垂直载荷下分割式可摘局部义齿与套筒冠义齿的有限元分析

目的研究并比较分割式可摘局部义齿与缓冲圆锥型套筒冠义齿在垂直载荷下的应力情况。方法选择上颌双侧第二前磨牙、第一磨牙缺失并伴有基牙有Ⅰ度松动的患者1名,通过螺旋CT扫描,利用Materialise Mimics、Pro/Engineer WF 2.0软件和ANSYS Workbench软件建立精确的上颌三维有限元模型,并在其上进行垂直方向加载,分析比较分割式可摘局部义齿与缓冲圆锥型套筒冠义齿缺牙区黏膜及基牙牙周膜应力情况。结果垂直载荷下,分割式可摘局部义齿缺牙区黏膜所受von Mises力值大于缓冲圆锥型套筒冠义齿缺牙区黏膜所受力值;分割式可摘局部义齿基牙牙周膜von Mises力值接近或小于缓冲圆锥型套筒冠义齿基牙牙周膜所受力值。结论在垂直载荷下,通过与缓冲圆锥型套筒冠义齿相比,分割式可摘局部义齿具有减少基牙受力,保护基牙的功能。     

分割式及普通可摘局部义齿缺牙区黏膜的三维有限元分析

目的:研究并比较戴用分割式可摘局部义齿与普通可摘局部义齿在不同载荷下缺牙区黏膜的应力情况。方法:选择上颌第二双尖牙、第一磨牙缺失伴基牙有I度松动的患者1例,通过螺旋CT扫描获得上颌二维断层图像。在Pro/Engineer中进行模型的建立,然后导入ANSYS Workbench软件中,进行网格化分和三维有限元分析。结果:斜向、垂直载荷下,戴用分割式可摘局部义齿与戴用普通可摘局部义齿的缺牙区黏膜Vonmises力的数值范围有明显差异。水平载荷下,二者有一定差异。3种载荷下均为戴用分割式可摘局部义齿较大。3种载荷下二者的Von mises力分布情况相似。结论:从生物力学的角度证明,对基牙有I-II度松动以及牙周健康状况不佳的患者,行分割式可摘局部义齿修复是可行的。可以认为,分割式可摘局部义齿有效地起到了保护基牙的作用。     

口腔生物力学

弹性模量和初始应力对种植体骨界面应力分布影响的三维有限元分析；通用混合型复合树脂收缩应力的光弹分析；不同加载条件下RPI卡环固位可摘局部义齿的三维有限元分析；利用Matlab和Pro／E软件辅助建立桩核冠的三维有限元模型；纳米（PMMA／蒙托土）义齿基托复合材料力学性能的研究；冷冻／冷冻干燥处理对犬下颌骨生物力学性能的影响。[编者按]     

���Kennedy�����ժ�������Ԫģ�͵Ľ���

目的    建立下颌KennedyⅠ类可摘局部义齿的三维有限元模型,为其设计提供生物力学基础。方法    在2008年6月山东大学附属千佛山医院口腔科常规体检人群中选取1名男性志愿者,年龄55岁,下颌双侧后牙游离缺失,余留前牙无拥挤,咬合关系正常。通过螺旋CT扫描与计算机辅助设计（CAD）技术及Unigraphics、MSC.MARC软件结合的方法,建立下颌KennedyⅠ类可摘局部义齿的三维有限元模型。结果    建成双侧后牙游离缺失的下颌骨及其可摘局部义齿的三维有限元模型,共有单元36 968个,节点9553个,模型可以根据需要任意进行旋转和缩放。 结论    CT扫描与CAD技术联合应用建立双侧后牙游离缺失的下颌骨及其可摘局部义齿三维有限元模型的方法切实可行。     

可摘局部义齿各部件三维有限元模型库的建立

目的 建立可摘局部义齿各部件的三维有限元模型库。方法：在正常牙颌组织及可摘局部义齿三维几何学模型库的基础上，利用Powershape、Pro/E和Ansys 5．5软件，通过数据转换、模型分割修整、重建，分别建立各模型单元体，并在整体模型中连接、修整，最终生成各类有限元模型库。结果：建立了包括(牙合)支托、卡环、基托、人工牙、连接体等共计200余个有限元单元体，分类生成8类有限元模型库。结论：各类模型具有良好的几何学形态，在整体模型中组合完好，调用、编辑便捷。     

