用三维有限元方法对单端固定桥进行应力分析

目的：分析磨牙游离缺失单端固定桥修复的受力情况。方法：运用三维有限元应力分析法,对一侧磨牙游离缺失通过改变牙槽骨支持高度,采用不同基牙数目,不同桥体长度建立不同的单端固定桥有限元模型进行应力和位移的计算和分析。结果：较高的应力集中在游离端近中的基牙上,牙槽骨高度降低会增加基牙的移位及应力集中;单纯增加基牙的数目不会导致牙周组织中应力明显相应减少;基牙数目增加会减少修复体移位及应力集中;增加桥体长度     

单端固定桥及支持组织应力分布的研究进展

单端固定桥修复体有一定的缺陷,但是如果合理选择适应证,也是一种较好的修复方式。本文对近年来单端桥桥体的咬合力分布、基牙牙周组织、桥体、连接体应力分析以及不同载荷下桥体下组织应力应变分析的研究进展作一综述。     

用三维有限元方法对单端固定桥进行应力分析

目的分析磨牙游离缺失单端固定桥修复的受力情况。方法运用三维有限元应力分析法,对一侧磨牙游离缺失通过改变牙槽骨支持高度,采用不同基牙数目,不同桥体长度建立不同的单端固定桥有限元模型进行应力和位移的计算和分析。结果较高的应力集中在游离端近中的基牙上,牙槽骨高度降低会增加基牙的移位及应力集中;单纯增加基牙的数目不会导致牙周组织中应力明显相应减少;基牙数目增加会减少修复体移位及应力集中;增加桥体长度会引起义齿应力明显增加和向远中移位。结论游离缺失端行单端固定桥修复最好选择桥体为一个磨牙长度,且基牙数至少两个,以提高单端固定桥修复的成功率。     

三维有限元法对多基牙固定桥的应力分析

目的：分析多基牙固定桥修复的受力情况。方法：采用三维有限元方法，通过改变基牙数目与牙槽骨的支持高度建立8个有限元模型进行应力和位移的计算分析。结果：牙槽骨高度降低条件下基牙牙周膜的应力值增大；固定义齿修复后，牙周支持组织的应力值下降；随着基牙数目的增多，牙周支持组织的应力值及牙齿在垂直方向的位移值降低，但单纯增加基牙的数目不会导致支持组织的应力明显减少；与垂直向载荷相比，斜向载荷易导致支持组织的应力集中，应力分布规律有明显改变。结论：本实验结果为固定义齿的设计提供了参考依据。     

三维有限元法对多基牙固定桥的应力分析

目的：分析多基牙固定桥修复的受力情况。方法：采用三维有限元方法，通过改变基牙数目与牙槽骨的支持高度建立八个有限元模型进行应力和位移的计算分析。结果：牙槽骨高度降低条件下基牙牙周膜的应力值增大；固定义齿修复后，牙周支持组织的应力值下降；随着基牙数目的增多，牙周支持组织的应力值及牙齿在垂直方向的位移值降低，但单纯增加基牙的数目不会导致支持组织的应力明显地相应减少；与垂直向载荷相比，斜向载荷易导致支持组织的应力集中，应力分布规律有明显改变。结论：本实验结果为固定义齿的设计提供了参考依据。     

短顶帽桩核辅助支持的单端固定桥设计及应用

临床上常见上颌侧切牙因各种原因发生牙冠折断,当牙根条件不足以用桩核修复时,过去用得较多的方法,是将侧切牙牙根拔除后,利用尖牙作单端固定桥修复。但是,存在一些问题不能很好的解决,如侧切牙区牙槽骨的吸收,影响美观;单端桥杠杆力的作用,使基牙受到扭力,且单端桥的抗旋转力能力较差,影响固位。自1999年起,我们采用侧切牙牙根经完善根管治疗后,铸造短顶帽桩核与尖牙的单端桥进行修复,显著地提高了义齿的支持力、稳定性和美观,并改善了固位,取得了明显的临床修复效果。本文旨在介绍铸造桩核与单端桥联合进行修复的技术,并评价其应用的效果。     

下颌后牙固定桥支持骨组织应力的三维有限元法分析：Ⅰ.固定桥 …

目的：研究下颌后牙固定桥基牙周围牙槽骨表面的应力状态。方法：以成人下颌骨为解剖学基础,建立固定桥及基牙支持组织的三维有限元模型。分别在６种垂直向载荷和１种水平向载荷条件下,计算出基牙周围牙槽骨表面的最大主应力、最步主应力值。结果：垂直向载荷下,应力集中在根尖和颈部牙槽骨,颈部主要为拉应力,根尖区均为压应力;双尖牙周围牙槽骨应力最大值约为的２．１倍;水平向载荷下应力明显增加,约为垂直向载荷的３．５倍     

下颌后牙固定桥支持骨组织应力的三维有限元法分析：Ⅱ.固定桥 …

目的：观察固定桥桥体下皮质骨应力的分布。方法：建立固定桥及其支持组织的三维有限元模型,分别在垂直向和水平向共６种载荷下,用三维有限元法计算出固定桥桥下上质骨的最大主应力和最小主应力值。结果：修复前缺牙区皮质骨存在极小的应力,固定桥修复后,应力有所增加,但仅为基牙牙槽骨应力的９．５％（垂直向载荷）和２．２％（水平向载荷）。结论：固定桥桥体下皮质骨的应力极小,固定桥所受的力绝大部分由基牙牙周支持组织承     

