表面粗化处理不均衡螺纹钛人工牙种植体的生物学性能研究

发布时间：2017-12-26 21:30

本文关键词：表面粗化处理不均衡螺纹钛人工牙种植体的生物学性能研究　出处：《河北医科大学》2017年博士论文　论文类型：学位论文

【摘要】：第一部分不均衡螺纹钛人工牙种植体的三维有限元应力分析目的:在种植体生物力学优化设计中螺纹形态扮演了非常重要的角色,它可以增加种植体-骨接触面积,提高种植体初始稳定性,改善骨界面的应力分布。目前骨内种植体表面螺纹多采用均衡分布的单一螺纹,而针对骨皮质区采用节距及深度较小的微螺纹、骨松质区采用节距相对较宽的螺纹,有文献证实这种不均衡螺纹设计有较好的力学效应,但是对于颈部不同微螺纹的生物力学特性很少有报道。正确设计种植体的形状,使种植体与骨组织之间的界面上受力尽量趋于合理,尤其是降低颈部皮质骨上缘处的应力集中,将有助于减少骨吸收,降低种植体发生松动的可能性,延长其使用寿命。为提高种植修复的远期成功率,有必要进行种植体螺纹的优化设计,尤其是颈部微螺纹结构的优化及螺纹的优化组合。本实验旨在探讨不同颈部螺纹外形设计种植体的生物力学性能。方法:1种植体分组四种不同颈部形态分为均衡螺纹组、宽颈组、颈部单头微螺纹组、颈部双头微螺纹组。2下颌骨模型2.1初步建模依据头颅CT扫描图像,在Mimics 16.0中建立对应新项目。根据CT图像灰度值将骨质部分提取出来,对骨质物蒙罩进行编辑,得到精确的仅包括下颌骨像素点的无空隙蒙罩模型,由蒙罩内像素点自动计算三维模型,将最终生成的下颌骨初步三维几何模型以STL(Standard Template Library)格式输出。2.2模型优化将STL格式的下颌骨初步三维模型导入到Geomagic studio 2013中,采用多次快速光顺将模型初步光滑化,改善多边形曲面性能,获得下颌骨多边形模型,转到精确曲面阶段,获得下颌骨曲面片模型。经过CAD对象转换,最终得到下颌骨CAD模型。2.3生成皮质骨与松质骨在Geomagic多边形阶段,通过向内1.5mm抽壳并删除交叉面得到下颌骨的皮质骨与松质骨交界面的多边形模型,再按上述步骤逐步操作得到以交界面为外轮廓的松质骨CAD模型。将已得到的下颌骨整体CAD模型和松骨质CAD模型导入到Solidworks 2015中,由布尔减操作,即得到皮质骨模型。2.4种植体与下颌骨的装配分别将四组种植体置于下颌骨第一磨牙区某一相同位置,由Solidworks在种植体顶部建立高度为3.2mm的基台,在其上建立顶端为2mm厚度的瓷修复体。将其以sat格式导入Ansys Workbench 14.5中。2.5网格划分采用以六面体为主四面体为辅的自动网格划分方法,单元大小约为0.5mm,在种植体及其附近节点和单元适当加密。2.6材料属性及约束所有材料假设为均质各向同性的线弹性材料,材料变形为弹性小变形。将下颌骨两侧髁突顶端所有节点自由度予以刚性约束;种植体与骨组织为100%骨结合;瓷修复体和种植体之间为固定接触。2.7加载条件分别施加以下三种载荷工况的均布载荷:轴向100N、由颊侧向舌侧水平50N、与种植体轴线成30°由唇颊侧指向舌侧向下100N。2.8评价指标分析Von-Mises等效应力和最大主应力。结果:1种植体-骨界面应力分布总的特征种植体颈部不同特征对种植体-骨界面应力值、应力分布有明显影响;整体应力集中区域均位于种植体的颈部及种植体根尖部。2轴向加载100牛顿时对于均衡螺纹组、宽颈组、颈部单头微螺纹组、颈部双头微螺纹组而言,皮质骨区等效应力最大值分别为46.58MPa、35.25MPa、20.98MPa、58.01MPa,松质骨区等效应力最大值分别为3.64MPa、7.45MPa、2.60MPa、12.38MPa。对于这四组种植体而言,在皮质骨上缘处的最大主应力值分别为0.97MPa、0.89MPa、0.79MPa、1.22MPa;在皮质骨与松质骨交界处的最大主应力值分别为1.72MPa、3.89MPa、0.45MPa、8.07MPa;在种植体的末端处的最大主应力值分别为0.73MPa、0.67MPa、0.64MPa、0.57MPa;四组种植体在松质骨区中段位点的最大主应力值均表现为较低水平。3颊舌向水平加载50牛顿时对于均衡螺纹组、宽颈组、颈部单头微螺纹组、颈部双头微螺纹组而言,皮质骨区等效应力最大值分别为53.21MPa、41.93MPa、36.95MPa、64.18MPa,松质骨区等效应力最大值分别为3.72MPa、6.57MPa、3.77MPa、4.07MPa。对于这四组种植体而言,在皮质骨上缘处的最大主应力值分别为41.77MPa、39.61MPa、29.67MPa、46.99MPa;在皮质骨与松质骨交界处的最大主应力值分别为9.45MPa、2.80MPa、1.73MPa、9.49MPa;在种植体的末端处的最大主应力值分别为0.07MPa、0.09MPa、0.15MPa、0.26MPa;四组种植体在皮质骨区的最大主应力值均表现为较高水平。4斜向加载100牛顿时对于均衡螺纹组、宽颈组、颈部单头微螺纹组、颈部双头微螺纹组而言,皮质骨区等效应力最大值分别为49.37MPa、47.78MPa、34.02MPa、78.52MPa,松质骨区等效应力最大值分别为3.74MPa、3.72MPa、3.81MPa、7.33MPa。对于这四组种植体而言,在皮质骨上缘处的最大主应力值分别为29.35MPa、21.28MPa、15.34MPa、34.69MPa;在皮质骨与松质骨交界处的最大主应力值分别为3.50MPa、2.71MPa、0.97MPa、8.58MPa;在种植体的末端处的最大主应力值分别为0.16MPa、0.11MPa、0.15MPa、0.10MPa;四组种植体在皮质骨区的最大主应力值均表现为较高水平。第二部分表面粗化处理不均衡螺纹钛人工牙种植体的疲劳性能研究目的:人工牙种植体的材料及其表面性状、形态是影响骨整合的重要因素。喷砂+酸蚀表面处理技术是一种新型非涂层钛牙种植体表面改性方法。