生物功能牙种植体表面构建与临床研究

发布时间：2018-06-25 12:28

本文选题：种植体设计 + 三维有限元分析　；参考：《华南理工大学》2014年博士论文

【摘要】：牙种植体的生物力学相容性和组织相容性是实现义齿种植成功和长期稳定性的基础。因此，牙种植体的设计过程中不仅要根据载荷条件选择材料学性能和加工性能适配的材料，设计种植体及其基台的形状、长度、直径和连接方式等，同时还需要系统研究牙种植体表面仿生结构的构建及其与细胞之间的相互作用机制。本研究通过表面改性技术构建结构合理、力学性能优良、具有模拟骨细胞外基质骨架的表面微纳米拓扑结构和骨整合性能优异的钙磷涂层钛基牙种植体。通过体外仿生矿化实验、蛋白吸附和动物体内植入实验系统研究经不同表面处理的种植体的体内、外成骨性能，在此基础上对等离子喷涂钙磷涂层牙种植体进行前瞻性临床实验研究，为设计和制备满足临床应用需求的长期稳定的新型表面改性钛合金牙种植体提供参考。根据机械力学、生物力学原理，结合中国人牙及颌骨的解剖特点，设计出面向临床应用的牙种植体系统。该牙种植体系统具有圆柱和螺纹两种形态，5种直径和5种长度规格，基台和种植体连接采用7莫氏锥度，360度旋转定位和平台转移结构。基台4、5、6、7及8锥度内连接在35N·cm的预载力作用下,基台与种植体之间存在冷焊现象，表现为脱位力矩大于预载力矩5%-10%，且各锥度之间无明显差异，而超过40N·cm的力矩，将破坏界面的冷焊结合。三维有限元分析发现，4-8不同锥度连接的基台在垂直和水平加载的情况下，应力分布相似，应力集中区均在种植体和基台连接的颈部，且随锥度的增大，应力值呈线性减小。水平向加载的应力及应变位移均明显高于垂直加载，说明水平向的载荷更易对种植体结构产生破坏作用；0、15和45肩台斜面设计的种植体连接7锥度的基台，在垂直加载和水平加载情况下，它们之间应力分布在种植体结构间及与周围颌骨之间差异不大。特别的是水平加载时皮质骨最大应力值与垂直加载之间无明显差异，而松质骨内的应力与垂直加载相比虽有约1.5倍的增大，但位置明显移至种植体的根部，表明平台转移可有效地减少种植体颈部周围骨的应力集中，从而减少种植体周围骨的吸收，利于种植修复的长期成功。采用喷砂-酸蚀处理技术对钛基种植体表面进行处理，系统研究了酸的种类以及酸蚀时间对于表面微纳米粗糙度、表面亲疏水性、表面成分等的影响规律。通过控制酸蚀时间和酸的种类实现了表面微纳米拓扑结构的调控，其中在HCl/H2SO4混合溶液中酸蚀处理的钛基种植体样品表面形成了具有多级尺度的拓扑结构，即由1～2μm的小孔组成的直径10～20μm的腐蚀坑。这种表面微纳米拓扑结构是晶界腐蚀与点蚀共同作用的结果。通过喷砂-酸蚀构建的仿生多级拓扑结构可模拟细胞外基质的物理信号刺激，促进粘附、增殖、分化等细胞行为，有利于加速骨整合过程。种植体的骨整合性能对其初期稳定非常重要，本研究采用等离子喷涂技术在钛基种植体表面构建钙磷生物活性涂层。系统研究了包括喷涂功率、粉体粒径以及喷涂距离对涂层致密度、涂层表面形貌以及涂层中的物相组成的影响规律。结果表明：在喷涂功率30kW、喷涂距离110mm、HA粉末粒度为20～50μm时所制备的表面涂层致密度高、性能优异。从热力学上系统分析了等离子喷涂过程中可能出现的钙磷盐物相转变过程。将喷砂-酸蚀处理样品和等离子喷涂钙磷涂层样品浸入模拟体液6天后，均可见表面有磷灰石层沉积，利用扫描电镜、X射线衍射、红外光谱和能谱对表面沉积物进行分析表明，喷砂-酸蚀钛种植体样品表面生成的是非晶态绒球状磷酸钙，而等离子喷涂种植体样品表面在短时间内沉积出较厚、结晶度较高的磷灰石层。此外，蛋白吸附的定性和定量分析结果表明喷砂-酸蚀以及等离子喷涂钙磷涂层样品表面可以显著促进蛋白的吸附。对经两种表面处理的钛基种植体进行了兔腿骨内种植实验。结果表明，两种种植体都可以与骨组织发生紧密的骨性结合，显著提高种植体与骨组织之间的结合力，促进骨组织的形成。在此基础上临床实验研究表明，72个病例均无肝肾功能改变及并发症的发生，共计植入117颗种植体3年临床实验期间种植体生存率达99.2%，一期术后及二期手术检查种植体周垂直骨丧失平均为0.07mm，，修复后1-3年全景X光片测量骨吸收平均值为0.14mm，种植体周围指数及牙龈指数无明显变化，表明种植体周围软组织健康稳定。临床研究表明生物功能牙种植体能与牙槽骨形成良好的骨整合，种植系统的结构设计和表面构建有利于减少种植体周骨组织的吸收，并保持种植体周软组织的健康和软组织的量。本论文阐述了牙种植体发展应用现状，对种植体的临床应用和长期成功的关键因素种植体表面生物功能构建和结构形态设计进行了系统研究，经多年研发、动物实验和临床试验证明生物功能牙种植体的安全性和有效性。
[Abstract]:The biomechanical compatibility and histocompatibility of dental implants are the basis for the success and long-term stability of denture implant. Therefore, the design process of dental implants is not only to choose material of material properties and processing properties according to the load conditions, but also to design the shape, length, diameter and connection mode of the implant and its base. The construction of biomimetic structure on the surface of dental implants and the interaction mechanism between the dental implants and the cells are also needed to be studied systematically. The surface modification technology is used to construct a reasonable structure with excellent mechanical properties. The surface micro and nano topology with the skeleton of the bone extracellular matrix and the implantation of calcium and phosphorus coated titanium abutments with excellent bone integration properties are cultivated. Through in vitro biomimetic mineralization experiments, protein adsorption and animal body implantation experimental system to study the internal and external osteogenesis of different surface treated implants, the plasma sprayed calcium phosphorus coated dental implant was prospectively studied in order to design and prepare a long-term stable new clinical application. The reference is provided for the dental implants of type surface modified titanium alloy.
According to the mechanical mechanics and biomechanics principle, combined with the anatomical characteristics of the Chinese tooth and jaw, the dental implant system is designed to be applied to the clinic. The dental implant system has two forms of cylinder and thread, 5 diameters and 5 length specifications, 7 moth taper, 360 degree rotation positioning and platform transfer structure connecting the base and the implant. There is a cold welding phenomenon between the base platform and the implant under the preloading force of the base platform 4,5,6,7 and the 8 taper under the preloading force of 35N cm. It shows that the dislocation moment is greater than the preload torque 5%-10%, and there is no obvious difference between the taper degrees, and the cold welding of the interface is combined with the moment of 40N. Cm. The three dimensional finite element analysis found that the base of 4-8 different taper connection bases is found. In the case of vertical and horizontal loading, the stress distribution is similar, the stress concentration area is both in the neck of the implant and the base platform, and with the increase of the taper, the stress value decreases linearly. The stress and strain displacement of horizontal loading are obviously