改良式烤瓷粘接桥的临床研究

目的研究改良式烤瓷粘接桥的修复效果。方法2000—2001年选择100例前牙或单个后牙缺失的患者,采取改良式烤瓷粘接桥修复。结果120个修复体中,15个松动脱落,5个有继发龋,8个有基牙变色。结论改良式烤瓷粘接桥是一种较好的修复方式,应严格选择适应证,合理设计修复体。     

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。     

The all-ceramic, inlay supported fixed partial denture. Part 2. Fixed partial denture design: a finite element analysis

The clinical use of all-ceramic crowns and fixed partial dentures has seen widespread adoption over the past few years due to their increasing durability and longevity. However, the application of inlays as an abutment design has not been as readily embraced because of their relatively high failure rates. With the use of an idealized inlay preparation design and prosthesis form which better distributes the tensile stresses, it is possible to utilize the inlay as support for an all-ceramic fixed partial denture. Utilizing a three-dimensional finite element analysis, a direct comparison of the inlay supported all-ceramic bridge against the traditional full crown supported all-ceramic bridge is made. The results demonstrate that peak stresses in the inlay bridge are around 20% higher than in the full crown supported bridge with von Mises peaking at about 730 MPa when subjected to theoretical average maximum bite force in the molar region of 700 N, which is similar to the ultimate tensile strengths of current zirconia based ceramics.     

A retrospective clinical evaluation of two-unit cantilevered resin-bonded fixed partial dentures

BACKGROUND: The authors conducted a study to examine the clinical performance of two-unit cantilevered resin-bonded fixed partial dentures (RBFPDs) that were inserted at The Prince Philip Dental Hospital, University of Hong Kong. METHODS: The authors recalled patients who had received two-unit cantilevered RBFPDs at least 24 months before the recall examination. The authors recorded the following data: patient's sex and age, operator's experience, prosthesis cementation date, endodontic treatment if performed, bone support, tooth mobility, the presence of shim-stock contacts on the abutment or pontic in intercuspal position, and the presence of aproximal axial contacts adjacent to the prosthesis. They also recorded the date of any debonding with subsequent treatment. They asked the patients qualitative questions about their prostheses. RESULTS: A total of 269 prostheses were placed in 214 patients and had a mean service life of 51.7 months +/- 19.5 months standard deviation, with a range of 13.2 to 141.6 months. Of 14 failed prostheses, 12 debonded, resulting in a success rate of 94.8 percent and clinical retention rate of 95.5 percent. No discernable rotation or drifting of the abutments was apparent in any of the prostheses. Overall patient satisfaction with RBFPDs was good, with an average assessment score of 8.5. CONCLUSIONS: The authors observed a 95.5 percent clinical retention rate of 269 two-unit RBFPDs, with no apparent drifting of the abutments. Longer-term follow-up studies are required. CLINICAL IMPLICATIONS: Two-unit RBFPDs are conservative and clinically retentive prostheses in the short to medium term.     

The all‐ceramic,inlay supported fixed partial denture. Part 1. Ceramic inlay preparation design: a literature review

The effect of cavity design is a controversial and underrated factor in the clinical success of ceramic inlays and inlay supported prosthesis. Many articles and studies have been conducted into the advantages and disadvantages of isolated aspects of preparation design, but lacking is a review of the most relevant papers which bring together a consensus on all the critical features. Hence, a review and analysis of cavity depth, width, preparation taper and internal line angles is warranted in our attempts to formulate preparation guidelines that will lead to clinically successful, all‐ceramic inlay restorations and ceramic inlay supported prosthesis.     

两种方法制取固定义齿印模的临床评价

目的对藻酸盐印模法和琼脂/藻酸盐联合印模法制取固定义齿印模的效果进行临床评价。方法将237例固定义齿患者分为A、B组,A组81例患者207颗基牙,采用藻酸盐印模法制取印模;B组156例患者392颗基牙,采用琼脂/藻酸盐联合印模法制取印模。用放大镜观察两组印模,记录基牙数目、印模缺陷类型与数目。结果藻酸盐印模中有118颗（57.0%）基牙存在缺陷,琼脂/藻酸盐联合印模法中有141颗（36.0%）基牙存在缺陷,二者存在显著性差异（P<0.05）。在颈缘气泡、龈沟及肩台不清晰两个方面,两种印模法存在显著性差异（P<0.05）。在颈缘处的撕裂或缺损方面,两种印模法无显著性差异。结论琼脂/藻酸盐联合印模法较藻酸盐印模法制取的印模缺陷少。     

The use of a dental implant as an abutment in three unit implant-tooth supported fixed partial denture: a case report and 32 month follow-up

The combined use of dental implants and teeth as abutments in fixed partial dentures may offer advantages to both patients and practitioners in certain clinical situations. An implant-tooth retained prosthesis may reduce surgical intervention and cost to the patient. It may also mean that anatomical restrictions to the provision of an implant-retained fixed prosthesis may be overcome. In this case report, the steps in provision of a three unit implant-to-tooth fixed partial denture are described and the treatment planning and prognosis of a restoration of this type are discussed.     

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。