下颌骨髁突支架的个体化设计与初步构建

Objective To explore the method of designing and manufacturing the mandibular condyle scaffold individually by rapid prototyping technologies and reverse engineering.Methods Cranial CT image data were processed in Mimics software for reconstruction of one side of ramus of mandible, and were inputted into Solidworks software to edit by the format of stl. A negative mold of the mandibular condyle scaffold was obtained. The mold was fabricated by resin materials utilizing rapid prototyping. Biomaterials were filled into the resin mold. When the materials were cured, we eliminated the resin mold and acquired a multi-pores three dimensional mandibular condyle scaffold model. The general morphology and microstructure of the scaffold model were observed by scanning electron microscopy (SEM). Results The mandibular condyle scaffold made of biomaterials was accordance with the one our computer designed. SEM observation revealed that the model was made of collagen in the cartilage-like layer and calcium phosphate cement/poly (lactic- co-glycolic acid) in the bone-like layer. Conclusion It is feasible to fabricate mandibular condyle scaffold individually by using reverse engineering and rapid prototyping technology.     

永生化下颌骨髁突软骨细胞的微囊化研究

为了探讨微囊包裹软骨细胞在软骨组织工程中的适用性 ,根据气流切割原理采用海藻酸钠 -多聚赖氨酸 -海藻酸钠 ( APA)对永生化下颌骨髁突软骨细胞 ( Im mortalized mandibular condylar chondrocyte,IMCC)进行微囊包裹。用倒置显微镜观察、台盼蓝染色、细胞记数、HE染色、免疫组化等方法检测微囊的大小、细胞的生长及微囊内组织的软骨特性等情况。研究发现 ,IMCC可在微囊内存活 ,活细胞率 >80 % ,微囊直径平均 779μm。细胞数量随着培养时间的延长逐渐增多 ,约 2 0 d左右达到平台期 ,细胞在囊内呈簇样生长 ,高表达软骨特异的蛋白多糖和 型胶原。提示 IMCC可在微囊内形成类软骨组织样结构 ,微囊技术适用于包裹软骨细胞     

下颌骨髁突解剖参数的相关性分析及临床意义

目的通过测量下颌骨髁突的解剖学参数,为国人下颌骨髁突假体设计提供参数。方法用国产游标卡尺测量正常成年人下颌骨髁突的相关参数共8项指标。结果左右侧下颌骨髁突各项解剖参数相比,差异均无显著性意义(P>0.05)。内侧最凸点与外侧最凸点距离,前缘测量点与后缘测量点直线距离,关节面最高点与下颌骨髁突内侧缘明显缩窄处垂直距离,下颌骨髁突关节面最高点与外侧最凸点直线距离与左右下颌角外侧最凸点间距离,均成正相关关系。结论通过测量左右下颌角外侧最凸点间距离的数值可推算出国人下颌骨髁突假体个性化设计所需的参数。     

咀嚼肌牵动的下颌骨三维有限元建模与数值分析

目的：应用有限元方法分析咀嚼肌牵动的下颌骨应力状态。方法：采用数字中国人下颌骨CT图像三维重建，生成有限元模型，通过解剖学研究和测量，确立颞肌、咬肌、翼内肌、翼外肌的附着部位面积和肌力线方向。结果：建立了咀嚼肌牵动的下颌骨生物力学分析模式，有限元计算得到下颌骨应力分布状态，Von Mises应力主要集中于髁突，冠突，咀嚼肌附着部位和磨牙区，当右侧第1磨牙与第2磨牙咀嚼模拟时应力峰值为20．61MPa．当第1前磨牙与第2前磨牙咀嚼模拟时应力峰值达到了22．09MPa。结论：有限元分析技术，结合下颌骨血管神经走向及He力与咀嚼功能测定等，为下颌骨截骨术和骨牵张术提供了一种术前设计的定量方法。     

包含颞下颌关节的下颌骨有限元建模

为获得颞下颌关节下颌骨的应力分布提供更为有效的有限元模型。用Mimics10．0导入正常人的颌面CT建立其下颌各部位的有限元模型,通过CAE软件ABAQUS 6．10进行有限元分析。获得了完整的下颌骨、颞下颌关节有限元模型,及后牙咬合状态下模型各部位应力分布等数据。通过分析数据发现,关节盘高应力区主要集中在关节盘中带和后带,而关节盘各部分应力表现为关节盘颊侧应力高于舌侧,顶部应力高于底部,中带平均应力最大,后带次之,前带最小。     

