Finite element analysis model to simulate the behavior of luting cements during setting.
OBJECTIVE
Besides the fixation of the restoration, an important function of dental luting cements is to seal the gap between tooth and restoration. However, as a result of adhesion, curing contraction is hindered, creating stresses. To maintain the seal these stresses neither exceed the bond nor the cohesive strength of the cement. The aim of this study was to evaluate a rather simple model, which mimics the setting behavior of luting cements based on the division of the setting process into a liquid, visco-elastic and elastic phase, for its suitability to predict in Finite Element Analysis (FEA) the magnitude of the setting stresses occurring clinically.


METHODS
Commercial luting cement, RelyX ARC, was used in this study. In a dynamic test set-up the stresses, the elastic strain, and the shrinkage were determined. Two layers with different thicknesses and different ratios between bonded and free surface (C-factor) were examined. The parameters were used in three-dimensional FEA models. The experimental contraction stresses were compared with the results of the FEA.


RESULTS
In cement layers with uniform layer thickness, it is possible to predict the contraction stresses with the found parameters. The smallest plastic deformations and contraction stresses were found in the thinnest layer. The studied model was reliable in predicting the experimental stresses.


CONCLUSIONS
The results of this study may be used for the prediction using FEA of the actual stresses occurring in dental restorations.
De Jager
Niek
N
Department of Dental Materials Science, ACTA, Louwesweg 1, 1066 EA Amsterdam, The Netherlands. n.de.jager@acta.nl
Pallav
Prem
P
Feilzer
Albert J
AJ
D017438:Bisphenol A-Glycidyl Methacrylate; D003187:Compliance; D003799:Dental Stress Analysis / Q000379:methods*; D004548:Elasticity; D020342:Finite Element Analysis; D006244:Hardness; D016014:Linear Models; D044367:Phase Transition; D011092:Polyethylene Glycols; D011109:Polymethacrylic Acids; D019279:Resin Cements; D013314:Stress, Mechanical
D011109:Polymethacrylic Acids; C462240:RelyX ARC; D019279:Resin Cements; D011092:Polyethylene Glycols; D017438:Bisphenol A-Glycidyl Methacrylate