经该方法处理的钛种植体表面,其形貌特征发生了明显的改变,不仅使其表面的粗糙度明显提高,且优化了种植体表面的超微结构;酸化处理后,大的孔洞中形成了无数微小的二级窝洞,这对提高骨组织与种植体表面之间的机械锁合有重要的意义。钛颗粒喷砂消除了异种元素的污染,HCL/H2SO4混合酸热处理喷砂后的表面,获得了较为理想的表面形貌特征,但该物理、化学处理工艺对种植体疲劳性能的影响程度如何,未见有报道。本实验旨在探讨种植体不同颈部螺纹外形设计及表面粗化处理对力学疲劳性能的影响。方法:1种植体分组分为均衡螺纹组、宽颈组、颈部单头微螺纹组、颈部双头微螺纹组、表面粗化及颈部双头微螺纹组。2表面形貌观察颈部双头微螺纹组、表面粗化及颈部双头微螺纹组经FSEM观察分析种植体表层的结构、形貌。3疲劳试验3.1试验标准依据IS014801:2007加载3.2试验环境在空气中进行,温度20±5℃3.3载荷波形和频率采用单向载荷,载荷在标称峰值和10%标称峰值之间呈正弦曲线变化;载荷频率为15Hz。3.4步骤3.4.1种植体各组件的组装下部结构、基台通过内六方连接,由中央螺栓紧固8-10Ncm。3.4.2半球形承载部件的粘接3.4.3种植体的包埋及固定3.4.4连接INSTRON电子动静态万能材料试验机3.4.5初始载荷为静态载荷值的80%,随后依次降低,每个试验组至少测试四个不同载荷,直至达到5×10~6循环时测得的最大耐受,在此载荷下三个试件完好。3.4.6计算施加的最大弯矩3.4.7记录在各载荷下的循环次数及位移,比较在同一加载力值下达到5×10~6循环的位移。结果:1表面形貌观察颈部双头微螺纹组的Ma表面,肉眼观:表面光滑、洁净,色泽均匀发亮呈金属银白色。FSEM观察:低倍电镜下,表面平整、微粗糙,可见方向一致的条纹。300倍电镜下,表面较多平行排列的切削沟纹,微粗糙;千倍以上电镜下可以看到表面较平整,有大量方向一致的、规则的、浅沟纹状的切削条痕,局部散在点状凹陷及凸起。表面粗化及颈部双头微螺纹组的SLA粗化表面,肉眼观:表面粗糙,不见金属色泽,呈均匀的灰白色。FSEM观察:低倍电镜下,表面整洁、粗糙均匀;300倍电镜下,呈现不规则的粗糙表面,可见浅凹及小的裂隙;千倍电镜下可见不规则的凹陷表面上有大量大小不一的微孔;微孔大小为5-30um,边缘锐利,相邻微孔部分融合,偶尔可见散在的微裂隙;万倍电镜下,在大的窝洞、凹陷内还可以看到大量形状不规则的小的凹坑,约200-500nm,大小、深浅不一,洞底为半圆形,边缘圆钝。2动态循环疲劳性能2.1种植体达到5×10~6循环的极限载荷及最大弯矩均衡螺纹组、宽颈组、颈部单头微螺纹组、颈部双头微螺纹组、表面粗化及颈部双头微螺纹组种植体达到5×10~6循环的极限载荷值分别为250N、300N、300N、300N、275N;对应的最大弯矩为137.50Ncm、165.00Ncm、165.00Ncm、165.00Ncm、151.25Ncm。2.2种植体动态疲劳位移均衡螺纹组、宽颈组、颈部单头微螺纹组、颈部双头微螺纹组、表面粗化及颈部双头微螺纹组种植体在250N载荷下,达到5×10~6循环时,对应的位移分别为0.391mm、0.251mm、0.257mm、0.258mm、0.272mm。第三部分表面粗化处理不均衡螺纹钛人工牙种植体的骨结合性能研究目的:实验一探讨了种植体不同颈部外形对应力分布的影响,实验二探讨了种植体不同颈部螺纹外形设计及表面粗化处理对力学疲劳性能的影响。本研究旨在探讨种植体不同颈部螺纹外形设计及表面粗化处理对骨结合性能的影响,为优化种植体颈部微螺纹结构及粗化表面设计提供较为完整的实验依据。方法:1实验动物分组成年新西兰大白兔90只,雄性,随机分为五组,均衡螺纹组、宽颈组、颈部单头微螺纹组、颈部双头微螺纹组、表面粗化及颈部双头微螺纹组,每组18只。2种植体植入手术动物术前6小时禁食、禁饮,1%戊巴比妥钠注射液经耳缘静脉麻醉;在兔股骨的远心末端术区备皮,消毒,铺巾;用0.5%盐酸利多卡因注射液局部浸润麻醉;依次切开皮肤、筋膜和骨膜,剥离骨膜暴露骨面,用系列扩孔钻依次制备植入窝洞。将五组种植体随机植入每只动物的股骨远心末端,植入扭矩10Ncm,植入体顶端与骨面平齐,创口局部用0.9%氯化钠注射液冲洗,依次缝合骨膜、筋膜、皮肤。3 X-ray平片观察术后12周时,拍摄X-ray平片观察五组标本的影像学特点。4旋出扭矩测试术后4周、8周和12周时,分别处死五组动物,取下带有种植体的股骨,采用便携式数字扭矩测试仪测量旋出种植体时的最大扭矩值。5种植体-骨界面的扫描电镜观察术后4周、8周和12周时,将颈部双头微螺纹组、表面粗化及颈部双头微螺纹组旋出的种植体固定、脱水、干燥、粘台、喷金,用FSEM观察种植体表面形貌特点。6种植体-骨界面的能谱分析术后4周、8周和12周时,将颈部双头微螺纹组、表面粗化及颈部双头微螺纹组旋出的种植体干燥、粘台、喷金,用EDX测试种植体-骨界面化学元素组成。7组织学观察将术后12周取下的颈部双头微螺纹组、表面粗化及颈部双头微螺纹组带有种植体的股骨标本脱矿制作组织切片,HE染色,观察骨结合情况。8统计学分析五组的旋出扭矩值采用SPSS20.0软件包处理,采用重复测量资料方差分析,P0.05时具有统计学意义。结果:1 X-ray平片观察术后12周时,各种植体周围界面无透射线性影像,与周围骨的密度比较相似;各种植体颈部周围未见明显骨吸收影响。2旋出扭矩在4、8、12周时,表面粗化及颈部双头微螺纹组的旋出扭矩值均较颈部双头微螺纹组高;颈部单头微螺纹组、颈部双头微螺纹组旋出扭矩值无明显差别,均高于均衡螺纹组、宽颈组的旋出扭矩值;宽颈组最低。3 FSEM观察3.1术后4周颈部双头微螺纹组种植体表面覆盖极薄层纤维组织,种植体表面机械铣削条痕尚没有被粘附组织所覆盖;而表面粗化及颈部双头微螺纹组种植体表面的粘附组织较均匀,几乎完全覆盖种植体表面的粗化多孔结构,可见少量骨组织。3.2术后8周颈部双头微螺纹组种植体表面覆盖薄层纤维及少许骨组织,种植体表面机械铣削条痕尚没有完全被粘附组织所覆盖;而表面粗化及颈部双头微螺纹组种植体表面的粘附组织较厚,骨组织粘附于种植体表面的粗化多孔结构。