不同训练方案对下颌骨单侧髁突骨折患者术后开口度训练效果的影响

目的观察不同训练方案对下颌骨单侧髁突骨折患者术后开口度训练效果的影响。方法选取我院收治的80例行手术治疗的下颌骨单侧髁突骨折患者,依据术后训练方案分为对照组(n=36)与干预组(n=44),对照组给予常规康复训练,干预组给予下颌运动康复训练,比较2组患者术前、术后1个月、术后6个月下颌主动张口度、健侧活动度、患侧活动度及前后活动度,观察2组患者术后6个月张口受限、咬合关系紊乱情况。结果干预组术后1个月与术后6个月下颌主动张口度、下颌健侧活动度、下颌前后活动度大于对照组,差异有统计学意义(P<0.05);术后6个月时,干预组张口受限率与咬合关系紊乱率低于对照组,差异有统计学意义(P<0.05)。结论相较于常规康复训练,下颌运动康复训练方案对下颌骨单侧髁突骨折患者手术后开口度与活动度的训练效果更好,可缩短下颌运动功能恢复进程,减少张口受限及咬合关系紊乱。     

骨折愈合进程下髁突囊内骨折内固定的有限元分析

为重建由于髁突囊内骨折引起的颞下颌关节结构的不连续,需选择合适的内固定方式,采用有限元方法将B型髁突骨折的四种固定方式置于骨折愈合进程中进行模拟,以获得最适宜的长效内固定方式。基于CT图像构建了下颌骨模型,在右侧髁突模拟骨折裂隙与微型钛板,加载边界条件获取有限元结果并分析受力、位移。考察术后当天及4、8、12周骨折愈合进程中4种固定方式即：一个直板、两个平行直板、一个直板+一个L板以及两个L板的力学行为,得出两平行平板的力学特性最好（采用最大等效应力比较,两平行平板的最大应力术后稳定在443 MPa,且其上应力变化平稳）,一个直板+一个L板的稳定性最好（采用固定端与游离端的位移和转角作为度量标准,其最大相对位移0.045 mm,最大相对转角基本稳定在0.0378 度,为系统提供可靠的稳定性。临床可根据适应症选择双板固定治疗髁突囊内骨折,不建议采用单板固定,且双板固定考虑两平行直板或一个直板+一个L板。     

下颌骨角部受力时应力分布的三维有限元分析

背景：关于下颌骨撞击后,下颌骨不同部位的骨折危险性的相关研究比较薄弱。 目的：应用有限元方法分析下颌骨角部受瞬间外力作用下应力分布的情况和特点。 方法：采用薄层CT扫描技术、医学影像三维重建软件Amira联合Unigraphics NX造型软件建立下颌骨三维模型。在Ansys软件中,于左侧下颌角区分别施以与矢状面垂直,平行的两个不同方向的1 000 N压力,获取受力后下颌骨应力分布状况和薄弱区域受力大小。 结果与结论：建立了下颌骨有限元模型,当左侧下颌角受到水平向右垂直于矢状面的外力时,左右两侧的下颌角及髁状突颈部极易造成骨折,正中联合区域内侧面,左侧颏孔区可能会出现骨裂,而右侧颏孔区仅会造成轻微损伤。当左侧下颌角下缘受到垂直向上平行于矢状面的外力时,左右两侧的下颌角及髁状突颈部极易造成骨折,正中联合区域内侧面和左侧颏孔区可能会出现骨裂,而右侧颏孔区仅会轻微损伤。提示当下颌骨角部受到瞬间外力时,应力主要集中在下颌骨的薄弱区域,应力较大部位与骨折易发部位密切相关。且在薄弱区域中,两侧下颌角及髁状突颈部的损害最为严重。     

