- 作者：Eliane Placido ; Josete B.C. Meira ; Raul Gonzá ; lez Lima ; Antonio Muench ; Roberto Martins de Souza ; Rafael Yagc ; e Ballester
- 关键词：Dental material ; Finite element analysis ; Dental bonding ; Bond strength test ; Materials testing
- 刊名：Dental Materials
- 出版年：2007
- 期刊代码：29_01095641
- 类别：ms
- 出版时间：September 2007
- 卷：23
- 期：9
- 页码：1086-1092
- 文件大小：599 K
class="h4">Methods
Two-dimensional plane strain finite element analysis was performed using MSCPatran® and MSCMarc® softwares. Model configurations were based on published experimental shear and micro-shear test set-ups and material properties were assumed to be isotropic, homogeneous and linear-elastic. Typical values of elastic modulus and Poisson's ratios were assigned to composite, dentin and adhesive. Loading conditions considered a single-node concentrated load at different distances from the dentin-adhesive interface, and proportional geometry (1:5 scale, but fixed adhesive layer thickness in 50 bc;m) with similar calculated nominal strength. The maximum tensile and shear stresses, and stress distribution along dentin-adhesive interfacial nodes were analyzed.
class="h4">Results
Stress distribution was always non-uniform and greatly differed between shear and micro-shear models. A pronounced stress concentration was observed at the interfacial edges due to the geometric change: stress values farther exceeded the nominal strength and tensile stresses were much higher than shear stresses. For micro-shear test, the relatively thicker adhesive layer and use of low modulus composites may lead to relevant stress intensification. An appropriate loading distance was established for each test (1 mm for shear and 0.1 mm for micro-shear) in which stress concentration would be minimal, and should be standardized for experimental assays.
class="h4">Significance
The elastic modulus of bonded composites, relative adhesive layer thickness and load application distance are important parameters to be standardized, once they influence stress concentration.