higher than that of the vertical loading, which indicates that the horizontal load is more vulnerable to the damage of the implant structure; 0, The 15 and 45 shoulder slope surfaces were designed to connect the base of the 7 taper. Under vertical loading and horizontal loading, the stress distribution between the implant structures and the surrounding jaws was not significant. Although the vertical loading is about 1.5 times larger, the position is obviously moved to the root of the implant. It shows that the platform transfer can effectively reduce the stress concentration around the bone around the neck of the implant, thus reducing the absorption of the bone around the implant, and is beneficial to the long-term success of the implant.
The surface of titanium based implant was treated with sand blasting and acid etching treatment. The effects of acid species and etching time on surface micro and nano roughness, surface hydrophobicity and surface composition were studied. The surface micro and nano topology was controlled by controlling the etching time and the type of acid, in which HCl/H2SO4 The surface of the titanium base implants treated with acid etching in the mixed solution formed a multi-scale topology, that is, a corrosion pit with a diameter of 10~20 micron, consisting of a small hole of 1~2 mu m. This surface micro and nano topology is the result of the interaction of grain boundary corrosion and pitting. The physical signal stimulation of extracellular matrix promotes cell adhesion, proliferation, differentiation and other cell behaviors, and accelerates the osseointegration process.
The bone integration performance of the implant is very important for its initial stability. In this study, the plasma spraying technology was used to construct calcium and phosphorus bioactive coating on the surface of titanium implants. The effects of spraying power, particle size and spray distance on the density of the coating, the surface appearance of the coating and the composition of the phase in the coating were systematically studied. The results show that the surface coating produced by spraying power 30kW, spraying distance 110mm and HA powder size of 20~50 u m has high density and excellent performance. The phase transition process of calcium phosphorus salts may appear in the process of plasma spraying. After 6 days of simulated body fluid, apatite layer was deposited on the surface, and the surface sediments were analyzed by scanning electron microscope (SEM), X ray diffraction, infrared spectrum and energy spectrum. The results showed that the surface of the sample surface of the sanding and acid etching titanium implant was amorphous calcium phosphate, and the surface of the plasma sprayed implant sample deposited in a short time. In addition, the qualitative and quantitative analysis results of protein adsorption show that the surface of sand and acid erosion and the surface of plasma sprayed calcium and phosphorus coating can significantly promote the adsorption of protein.
Two kinds of surface treated titanium implants were planted in the rabbit's leg bone planting experiment. The results showed that the two implants could combine bone tissue closely with bone tissue, significantly increase the binding force between the implant and bone tissue, and promote the formation of bone tissue. On this basis, the experimental study showed that both of the 72 cases had no liver and kidney function. The survival rate of the implant was 99.2% during the 3 year clinical trial of 117 implants. The average of the periimplant bone loss was 0.07mm after the first stage and two stage operation. The average bone absorption of the panoramic X ray after 1-3 year restoration was 0.14mm, the periimplant index and gingival index were not changed obviously. The soft tissue around the implants is healthy and stable. The clinical study shows that the biofunctional dental implant can form a good bone integration with the alveolar bone. The structural design and surface construction of the implant system are beneficial to reduce the absorption of the periimplant bone tissue and maintain the healthy and soft tissue of the soft tissue of the implant.
This paper describes the development and application status of dental implants. The clinical application of implant and the key factors for long-term success are studied systematically. After years of research and development, animal experiments and clinical trials have proved the safety and effectiveness of biological functional dental implant.
【学位授予单位】：华南理工大学
【学位级别】：博士
【学位授予年份】：2014
【分类号】：R783.6

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