下颌骨缺损腓骨瓣修复不同固定方式的有限元分析

背景:肿瘤、外伤等原因常常造成下颌骨节段性缺损,血管化腓骨瓣同期重建下颌骨缺损是目前最主要的修复方式。目前在临床上既有用重建钛板进行固定,又有用小型钛板固定,有临床回顾性研究表明重建钛板和小型钛板固定方式患者术后并发症率无明显差异,但目前仍缺少固定稳定性相关的生物力学研究。目的:试验用三维有限元法分析下颌骨节段性缺损腓骨瓣修复时用重建钛板和小型钛板固定后的应力分布和稳定性。方法:选择1例牙列完整的成年男性进行CT扫描,并将数据录入计算机之后重建下颌骨及牙列模型,根据下颌骨缺损的Jewer分类,建立H(一侧下颌体、下颌角、下颌升支和髁突的缺失),L(一侧下颌体缺失)和C(双侧下颌骨颏部缺失)3类缺损三维模型,利用三维有限元分析法,对这3种下颌骨缺损腓骨修复后重建板和小型板固定的力学分布特点和稳定性进行对比研究。结果与结论:①从应力云图可以大致判断,正常下颌骨应力较大值主要发生在髁突、髁颈、下颌角、磨牙、钛板钛钉等周围区域处,尤其以下颌角附近处应力最大;②H类缺损在重建钛板修复下颌骨时将对下颌角附近产生较大应力,局部应力集中达185MPa,在H类小型钛板、L类小型钛板及重建钛板修复条件下,钛板的应力为117-135 MPa,腓骨块的应力最大值基本在30.4 MPa以下,钛钉应力最大值为56.2 MPa;③H及L类缺损小型钛板、重建钛板修复后骨断端相对位移变化为15-18μm,C类缺损下颌骨钛板修复后骨断端基本不产生相对位移;④结果证实,重建钛板和小型钛板均能满足这3种缺损腓骨修复的生物力学要求。     

种植体联合牙半切剩余牙体共同支持下颌磨牙的三维有限元分析

BACKGROUND: Tooth hemisection contributes to preserving partial tooth structure and periodontal ligament that are able to reduce the resorption of alveolar bone. However, the traditional fixed partial denture (FPD) for dental restoration after hemisection jeopardizes the health of abutment tooth. Given this, the use of dental implant offers a new option for tooth restoration. OBJECTIVE: To analyze the feasibility of preserving a mandibular molar after hemisection by combining an inserted dental implant with the residual tooth by means of finite element analysis. METHODS: Based on the image data of a volunteer, three models with different ways of restorations were created: the model of combining implant and residual tooth after hemisection to support a molar crown (combined model), the model of implant to support a molar crown (implant model) and the model of FPD. Densities of two kinds of spongy bones were assigned respectively. Vertical load of 100 N was applied on the prosthesis. Biomechanical properties of different models were analyzed. RESULTS AND CONCLUSION: (1) Displacement of the tooth and implant: As the decrease of the density of spongy bone, displacements of the tooth and implant increased in the combined model. The implant displacement was higher in the combined model as compared with the implant model. For the combined model, the implant displacement was lower than that of the residual tooth. (2) Stress in the cortical bone: Stress in the cortical bone in models with low-density spongy bone was higher than that in the corresponding models with high-density spongy bone. Under the condition of high-density spongy bone, the highest values were obtained in the implant model, followed by the combined model and FPD model. Under the condition of low-density spongy bone, the highest values were obtained in the combined model, followed by the implant model and FPD model. (3) Strain in the spongy bone: Strain in the spongy bone in models with low-density spongy bone was higher than that in the corresponding models with high-density spongy bone. Under the condition of high-density spongy bone, the highest values were obtained in the FPD model, followed by the combined model and implant model. Under the condition of low-density spongy bone, the highest values were obtained in the combined model, followed by the FPD model and implant model. From the biomechanical point of view, it can be concluded that the combined use of an implant and residual molar after tooth hemisection is an acceptable treatment option under the condition of high-density spongy bone.     

有限元法分析胸腰椎骨折椎弓根钉置入内固定的应力分布

BACKGROUND: Spinal surgery requires a relatively high accuracy. At present, the study of pedicle screw fixation is more focused on the safety and stability, but the premise is the safe and effective screw placement. Selection of the insertion point is the key to success.     