可摘局部义齿

套筒冠可摘活动义齿修复后出现的问题及处理；上颌可摘局部义齿修复对辅音声学特征的影响；上颌肯氏Ⅰ类牙列缺损义齿修复对元音的影响；牙列缺损患者三维数字化牙颌模型数据库的建立。     

不同补偿曲线的上颌全口义齿三维有限元模型的建立

目的：建立上颌全口义齿不同补偿曲线的有限元模型,为分析补偿曲线对上颌全口义齿基托应力分布的影响奠定基础。方法：采用层切法、CT扫描等方法获得上颌全口义齿、上颌骨的断面形态数据,用Surfacer软件处理数据,导入ANSYS软件建立CAD模型,最后常规计算。结果：建立了不同补偿曲线的上颌全口义齿的三维有限元模型。结论：该模型可用于探讨补偿曲线对上颌全口义齿应力分布的影响。     

集成于可摘局部义齿专家系统的二维有限元分析方法

目的:在可摘局部义齿专家系统中,自动应用有限元分析方法进行应力分析.方法:建立一种特殊的二维有限元模型及相应的中间转换软件,将可摘局部义齿专家系统给出的修复设计方案,自动转换生成有限元分析的数据文件,从而进行有限元应力分析.结果:在可摘局部义齿专家系统中实现了自动的有限元应力分析.结论:特殊结构的有限元模型,可自动适应义齿设计专家系统针对各种牙列缺损情况给出的修复设计方案进行有限元应力分析.     

上颌腭骨三维有限元模型的建立

目的建立腭骨三维有限元模型,为进一步研究腭部种植支抗进行上颌扩大的可行性及其与牙支抗的对比研究建立数学模型基础。方法采用螺旋CT断层扫描成年人上颌骨,计算机图像处理和转录技术,自编程序和ANSYS软件相结合,将CT扫描图像转换为可用于有限元建模的数值图像。结果建立了上颌腭骨、部分颧弓根部的三维有限元模型。结论借助螺旋CT扫描技术和ANSYS有限元分析软件,建立上颌腭骨的有限元模型是切实可行的。该模型为上颌腭部种植支抗的生物力学研究提供了一个平台。     

基牙牙周损伤影响可摘局部义齿应力分布的三维有限元分析

目的 探讨三维红外扫描用于可摘局部义齿三维有限元建模的可行性,并分析基牙牙周损伤对可摘局部义齿应力分布的影响,以期为临床提供参考.方法 利用齿科非接触式红外扫描仪和Simpleware软件对下颌肯尼迪分类法Ⅱ类缺损的可摘局部义齿进行三维建模,构建正常牙槽骨组、牙槽骨吸收组和牙槽骨吸收伴牙周膜增宽组三维有限元模型.使用Abaqus有限元分析软件,研究垂直加载和颊侧45°加载条件下3组牙槽骨的应力分布.结果 垂直加载和颊侧45°加载条件下,3组模型均在义齿近中基牙和剩余牙槽嵴远中出现应力集中;牙槽骨吸收伴牙周膜增宽组近中基牙的应力最大(分别为3.57和2.50 MPa),其次为牙槽骨吸收组(分别为3.21和2.41 MPa),正常牙槽骨组最小(分别为2.63和1.79 MPa).颊侧45°加载时3组模型剩余牙槽嵴远中颊侧和远中位点上的应力值均大于垂直加载.结论 基于三维红外扫描的有限元建模方法是可摘局部义齿有限元应力分析有效的建模方式.     

Effectiveness of Computer-Aided Removable Partial Denture Design

Purpose Computer programs have been developed for removable partial denture (RPD) design, but their educational impact has never been investigated. This study measured the effectiveness of computer-based RPD design simulations in a traditional RPD design course for second-year dental students. Materials and Methods Thirty-six students were randomly assigned to four groups, two simulation and two control groups, at the beginning of the RPD design module. A cross-over design compared the two strategies during laboratory exercises. First, the simulation group worked with the simulation, while the control group met in small-group seminars with faculty. Post-test 1 was given, and then students switched teaching methods and post-test 2 was given. Each post-test had two parts. Part 1 involved designing an RPD based on specific patient criteria. Part 2 involved choosing the more correct of the two designs. Results Results showed a significant difference (p= .0072) in two of four test groups. Although it was an initial evaluation, the computer simulation was shown to be equivalent to faculty-led small-group seminars. Students also responded positively to a questionnaire on their perceived effectiveness of the simulations. Conclusions The results suggest that RPD design can be taught as effectively with computer-based simulations as with faculty-led seminars.     