3.3术后12周颈部双头微螺纹组种植体表面覆盖薄层骨组织,种植体表面机械铣削条痕几乎完全被粘附骨组织所覆盖,而表面粗化及颈部双头微螺纹组种植体表面的粘附骨组织厚,呈蜂窝状,完全覆盖种植体表面的粗化多孔结构。4 EDX分析4周时颈部双头微螺纹组种植体表面粘附组织中钙26.45%、磷21.29%,而在表面粗化及颈部双头微螺纹组种植体钙52.26%、磷32.99%;8周时颈部双头微螺纹组种植体表面粘附组织中钙37.72%、磷25.63%,而在表面粗化及颈部双头微螺纹组种植体钙53.97%、磷34.39%;12周时颈部双头微螺纹组种植体表面粘附组织中钙48.06%、磷32.05%,而在表面粗化及颈部双头微螺纹组种植体钙54.23%、磷34.56%。5组织学观察术后12周时,颈部双头微螺纹组、表面粗化及颈部双头微螺纹组种植体周围可见清晰的板层状骨,颈部双头微螺纹组结合骨板较薄、致密性稍低,较为连续;表面粗化及颈部双头微螺纹组结合骨板较厚、致密,连续性好,且周围新骨内可见较多的骨细胞。结论:1柱状V形螺纹种植体不同颈部形态对种植体-骨界面应力值、应力分布有影响,整体应力集中区域均位于种植体的颈部皮质骨区及根尖部。2同一螺纹形态颈部单头微螺纹组能够明显降低轴向、水平向及斜向加载时的皮质骨区的Von-Mises等效应力、最大主应力。3宽颈组与颈部单头微螺纹组相比,在轴向、水平向及斜向加载时的皮质骨区的Von-Mises等效应力、最大主应力值较高。4均衡螺纹组与宽颈组相比,在轴向、水平向及斜向加载时的皮质骨区的Von-Mises等效应力、最大主应力值较高。5同一螺纹形态颈部双头微螺纹组在轴向、水平向及斜向加载时的皮质骨区的Von-Mises等效应力、最大主应力值较高。6宽颈组、颈部单头微螺纹组、颈部双头微螺纹组种植体疲劳耐受性能相似,均高于均衡螺纹组。7钛颗粒喷砂后HCL/H2SO4热酸蚀表面种植体较机械加工表面种植体的疲劳耐受性能有所降低,但能够满足临床功能状态下的力学要求。8各观察时间点,表面粗化及颈部双头微螺纹组的旋出扭矩值均较颈部双头微螺纹组高;颈部单头微螺纹组与颈部双头微螺纹组旋出扭矩值无明显差别,均高于均衡螺纹组和宽颈组,宽颈组最低。各组扭矩值变化趋势大体一致,植入后8周时较4周有所升高,12周时升高明显达到峰值。9各观察时间点,钛颗粒喷砂后HCL/H2SO4热酸蚀表面种植体表面沉积的骨反应物及其中的钙、磷含量均较机械加工表面种植体多,且形成时间较早。10植入术后12周时,钛颗粒喷砂后HCL/H2SO4热酸蚀表面种植体结合骨板宽度、致密性、连续性均较机械加工表面种植体好。
[Abstract]:The first part of the unbalanced threaded titanium dental implant three dimensional finite element stress analysis objective: to play a very important role in implant biomechanical optimization of thread form design, it can increase the contact area of the bone implant, improve the initial implant stability, improve the stress distribution of bone interface. The bone implant thread with single thread balanced distribution, and in the cortical area of the section of micro screw, bone length and depth of the smaller cancellous zone by pitch thread is relatively wide, literatures have confirmed that this imbalance has good effect on mechanical thread design, but is rarely reported in biomechanics the characteristics of different micro neck threads. The correct design of the shape of the implant can make the stress on the interface between implant and bone as far as possible, especially reduce the stress concentration at the upper edge of the cortical bone. It will help reduce bone resorption, reduce the possibility of loosening of implant and prolong its service life. In order to improve the long-term success rate of implant restoration, it is necessary to optimize the design of implant thread, especially the optimization of neck micro thread structure and the optimal combination of threads. The purpose of this study was to investigate the biomechanical properties of different cervical threaded designs. Methods: 1 implant groups were divided into four different neck shapes into balanced thread group, wide neck group, neck single head micro screw group, and neck double head micro thread group. 