Shinya Akikazu, Yokoyama Daiichiro, Lassila Lippo V J, Shinya Akiyoshi, Vallittu Pekka K
Deptartment of Crowns and Bridges, Schood of Life Dentistry at Tokyo, The Nippon Dental University, Chiyoda-ku, Tokyo, Japan.
J Adhes Dent. 2008 Oct;10(5):365-71.
The aim of this study was to evaluate stress distribution in anterior adhesive fixed dental prostheses (FDP) and at the tooth/framework interface. Metal (M-FDP) and glass fiber-reinforced composite (FRC-FDP) frameworks were compared.
The design of the FDP consisted of retainers on a maxillary central incisor and canine with a pontic of a lateral incisor. Two different framework materials were compared: isotropic Au-Pd alloy and anisotropic continuous unidirectional E-glass FRC. Veneers in both cases were made of isotropic veneering hybrid composite. A 3-dimensional finite element model of a 3-unit FDP loaded with 154 N (at a 45-degree angle to the incisal edge of the pontic) was used to analyze stress distribution in the FDP and at the adhesive interface. A finite element analysis was used in calculation of the maximum principal stress and displacement.
The maximum displacement of FRC-FDP was higher than that of M-FDP. Stress concentrations were located equally in the connectors and at the occluding contact points in both framework types. Maximum principal stress of FRC-FDP was lower than that of M-FDP. Stress analysis further indicated that the maximum stress in the luting cement interface of FRC-FDP was located at the middle part of the retainers, whereas in the M-FDP, the maximum stress was located at the marginal edge of the retainers.
The FE model revealed differences in displacement and stress distribution between metal and FRC frameworks of FDP. The general observation was that FRC-FDP provided more even stress distribution from the occluding contact point to the cement interface than did M-FDP.
本研究旨在评估前牙粘结固定义齿（FDP）及其与牙齿/支架界面处的应力分布情况。对金属（M-FDP）和玻璃纤维增强复合材料（FRC-FDP）支架进行了比较。
FDP的设计包括上颌中切牙和尖牙上的固位体以及侧切牙的桥体。比较了两种不同的支架材料：各向同性的金钯合金和各向异性的连续单向E玻璃纤维增强复合材料。两种情况下的 veneers均由各向同性的 veneering混合复合材料制成。使用一个加载154 N（与桥体切缘呈45度角）的三单位FDP三维有限元模型来分析FDP及其粘结界面处的应力分布。采用有限元分析计算最大主应力和位移。
FRC-FDP的最大位移高于M-FDP。两种支架类型在连接体和咬合接触点处的应力集中情况相同。FRC-FDP的最大主应力低于M-FDP。应力分析进一步表明，FRC-FDP粘结剂界面处的最大应力位于固位体中部，而在M-FDP中，最大应力位于固位体边缘。
有限元模型揭示了FDP的金属和FRC支架在位移和应力分布上的差异。总体观察结果是，与M-FDP相比，FRC-FDP从咬合接触点到粘结剂界面提供了更均匀的应力分布。
