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The suitability of different FEA models for studying root fractures caused by wedge effect

✍ Scribed by Josete B. C. Meira; Mayra F. Z. Quitero; Roberto R. Braga; Eliane Placido; Flávia P. Rodrigues; Raul G. Lima; Rafael Y. Ballester


Publisher
John Wiley and Sons
Year
2007
Tongue
English
Weight
209 KB
Volume
84A
Category
Article
ISSN
1549-3296

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✦ Synopsis


Abstract

Finite element analysis (FEA) utilizing models with different levels of complexity are found in the literature to study the tendency to vertical root fracture caused by post intrusion (“wedge effect”). The objective of this investigation was to verify if some simplifications used in bi‐dimensional FEA models are acceptable regarding the analysis of stresses caused by wedge effect. Three plane strain (PS) and two axisymmetric (Axi) models were studied. One PS model represented the apical third of the root entirely in dentin (PS‐nG). The other models included gutta‐percha in the apical third, and differed regarding dentin–post relationship: bonded (PS‐B and Axi‐B) or nonbonded (PS‐nB and Axi‐nB). Mesh discretization and material properties were similar for all cases. Maximum principal stress (σ~max~) was analyzed as a response to a 165 N longitudinal load. Stress magnitude and orientation varied widely (PS‐nG: 10.3 MPa; PS‐B: 0.8 MPa; PS‐nB: 10.4 MPa; Axi‐B: 0.2 MPa; Axi‐nB: 10.8 MPa). Axi‐nB was the only model where all σ~max~ vectors at the apical third were perpendicular to the model plane. Therefore, it is adequate to demonstrate the tendency to vertical root fractures caused by wedge effect. Axi‐B showed only part of the σ~max~ perpendicular to the model plane while PS models showed σ~max~ on the model plane. In these models, σ~max~ orientation did not represent a situation where vertical root fracture would occur due to wedge effect. Adhesion between post and dentin significantly reduced σ~max~. © 2007 Wiley Periodicals, Inc. J Biomed Mater Res, 2008