种植体穿通下颌骨对骨界面应力分布的影响

目的：为了探讨下颌种植牙穿通下颌骨后对骨界面应力分布的影响。方法：采用三维有限元方法,通过单个穿下颌螺旋型种植体的种植,了解穿下颌种植后对骨界面应力分布的影响。结果：穿下颌种植减小了颈周密质骨内的应力,加大了根端侧穿下颌骨下缘处的应力,减小了骨界面的位移。结论：穿下颌种植,改变了骨界面的最大应力分布部位,使最大应力位于根端侧下颌骨下缘处。     

全下颌牙种植固定义齿及支持骨应力的三维有限元分析——种植体植入不同深度应力的比较

本研究应用CT扫描法借助ANSYS软件建立了全下凳牙种植固定义齿的三维有限元模型．比较了双颏孔间区螺旋柱状种植体植入深至下颌骨下缘皮质骨及未深至下颌下缘两种不同情况下全下颌种植固定义齿受载时应力分布规律。结果表明：种植体底部是否深至下颌下缘皮质骨，对种植体一支架应力的影响不大，而对周围骨的应力影响较大，在双颏孔间区将种植体深至下颌下缘皮质骨，更有利于应力均匀分布。     

上颌前磨牙区种植单端桥及骨组织的三维有限元分析

目的 分析上颌前磨牙区种植单端桥基牙及其周围支持骨组织在静态加载方式下的应力分布状况。方法 采用三维有限元分析方法，研究分别在分散垂直和斜向加载条件下，单端固定桥中基牙种植体及其周围骨组织的应力分布情况。结果 上颌前磨牙区两类骨质中种植单端桥在不同加载方式下，种植体-基台复合体所受应力均集中于对应颈部皮质骨部位的种植体远中部位；周围骨组织中皮质骨应力高于松质骨，均以颈部皮质骨远中部位最大，各向加载时D3模型皮质骨的最大应力值均小于D4模型；与垂直加载比较，颊舌向加载时两类模型最大位移均增大，各向加载时D3模型的种植体-基台复合体最大位移均小于D4模型。结论 从生物力学角度分析上颌前磨牙区种植单端桥的设计具有合理性；高密度松质骨（D3）更有利于上颌前磨牙区种植单端桥的应力分布。     

全下颌牙种植义齿及支持组织应力的三维有限元分析：Ⅱ.固 …

采用三维有限元法考究全下颌种植固定义在正中Ｈｅ均布加载，集中加载，前伸Ｈｅ加载下，其种植体－支架，人工牙，皮质骨，松质骨的应力分布变化规律，结果显示：（１）三种加载方式的种植体颈部及周转骨界面应力增高，以叶状种植体最明显，但种植体－支架，支持骨应力分布趋于均匀，分布规律近似，提示临床设计具有力学可行行；（２）全下颌牙种植固定义齿由刚性较好的支架有效地分散载荷。     

全下颌牙种植义齿及支持组织应力的三维有限元分析──Ⅱ． 固定式种植义齿在三种加载方式下应力分析比较

采用三维有限元法考察全下颌种植固定义齿在正中均布加载、集中加载，前伸加载下，其种植体－支架、人工牙、皮质骨、松质骨的应力分布变化规律。结果显示：①三种加载方式的种植体颈部及周围骨界面应力增高，以叶状种植体最明显，但种植体－支架、支持骨应力分布趋于均匀，分布规律近似，提示临床设计具有力学可行性；②全下颌牙种值固定义齿由刚性较好的支架能有效地分散载荷。     

下颌4枚与6枚种植体全口固定义齿的有限元分析

目的：采用有限元分析法,比较4枚和6枚种植体支持下颌固定全口义齿的骨及种植体应力分布特点,为临床种植修复提供生物力学参考依据。方法：建立4枚种植体6mm悬臂和6枚种植体6mm悬臂的2组下颌种植支持式固定全口义齿的三维有限元模型,在悬臂末端垂直加载100N,应用Ansys软件进行分析处理,得到2组设计的种植体,测定最大压应力和最大拉应力。结果：2组设计的骨应力都集中在离受载区最近的2枚种植体颈部骨皮质区。6个种植体组骨应力较小,种植体应力集中在末端和中间种植体的颈部,修复支架应力集中在与远中末端种植体相连接处。2组的种植体应力和种植上部结构应力相近。结论：末端种植体骨应力集中,易发生松动失败;种植体颈部应力集中,易发生植入体与基桩连接失败。2组设计都符合生物力学分布原理。但4种植体设计骨应力较高,适用于前牙区骨质量较好的病例。     