应用三维激光扫描技术建立下颌固定义齿的三维有限元模型

目的:建立下颌固定义齿的三维有限元模型。方法:选择带有牙根的下颌固定义齿模型进行三维激光扫描,获得表面三维点云数据,经过软件处理形成三维有限元模型。结果:所建立的下颌固定桥模型仿真效果好、精确度高,基本满足了口颌系统中力学分析的需要。结论:利用三维激光扫描技术可以快捷、准确地建立三维几何模型和有限元模型,以满足临床工作的需要。     

3种印模材料制取活动义齿模型的三维精度比较

目的：评价硅橡胶类、琼脂类和藻酸盐类(水粉调料型)等3种印模材料的取模精度。方法：分别用3种印模材料制取10个同一实验主模具的人造石模型，用电子游标卡尺测量主模具和石膏模型上各标志点的距离，精度为0.01mm，所得数据进行统计分析。结果：硅橡胶类印模材料制取的石膏模型线性变化率最小且比主模型稍大，与琼脂类和藻酸盐类印模材料制取的印模在三维尺寸变化率方面无显著差异。结论：硅橡胶类印模材料的取模精度最高，琼脂类印模材料因取模精度高，操作比较简单，且价格易于接受等优点，值得在临床推广。     

上颌游离端可摘局部义齿修复基牙的三维有限元应力分析

目的：本研究采用三维有限元动态分析法，对上颌游离端可摘局部义齿修复双尖牙基牙进行应力分析。方法：利用工程扫描系统、计算机辅助设计软件和有限元程序，模拟天然牙齿建立三维有限元模型。根据基牙的受力情况制作7种实验模型，并结合He支托的不同设计，常规载荷下，对基牙在近远中、颊舌向和咬合方向进行应力分析。结果：1)游离末端基牙远中牙颈部为最大应力区。2)远中He支托对基牙的损伤较近中殆支托大，He支托设计位置越向近中移动，其对基牙的损伤越小。3)颊舌向外力和近远中方向外力对基牙造成的损害比来自咬合方向明显大。结论：上颌游离可摘局部义齿，使用近中He支托，远中固位臂加远中邻面板的类似设计更有效地减少不良应力对基牙带来的伤害。     

观测器在可摘局部义齿修复中的临床应用调查

目的：探讨在可摘局部义齿修复中应用观测器的重要性。方法：分别用观测法和目测法设计和制作可摘局部义齿，一年半后从支架的缺陷、口腔支持组织的生物学行为和义齿的功能三大方面评价两组义齿的临床疗效。结果：在义齿的固位，稳定，取戴，支持组织的炎症，患者的舒适度等方面，观测法组均优于目测法(P＜0．05)，两组在咀嚼功能方面无显著性差异(P＞0．05)。结论：在修复中应常规采用观测器来设计和制作可摘局部义齿。     

弹性树脂结合铸造支架可摘义齿修复牙周病患者缺牙的临床评价

目的：探讨弹性树脂与铸造支架联合修复牙周病患者缺牙的临床效果。方法：采用弹性树脂做唇（颊）侧基托及前牙、前磨牙唇（颊）侧固位体,后牙及舌（腭）侧采用铸造支架,设计联合可摘局部义齿,修复28例牙周病缺牙患者,共35件修复体,戴用1年后进行临床评价。结果：弹性树脂结合铸造支架可摘义齿在美观舒适性、固位力、咀嚼功能、食物嵌塞、基牙情况等方面较传统义齿有明显改善。结论：将弹性树脂与铸造支架结合起来修复牙周病缺牙,能很好的解决其美观和功能的问题,是一种较好的修复方法。     

Using Intraoral Scanning Technology for Three‐Dimensional Printing of Kennedy Class I Removable Partial Denture Metal Framework: A Clinical Report

Removable partial dentures (RPDs) are used to restore missing teeth and are traditionally fabricated using the lost‐wax casting technique. The casting process is arduous, time‐consuming, and requires a skilled technician. The development of intraoral scanning and 3D printing technology has made rapid prototyping of the RPD more achievable. This article reports a completed case of direct fabrication of a maxillary RPD metal framework (Kennedy Class I) using intraoral scanning and 3D printing techniques. Acceptable fit and satisfactory clinical outcome were demonstrated. Intraoral scanning and 3D printing for fabrication of the RPD metal framework is a useful alternative to conventional impression and casting techniques, especially for patients suffering from nasal obstruction or intolerance.     