钛板重建下颌骨体部缺损的生物力学变化

BACKGROUND:Three-dimensional finite element has been widely used in the oral cavity field, but little is reported on the three-dimensional finite element reconstruction of the mandibular body using titanium plate. OBJECTIVE:To study the biomechanical characteristics of reconstructing the mandibular body using titanium plate. METHODS:We established a three-dimensional finite element model of mandibular body defect undergoing reconstruction using bicortical titanium screws and titanium plate. Under the simulated normal occlusion state, a 200 N vertical load was added to the central fossa of the occlusal surface of the right mandible first molar. Then, stress distribution and maximum displacement of the mandible, titanium screw, and titanium plate were analyzed. RESULTS AND CONCLUSION:Under the simulated normal occlusion state, mandible stress was concentrated in the mandibular body and mandibular branch, especially in the anterior and posterior edges of the mandibular branch and the lower edge of the mandible. The stress in the posterior edge of the mandible was lower than that in the anterior edge of the mandible, and moreover, the contact site between the titanium plate and the mandible also presented a concentration of stress. The maximum stress of the bicortical titanium screws appeared near the screw cap, and the stress was also concentrated at the contact site between the titanium screw and the titanium plate. The maximum stress of the titanium screw at the ascending branch of the mandible was higher than that of the titanium screw at the anterior end of the defect. For the titanium plate, the stress was mainly concentrated at the fixed site of the titanium screws; the peak stress of the anterior and posterior edges of the titanium plate was found at the contact site between the anterior end of mandibular defect and the titanium stress as well as between the ascending branch of the mandible and the titanium screw. After mandibular body reconstruction using the titanium plate, a displacement was likely to occur at the contact site between the anterior end of mandibular defect and the titanium plate. In conclusion, these findings indicate that mandibular body reconstruction using bicortical titanium screws and titanium plate is relatively stable, but the titanium plate fixed at the anterior part of the mandibular angle is prone to breakage.     

三维有限元分析脊柱中胸段(T6-8)结核经肋椎单元植入物固定的应力变化

背景：目前关于T₆-T₇-T₈经肋椎单元固定缺乏相关生物力学模型,另外关于临床断钉断棒、骨融合质量差和邻近节段退变的原因及合理解释,也无基础研究参数支持。 目的：建立T_6-8结核病灶清除植骨、后路经肋椎单元固定系统三维有限元模型,分析其所受应力并对其进行改进。 方法：获取1例男性(身高172 cm,体质量71 kg,年龄39岁)T₇椎体结核病患进行螺旋CT扫描,将所得数据导入计算机,通过Mimics 13.0软件和Ansys 11.0有限元软件建立T_6-8后路病灶清除植骨、经肋椎单元固定系统三维有限元模型,并在椎体上表面施加500 N压力和10 N•m的力矩模拟脊柱前屈、后伸、侧屈3种生理载荷,观察不同载荷下固定器械的应力分布,并对其进行比较。 结果与结论：在前屈和后伸运动状态下,螺钉尾部是应力最为集中的部位,上位螺钉大于中、下位螺钉;对于连接棒,中部总是小于下端,且中部应力为零;侧弯位,上、中位螺钉尾部应力相当,连接棒单侧应力相当。同一部位在3种运动状态下比较,连接棒中段在侧弯运动下应力增大,下位螺钉末端在3种运动状态下应力相当。提示T_6-8运动节段后路椎间植骨、经肋椎单元内固定的结核患者在做前屈、后伸、侧弯这3种运动时,上位螺钉尾部较中、下位螺钉更容易发生疲劳性断裂;在做前屈、后伸运动时连接棒下端和在做侧弯运动时连接棒中段更容易发生疲劳性断裂。 中国组织工程研究杂志出版内容重点：人工关节;骨植入物;脊柱;骨折;内固定;数字化骨科;组织工程全文链接：     

足部结构有限元模型的建立与应用

BACKGROUND: The finite element analysis used to study the biomechanical properties of foot structure contributes to overcome the disadvantages of traditional mechanical analysis of specimens. OBJECTIVE:To summarize some representative finite element models of the foot and review the establishment methods of finite element models of the foot with biomechanical properties. METHODS: A computer-based online search was conducted in CNKI, Wanfang and PubMed databases by using the key words of “finite element model, biomechanic, foot structure” from 1999 to 2015. The language was limited to both Chinese and English. Establishment methods of finite element models of the foot structure containing obtaining of model establishment data, establishment of solid model, setting methods of properties of model materials. The application of finite element analysis of the foot structure in sports biomechanics and medical orthotics was summarized to point the characteristics and disadvantages of finite element analysis application in biomechanics. RESULTS AND CONCLUSION: An increasing number of studies on foot biomechanics provide the platform for finite element analysis of the foot applied in biomechanical analysis. Many key technologies, including self-adaption image segmentation method, hexahedron grid product method and establishment of finite element models with various materials have to be utilized to converse the medical images into digital models of finite element analysis during establishment of finite element models. Results of model establishment may be affected by limitation conditions, accuracy of image collection, calculation results of finite element analysis. The reliability of finite element models can be increased by modify technologies and verification methods. 中国组织工程研究杂志出版内容重点：组织构建;骨细胞;软骨细胞;细胞培养;成纤维细胞;血管内皮细胞;骨质疏松;组织工程     