三种下颌种植固定全口义齿的初步应力比较

目的:比较同一病例3组下颌种植固定全口义齿的骨及种植体应力分布特点,为临床种植修复提供生物力学分析依据.方法:建立4个种植体3mm悬臂,6个种植体3mm悬臂,8个种植体3mm悬臂3组下颌种植固定全口义齿的三维有限元模型.在悬臂末端垂直加载100N.结果:种植全口义齿悬臂末端垂直加载时,各组种植体周围颈部骨应力集中.6个种植体组骨压应力和拉应力都最小.种植体应力主要集中在末端和中间种植体的颈部.种植修复上部支架应力主要集中在与远中末端种植体相连接处.结论:末端种植体骨应力集中,易发生松动失败;种植体颈部应力集中,易发生植入体与基桩连接失败.6个种植体支持组修复设计在该病例中较符合生物力学分布原理.     

下颌改良杆卡式种植覆盖义齿的应力分布——垂直载荷与斜向载荷的比较

采用三维各向异性有限元法分析全下颌改良杆卡式种植覆盖义齿垂直载荷与斜向载荷下的应力分面。结果显示,种植体的最大应力出现在种植体骨外段的近、远中面;种植体界面骨组织的最大应力位于种植体颈部周围的骨皮质界面;斜向载荷下种植体及其骨组织界面的应力值高于垂直载荷时,且垂直载荷下种植体骨界面的应力分布更均匀;近远中向斜向加载时种植体及其骨组织界面的最大应力值高于舌颊向加载时。     

牙种植体即刻负载骨界面应力分布的三维有限元分析

目的：用三维有限元法分析牙种植体即刻负载骨界面的力学特性。方法：采用CT扫描和自主开发的USIS软件建立螺纹种植体即刻负载的三维有限元下颌骨模型，用ANSYS计算垂直加载、颊舌向450及近远中向45°加载150N力时种植体骨界面的Yon Mises应力、应变值。结果：垂直加载时骨界面的Yon Mises应力集中于颈部舌侧骨皮质，应变分布均匀，以颈部骨皮质、底部颊侧骨松质及颊侧螺纹接触部位的松质骨较为集中：颊舌向加载时骨界面的Yon Mises应力也集中于颈部舌侧骨皮质，但最大值是垂直加载时的4．15倍，应变分布不均匀，主要集中于颈部舌侧骨皮质，最大值是垂直加载时的3．98倍；近远中斜向加载时骨界面的Yon Mises应力集中于颈部远中侧骨皮质，最大值是垂直加载时的3．72倍，应变集中于底部近中侧骨松质，最大值是垂直加载时的1．51倍。结论：即刻垂直加载时，种植体周围骨质应力及应变无明显集中，分布较均匀，颊舌向及近远中向加载时应力、应变明显增大，分布不均匀。     

牙种植生物力学分析的CAE前处理方法研究

目的：本文考察牙种植有限元分析中下颌骨模型几种前处理方法下的应力分布情况和特点。方法：采用螺旋CT扫描、mimics软件等建立下颌骨三维有限元模型,在有限元软件中模拟咬合力加载,分析种植体对于下颌骨应力分布情况。结果：三种不同处理情况下的下颌骨应力分布有较大的共同点,应力都主要集中在皮质骨部分,在松质骨部分三种模型应力值显著低于皮质骨部分。结论：可根据不同应用选择下颌骨模型前处理方法,在不影响考察松质骨应力分布的条件下,模型前处理可作适当简化。     

Implant–Bone Interface Stress Distribution in Immediately Loaded Implants of Different Diameters: A Three-Dimensional Finite Element Analysis