Finite Element Stress Analysis of Tooth-to-Implant Fixed Partial Denture Designs

Purpose The purpose of this study was to conduct a three-dimensional finite element stress analysis to compare models representing a natural tooth and an integrated implant connected with rigid and nonrigid prostheses. Materials and Methods The mathematical models described an integrated implant connected to a second premolar tooth with a three-unit metal-ceramic fixed partial denture. In one model, the tooth and implant were rigidly connected, and in the other, a nonrigid connection was assumed. From a simulated vertical load the computer generated resultant stress contours and values (compressive and tensile) in horizontal and vertical dimensions. Results A comparison of the magnitude and pattern of stresses generated in the models shows minimal differences. Although the maximum stress values were slightly higher in some areas of the rigid prosthesis model, the differences were negligible. Conclusions Based on the similarities in both the patterns of stress contours and the stress values generated in the two models, advocating a nonrigid connection because of a biomechanical advantage may be erroneous.     

Effectiveness of Adhesive Systems for a Co–Cr Removable Partial Denture Alloy

Purpose In vitro bond strengths of traditional denture base acrylic resin (Lucitone 199) to a cobalt-chromium partial denture alloy (J.D. Partial Denture Alloy) were tested using two surface pretreatments (sandblast, sandblast and electrochemical etch) with three adhesive primers: Lee Metal Primer, Acrylic Solder, and CR Inlay cement. A sandblasted group with no primer served as the control. Materials and Methods The alloy specimens (8.0-mm bonding diameter) were cast and invested to receive a traditional denture base resin after surface treatments (sandblasted, and sandblasted-electrochemically etched) and application of adhesive primers. The bonded specimens were stored in distilled water at 37°C for 24 hours and divided into two groups. The first group was debonded in tension on a testing machine at a cross-head speed of 0.05 cm/min. The second group was subjected to thermocycling of 1,000 cycles and then tested for tensile bond strength. The force at which the bond failed was recorded, and the bond strength was calculated in megapascals (MPa). The sites of bond failure were examined, quantified under (20x) magnification, and recorded. Ten specimens were evaluated for each experimental condition for a total of 160 specimens. Data were analyzed by ANOVA with a factorial design. Means were compared by Tukey intervals at the 0.05 significance level. Results Significant differences in bond strength were observed, with primers being the most important factor, followed by pretreatment and storage and thermocycling with significant interactions. Sandblasted-electrochemically etched alloy with primers more effectively enhanced bond strength of the denture base resin to the treated alloy than sandblasted alloy with primers. Thermocycling had a greater effect on bond strength of the specimens with Acrylic Solder when compared with Lee and CR Inlay primers. The highest bond strengths (>18.0 MPa) were observed for the conditions involving electrochemical etching and the priming with CR Inlay cement (both after 24 hours and thermocycling of 1,000 cycles). For primed specimens, the bond failures occurred cohesively within the primers or the denture resin and adhesively between the primers and the denture base resin, or between primers and alloy. For nonprimed, the bond failures occurred adhesively at the denture base resin-metal interface. Conclusions Nonprimed specimens (both sandblasted and electrochemically etched) had lowest bond strength (0.4 ± 0.1 MPa; 0.3 ± 0.4 MPa). The bond strengths of the primed treated specimens were improved significantly. The CR Inlay-treated specimens exhibited the highest bond strength (20.6 ± 6.3 MPa). After thermocycling for 1,000 cycles, the bond strengths of the specimens were significantly lower than the bond strengths of the specimens after 24 hours.     

348例老年人活动义齿修复临床探讨

目的了解老年修复患者口腔情况,探讨老年人牙列缺失缺损后的修复特点.方法分析348例老年人牙列缺损缺失的情况,采取不同方法进行修复,并进行5年随访.结果老年人牙列缺失缺损在注意咬牙合重建、抬高咬合、防止食物嵌塞情况下进行活动义齿修复.结论 活动义齿是老年人修复治疗的主要方法,老年人活动义齿修复应注意咬合重建,防止食物嵌塞.