2 the model 2.1 of the mandible was modeled according to the CT scan of the head, and a new project was established in the Mimics 16. Based on CT image gray value will be part of the extract of bone, bone masks for editing, get accurate only includes void pixel mask model of mandible, automatic calculation of 3D model by pixel mask, will eventually produce the initial mandible three-dimensional geometric model with STL (Standard Template Library) format. 2.2 optimization model STL format will be a preliminary mandible three-dimensional model into Geomagic studio 2013, using several fast smoothing initial model smoothing, improve the polygonal surface performance, obtained the mandible polygon model, to obtain accurate surface phase, surface patch model of mandible. After the CAD object conversion, the CAD model of the mandible was finally obtained. 2.3, generate cortical bone and cancellous bone in the Geomagic polygon stage, and get the polygonal model of the interface between the cortical bone and cancellous bone in the mandibular bone in the Geomagic polygon stage by extracting and removing the cross faces. Then, according to the above steps, we gradually get the CAD model of the cancellous bone with the external interface as the interface. The acquired CAD model of the mandible and the CAD model of the cancellous bone were introduced into Solidworks 2015, and the cortical bone model was obtained by Boolean operation. 2.4 implant and mandible assembly, four groups of implant were placed in the same place in the first molar area of mandible, and Solidworks was set up on the top of the implant to build a 3.2mm abutment. On the top, a porcelain restoration with a thickness of 2mm was built. Import it into the Ansys Workbench 14.5 in sat format. 2.5 mesh generation is based on hexahedron and tetrahedron as an auxiliary mesh. The cell size is about 0.5mm, and it is properly encrypted for implants and adjacent nodes and units. The properties and constraints of 2.6 materials are assumed to be homogeneous isotropic linear elastic materials, and the material is deformed into small elastic deformation. The degree of freedom of all the nodes at the top of the condyle on both sides of the mandible was rigidly constrained, and the implant and bone tissue were combined with 100% bones. 