Purpose: To establish a 3D finite element model of a mandible with dental implants for immediate loading and to analyze stress distribution in bone around implants of different diameters. Materials and Methods: Three mandible models, embedded with thread implants (ITI, Straumann, Switzerland) with diameters of 3.3, 4.1, and 4.8 mm, respectively, were developed using CT scanning and self‐developed Universal Surgical Integration System software. The von Mises stress and strain of the implant–bone interface were calculated with the ANSYS software when implants were loaded with 150 N vertical or buccolingual forces. Results: When the implants were loaded with vertical force, the von Mises stress concentrated on the mesial and distal surfaces of cortical bone around the neck of implants, with peak values of 25.0, 17.6 and 11.6 MPa for 3.3, 4.1, and 4.8 mm diameters, respectively, while the maximum strains (5854, 4903, 4344 μ?) were located on the buccal cancellous bone around the implant bottom and threads of implants. The stress and strain were significantly lower (p < 0.05) with the increased diameter of implant. When the implants were loaded with buccolingual force, the peak von Mises stress values occurred on the buccal surface of cortical bone around the implant neck, with values of 131.1, 78.7, and 68.1 MPa for 3.3, 4.1, and 4.8 mm diameters, respectively, while the maximum strains occurred on the buccal surface of cancellous bone adjacent to the implant neck, with peak values of 14,218, 12,706, and 11,504 μm, respectively. The stress of the 4.1‐mm diameter implants was significantly lower (p < 0.05) than those of 3.3‐mm diameter implants, but not statistically different from that of the 4.8 mm implant. Conclusions: With an increase of implant diameter, stress and strain on the implant–bone interfaces significantly decreased, especially when the diameter increased from 3.3 to 4.1 mm. It appears that dental implants of 10 mm in length for immediate loading should be at least 4.1 mm in diameter, and uniaxial loading to dental implants should be avoided or minimized.     

Three-dimensional finite element analyses of four designs of a high-strength silicon nitride implant

The effects of implant shape and size on the stress distribution around high-strength silicon nitride implants under vertical and oblique forces were determined using a three-dimensional finite element analysis. Finite element models were designed using as a basis the serial sections of the mandible. Using Auto-CAD software, the model simulated the placement of implants in the molar region of the left mandible. Results of the analyses demonstrated that mainly the implant root shape and the directions of bite forces influence the stress distributions in the supporting bone around each implant. Implant size is a lesser factor. The serrated implants presented a larger surface area to the bone than either the cylindrical or tapered implants, which resulted in lower compressive stress around the serrated implants. With increasing implant diameter and length, compressive stress decreased. The mean compressive stress distribution on the serrated implants was more flat (platykurtic) than on either the cylindrical or tapered implants. Results of studies on two load directions (vertical and oblique) showed that, in either case, the compressive stress in the cortical bone around the neck of the implant was higher than in the cancellous bone along the length of the implant. The most extreme principal compressive stress was found with oblique force. This study provides the first information on the relationship between shape of the silicon nitride implant and stress on the supporting bone.     

种植牙根端接触骨质类型对骨界面应力分布影响的三维有限元分析

目的为了探讨种植牙根端接触骨质类型对种植牙周骨界面应力分布的影响方法应用三维有限元方法对螺旋型种植牙周骨界面应力分布进行了分析结果种植牙根端与密质骨或与松质骨接触时在骨界面应力分布上有较大的差异种植牙根端与松质骨接触时最大压应力位于颈周而与密质骨接触时则位于根端骨内结论种植牙根端与密质骨接触可降低种植牙颈周骨内应力减小骨界面的位移运动但增加了根端骨内的应力从减小颈周骨内应力的角度出发种植牙根端与密质骨接触也是一种良好有效的手段     

种植体颈部微螺纹结构对种植稳定性影响的三维有限元分析

目的：通过分析种植体颈部螺纹结构,以及Von-Mises应力和应变分布情况,为种植体结构设计提供生物力学实验数据和理论参考依据。方法：本文通过运用三维计算机辅助设计CAD软件,设计建立颈部有螺纹和无螺纹三维种植体模型,利用CT扫描数据重建下颌骨三维模型,牙齿咬合面与上颌骨长轴面形成的倾角为45。,沿此方向施加120N的力作用在牙冠顶部,以模拟实际咬合状态受力。利用有限元分析软件模拟即刻负荷（即骨一种植体之间摩擦系数0．3）和骨愈合后期（即骨一种植体之间为绑定接触）两种加载情况下种植体与周围骨组织之间Von-Mises应力和应变峰值大小及分布状况进行比较和分析。结果：在即刻负荷的条件下,Von-Mises应力、应变在颈部光滑的种植体与皮质骨之间分布均匀,峰值分别为28．654MPa、0．01334mm;而颈部有螺纹种植体与皮质骨之间的Von-Mises应力、应变峰值分别为52．630MPa、0．015864mm。在骨愈合后期,颈部光滑的种植体,在相同咬合力作用下,皮质骨Von-Mises应力、应变峰值分别为36．975MPa、0．010272mm;而具有颈部螺纹设计的种植体所引起的Von-Mises应力、应变峰值分别为35．857MPa、0．010234mm。在骨愈合后期,增加种植体颈部的螺纹设计使得皮质骨所受Von-Mises应力减小1．118MPa、应变峰值也有减小的趋势。结论：即刻负载种植时,增加种植体颈部螺纹结构,在种植体一骨愈合后期,颈部的微螺纹结构可使种植体一骨接触界面的Von-Mises应力和应变峰值有所减小,并且有效改善了接触界面的应力分布状况,有助于其长期稳定性及种植成功率的提高。     

