一组骨水泥,在其中加入可降解材料—聚乳酸,通过在大鼠头骨上制备5mm直径圆形骨缺损,将骨水泥材料分别充填入骨缺损区,进行骨交联情况的观察。希望构建长期稳定的亲水性骨水泥,有利于牙科种植体长期持续负重,持续产生交联结构研究进行前期探索工作。研究方法在第一部分实验中我们使用亲水性功能单体丙烯酸、甲基丙烯酸羟乙酯,分成四个液体组：1、甲基丙烯酸甲酯单体(MMA)；2、甲基丙烯酸甲酯单体中加入20%(体积比)甲基丙烯酸羟乙酯(HEMA);3组：甲基丙烯酸甲酯单体中加入20%丙烯酸(AA)；4组：甲基丙烯酸甲酯单体中加入10%甲基丙烯酸羟乙酯和10%丙烯酸(HEMA+AA)。粉体为球形甲基丙烯酸甲酯,直径5um,平均分子量350,000。自行提纯制备的过氧化二苯甲酰(BPO)和N,N-二甲基对甲苯胺(DMPT)构成氧化还原体系。使用聚四氟乙烯模具制作统一标准著作各组实所需试件。采用衰减全反射傅里叶变换红外光谱了解材料中高分子化学键的变化规律,接触角测量仪检测改性后骨水泥的亲水能力和湿润性。在不同组分的骨水泥试件表面培养成骨样细胞(MC3T3-E1)。采用四唑盐(CCK-8)试剂盒检测细胞在骨水泥表面的粘附能力和增殖活性；罗丹明-鬼笔环肽免疫荧光染色检测细胞伸展和活力。第二部分实验,使用实验中的四个分组实验骨水泥进行牙种植体即刻负重的实验观察。收集新鲜的猪下颌骨,清除软组织,采用“微创”方式拔除前磨牙区的牙齿,在牙槽窝中充填骨水泥,同时插入预制的牙科种植体,清理多余骨水泥,等待骨水泥完全固化后使用专用的扭矩测试仪器,测试旋出种植体所需的最大扭矩值。为了构建可持续,降解可控制型的新型骨水泥,在上述实验基础上选择实验二组骨水泥(20%HEMA组),在其中加入可降解材料一聚乳酸。通过对大鼠头骨的5mm直径圆形骨缺损区进行骨缺损修复,进一步观察骨交联形成情况,并记录结果。研究结果加入亲水性功能单体的三个组的骨水泥通过接触角测试系统(OCA20)的检测,表面亲水性均有所提高,其中20%丙烯酸(AA)组的表面亲水性最好,明显优于其他三组骨水泥材料。在机械强度测试中,亲水性功能单体的引入使得传统丙烯酸骨水泥的弹性模量有所降低,这种变化有利于在种植体与颌骨松质骨之间建立应力弹性缓冲带,减少咬合力在种植体上产生的应力,进而引起骨吸收。细胞学试验结果显示,亲水性功能集团并没有改变传统丙烯酸骨水泥对骨细胞的影响作用,其安全性没有改变,在后期试验中将进一步增加骨水泥材料对骨细胞有利作用方面的改进。通过旋出扭矩测试可以获知,亲水性丙烯酸骨水泥可以极大地提高种植体的初期稳定性,并且获得很好的旋出扭矩,使得牙科种植体即刻负重成为可能,在未来的实验中将进一步观察负重后的效果。更多还原

【Abstract】 Background and objectiveDental implant osseointegration finding known as the turning point of dental implant with immediate loading, in recent years due to shorten treatment time, aesthetics, and solve the problems such as anxiety, more and more attention. Implant loading success the most important precondition is the initial stability, has a good primary stability has laid a good foundation for the future progressive weight-bearing. According to traditional theory considering the volume and density of bone tissue, the width and length of the implant, usually require implants in3-6months after the implant function. The initial stability is one of the main causes of implant failure, overload other failure causes include infection, bone loss and biological mechanics. For the problem of early judgment will help to reduce the failure of implant, to alleviate the suffering of patients.Although the establishment of good primary stability of implant placed in when he was concerned, but it also has many other primary factors influencing implant. Therefore, from the beginning of bone absorption of preservation of peri-implant tissue is very important. However, the experimental study and clinical observation of the many problems still exist. Especially the immediate loading, bone tissue around the implant stability and maturity of the initial success is crucial to the long-term planting.This study adopts hydrophilic bone cement for the repair of bone defect between implant and bone tissue, improve the stability of the early planting material body, has obtained the good implant stability and higher implant maximum rotary torque. As everyone knows, bone cement as traditional materials a department of orthopedics and orthopaedics, long in the clinical application to hip replacement or centrum forming operation, get a good and long-term clinical efficacy, clinical in immediate implant often encountered in larger bone defects, implants of bone cement, hydrophilic after transformation can effectively filling the bone defect area, its high hydrophilic ability can be cross-linked structure between bone cement and bone tissue increased, the most important is the use of this implant can obtain very good primary stability, with larger rotation torque, provide a good foundation for the implant with immediate loading.In the first part of the experiment we will hydrophilic functional monomer was introduced to the traditional bone cement materials, to reconstruct the traditional bone cement material mechanical strength and hydrophilicity. hope to improve the traditional bone cement material hydrophilicity and high modulus of elasticity, and then use the MC3T3-E1cells were detected to observe the influence of characteristics of bone cement material of bone cells, and compared with each other.In the second part test we used fresh porcine mandibular premolars extraction area, teeth, bone cement of different groups into the socket, and inserted into the