种植体结构改变对种植体-骨界面皮质骨区应力影响的三维有限元分析

背景：种植体-骨界面的生物力学效应是骨吸收重要的影响因素之一。模仿天然牙周膜的新结构种植体或可改善其界面应力的分布情况。 目的：探讨不同的咬合负载条件下,改变传统种植体内部结构对种植体-骨界面皮质骨区应力分布、峰值的影响,为新结构种植体的优化设计及临床应用提供理论依据。 方法：用Pro/ENGINEER软件建立新结构的种植体(模型A)与无螺纹的传统柱状种植体(模型B)的数字模型,采用Ansys软件分析在相同骨质及相同受力环境下种植体-骨界面皮质骨区应力峰值、应力带分布的变化规律。 结果与结论：垂直加载时,模型A在不同受力大小时应力峰值均较模型B降低17.54%;45°加载时,模型A应力峰值较模型B降低(2.59%),模型B的高应力区向颊侧集中趋势明显。咀嚼模拟加载时,模型A的应力峰值均较模型B低,其差值在施力方向与种植体轴向夹角(β)等于12°时最大(0.353 2 MPa),在β > 12°后逐渐减小;并且模型A在促进骨组织生长最适应力峰值、维持骨组织健康应力峰值两个量化指标中,均比模型B适用角度范围大(A：0°-28°,0°-58°;B：0°-24°,0°-56°)。提示优化设计种植体结构的改变可改善种植体-骨界面皮质骨区的应力分布,降低应力峰值,可在更大范围内降低骨皮质吸收的风险。 中国组织工程研究杂志出版内容重点：生物材料;骨生物材料; 口腔生物材料; 纳米材料; 缓释材料; 材料相容性;组织工程     

上颌中切牙角度基台不同载荷的三维有限元优化分析

背景：口腔种植修复中,种植体中基台角度的优化设计对骨吸收有重要影响,同时患者的高用力也对骨质的吸收重建有着重要影响。 目的：利用Ansys Workbench 13.0软件对上颌骨前牙区进行优化设计模型,探讨中切牙角度基台不同载荷对皮质骨和松质骨应力大小的影响。 方法：建立圆柱状V形螺纹种植体的上颌骨骨块三维有限元模型,设定基台角度为0°,5°,10°,15°,20°、25°,30°,设定加载应力为90,105,120,135,150,165,180,195,210 N。在种植体上模拟中切牙咬合,在修复体正中进行颊舌向力学加载,观察基台角度和加载应力变化对颌骨Von Mises应力峰值的影响。 结果与结论：单因素影响下,以基台角度为变量逐渐增加时,在唇腭侧向加载中皮质骨和松质骨的Von Mises应力峰值增幅分别为60.63%和69.30%;以加载应力为变量逐渐增加时,在颊舌向加载中皮质骨和松质骨的Von Mises应力峰值增幅分别为68.74%和69.30%。在基台角度和加载应力交互作用下,当加载应力小于  150 N,同时基台角度小于25°时,对颌骨Von Mises应力峰值响应曲线的切线斜率位于-1至0之间。所以从力学分析看来,松质骨的应力大小更易受到基台角度和加载应力的影响,螺纹种植体最佳的基台角度设计应小于25°,咬合力应小于150 N。中国组织工程研究杂志出版内容重点：生物材料;骨生物材料; 口腔生物材料; 纳米材料; 缓释材料; 材料相容性;组织工程     

临床骨科中应用的有限元分析法：新理论与新进展

BACKGROUND: The limitations of computer technology in the study of bone biomechanics and the prediction of bone fixation strength, stability, fatigue damage and life expectancy are more difficult.     

不稳定股骨转子间骨折不同内固定方式的三维有限元分析

BACKGROUND: The morphological and mechanical transfers of unstable intertrochanteric fractures were complicated, so it is difficult to analyze the biomechanical characteristics of the common experimental methods in a comprehensive way. Moreover, the high cost, long cycle and poor repeatability of common tests limit its application in biomechanics.      

踝关节胫骨远端关节面缺损生物力学特征的三维有限元分析

BACKGROUND: Studies found that three-dimensional finite element analysis can be used in the study of ankle biomechanics, but research on distal tibial articular surface defect was few.