Loading conditions of endosseous implants in an edentulous human mandible: a three-dimensional, finite-element study

The design of dental superstructures influences the loading on dental implants and the deformation of the anterior interforaminal bone in an edentulous mandible. This deformation causes stress in the bone around the implants and may lead to bone resorption and loss of the implant. The stress distribution around dental implants in an edentulous mandible was calculated by means of a three-dimensional, finite-element model of the anterior part of the jaw. This model was built from data obtained from slices of a single human mandible and was provided with four endosseous implants in the interforaminal region. The implants were either connected with a bar or remained solitary. The solitary implants or the bars were loaded either uniformly or non-uniformly. In case of a non-uniform distribution, either the central bar or the central implants were loaded or the lateral bars or the lateral implants were loaded. The most extreme stresses in the bone were always located around the neck of the implant. In the case of the uniform distribution of the loading there were more or less equal extreme principal stresses around the central and lateral implants. If the load was not uniformly distributed on the superstructure then the implant that was nearest to the place of loading showed the highest stress concentration; with connected implants there was a reduction in the magnitude of the extreme principal stresses compared to solitary implants.     

种植牙即刻负载与延期负载的生物力学三维有限元分析

目的比较即刻负载和延期负载对种植体骨界面生物力学分布的影响。方法采用CT扫描和自主开发的USIS软件建模,用有限元法计算分析即刻负载和延期负载时种植体骨界面的应力、应变及种植体的位移。结果即刻负载时种植体骨界面的VonMises应力稍小于延期负载,均集中于种植体颈部骨皮质,底部骨松质次之;但VonMises应变有较明显的增加,均集中于种植体底部骨松质和螺纹部位;种植体的位移较延期负载略有增大。即刻负载种植体和延期负载种植体在受到颊舌向力时,VonMises应力、应变及位移均有不同程度的增加。结论即刻负载时种植体骨界面的生物力学分布规律与延期负载时相似,受到侧向力时应力、应变增大。种植牙即刻负载技术是可行的。     

无牙下颌固定种植义齿带末端悬臂的应力分析

目的:比较不同悬臂设计下颌种植支持全口义齿的骨及种植体应力分布特点,为临床种植修复提供生物力学分析依据。方法:建立3组下颌6个种植支持全口义齿的三维有限元模型,悬臂分别为3、6、9 mm。在悬臂末端垂直加载100 N的力。结果:种植全口义齿悬臂末端垂直加载时,末端种植体骨应力集中,易发生松动失败;末端种植体及中间种植体颈部应力集中,易发生植入体与基桩连接失败;连梁应力集中在与末端种植体连接处,此处易发生折断。悬臂长度增加骨应力、种植体应力及连梁应力明显增加。结论:悬臂越短越有利于力的均匀分布。6个种植体支持短悬臂修复设计较符合生物力学分布原理。     

不同骨结合率对种植体骨界面应力分布的影响

目的:通过建立含牙种植体的无牙下颌骨三维有限元模型,分析不同的骨结合率对种植体骨界面应力分布的影响。为临床设计种植义齿治疗方案提供理论依据。方法:使用螺旋CT扫描、CAD技术、有限元软件等,建立含牙种植体的下颌骨三维有限元模型;分析不同的骨结合率对种植体骨界面应力分布的影响。结果:不同骨结合率都会出现种植体颈部皮质骨的应力集中;当骨结合率大于或等于60%时,颈部皮质骨处应力值明显下降。结论:随着骨结合率的增加,颈部皮质骨的应力值有下降的趋势;提示临床医生在进行种植义齿修复时,需考虑提高种植体骨结合率,避免影响骨结合的不利因素,从而提高种植的成功率。