implant prefabricated, clean up excess bone cement material, wait for the bone cement is completely cured, use the special torque test instrument to measure the spin out the maximum torque of planting body required values. To obtain good experimental results, select a group of bone cement in the hydrophilic bone cement, adding the biodegradable material, poly lactic acid, through the preparation of5mm diameter circular bone defects in the rat skull, the bone cement filling bone defects respectively, were observed in the bone crosslinking. Hope to build long-term stability of the hydrophilic bone cement, is conducive to the dental implant long-term sustained loading, continue to produce preliminary exploration of crosslinking structure.Research methodsIn the first part of the experiment we use hydrophilic functional monomer acrylic acid, methyl methacrylate, divided into four groups:liquid1, methyl methacrylate monomer (MMA);2, methyl methacrylate monomer addition of20%(volume ratio) of2-hydroxyethyl methacrylate (HEMA); group3:methyl methacrylate the addition of20%acrylic acid monomer (AA); group4:methyl methacrylate monomer with10%hydroxyethyl methacrylate and acrylic acid (HEMA+AA)10%. Powder is spherical methyl methacrylate, diameter5um, average molecular weight of350000. Self purification two benzoyl peroxide prepared (BPO) and N, N-two methyl aniline (DMPT) constitute a redox system. The use of Teflon mold production standard work groups is needed specimen. Attenuated total reflection Fourier transform infrared spectroscopy to understand the changes of chemical bonds in the polymer materials, contact angle measuring instrument detection modified hydrophilic ability and wettability of bone cement. The specimen surface cultured osteoblast-like cells in bone cement with different composition (MC3T3-E1). For detection of cell adhesion and proliferation activity in bone cement surface with CCK-8kits; Luo Danming-phalloidin staining detection cell spreading and vitality.The second part of the experiment, four experimental groups have been used for immediate loading of dental implants, in the. The collection of fresh pig mandible, clear and soft tissue, using "minimally invasive" means premolar extraction area of the tooth socket, in filling bone cement, while inserting dental implants prefabricated, clean up excess bone cement, waiting for the torque testing instrument of bone cement is completely solidified using a dedicated, test spin out the maximum torque of planting body desired value. In order to build a sustainable, novel degradation can control the type of cement, selection of experimental group two bone cement on the basis of the above experiment (group20%HEMA), adding the biodegradable material, poly lactic acid. For the repair of bone defects of rats by skull5mm diameter circular bone defect area, further observation of bone crosslink formation, and record the results.The resultsThe three group of bone cement adding hydrophilic functional monomer by contact angle measurement system (OCA20) detection, has surface hydrophilicity improved, including20%acrylic acid (AA) surface hydrophilic group is the best, significantly better than the other three groups of bone cement.In the mechanical strength test, the hydrophilic into monomers makes traditional elastic modulus of acrylic bone cement has been reduced, this change is conducive to the implant and bone and cancellous bone is established between the elastic stress buffer zone, reduce the bite resultant stress generated in the implants, and caused bone resorption.Cytological test results show, a hydrophilic functional group did not change the traditional acrylic bone cement effects on bone cells, its security has not changed, further improvement of bone cement material beneficial effect on bone cells in the later test.By adjusting the torque testing can be informed, hydrophilic acrylic bone cement can greatly increase the primary stability of the implants, and obtain good rotation torque, the dental implant with immediate loading possible, further observation after loading effect in the future.更多还原