2.7 loading conditions were applied to the following three load conditions: the axial load was 100N, the lateral buccal side was 50N, and the axis of the implant was 30 degrees, from the buccal side to the tongue side to the 100N. 2.8 evaluation index analysis Von-Mises equivalent stress and maximum principal stress. Results: 1, the total stress distribution characteristics of implant bone interface had different effects on implant bone interface stress value and stress distribution. The whole stress concentration area was located in the neck of implant and root tip of implant. 2 axial loading of 100 Newton for balanced thread group, wide neck group, single head neck micro thread group, double neck micro thread group, cortical bone area, the maximum equivalent stress are respectively 46.58MPa, 35.25MPa, 20.98MPa, 58.01MPa, loose bone area equivalent maximum stress value is 3.64MPa, 7.45MPa, 2.60MPa, 12.38MPa respectively. For the four groups of implants, the maximum principal in the cortical bone at the upper edge of the stress values were 0.97MPa, 0.89MPa, 0.79MPa, 1.22MPa; the maximum principal cortical and cancellous bone at the junction of the stress values were 1.72MPa, 3.89MPa, 0.45MPa, 8.07MPa; the maximum principal in at the end of the implant. The stress values were 0.73MPa, 0.67MPa, 0.64MPa, 0.57MPa; four groups of implants in the cancellous bone region of the maximum principal stress value loci showed low level. 3 buccolingual horizontal loading 50 Newton for balanced thread group, wide neck group, single head neck micro thread group, double neck micro thread group, cortical bone area, the maximum equivalent stress are respectively 53.21MPa, 41.93MPa, 36.95MPa, 64.18MPa, loose bone equivalent stress, the maximum value is 3.72MPa, 6.57MPa 3.77MPa and 4.07MPa respectively. For the four groups of implants, the maximum principal in the cortical bone at the upper edge of the stress values were 41.77MPa, 39.61MPa, 29.67MPa, 46.99MPa; the maximum principal cortical and cancellous bone at the junction of the stress values were 9.45MPa, 2.80MPa, 1.73MPa, 9.49MPa; the maximum principal in at the end of the implant. The stress values were 0.07MPa, 0.09MPa, 0.15MPa, 0.26MPa; maximum four groups of implant in cortical bone area, the stress values showed a higher level. 4 when oblique loading is 100 Newton, for the balanced screw group, wide neck group, neck single head micro thread group and neck double head micro thread group, the maximum equivalent stress of cortical bone area is 49.37MPa and 47.78MP respectively.
【学位授予单位】：河北医科大学
【学位级别】：博士
【学位授予年份】：2017
【分类号】：R783.6

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