Prediction of permanent deformation in cast clasps for denture prostheses using a validated nonlinear finite element model.
OBJECTIVE
Permanent deformation is one of the most common mechanical complications that affect denture clasps. This can lead to loss of retention and stability of the prosthesis. The purpose of this study was to apply and validate a nonlinear finite element model for permanent deformation prediction in cast denture clasps. Such a model can enhance the process of design optimization and contribute to minimizing the possibility of this problem.


METHODS
Cast clasps made from Ti-6Al-7Nb, Co-Cr and Type IV gold alloys were loaded in three different directions (outside, inside and outside inclined 30 degrees ), and the resulting permanent deformation values were recorded. Nonlinear finite element analysis simulations based on the maximum distortion energy criterion for yielding, were conducted for clasp models that were reproduced according to the dimensions of each experimental specimen. Linear regression analysis for the results of the experiment and simulation was performed to verify the validity of the mathematical models.


RESULTS
Deflections required to produce specific amounts of permanent deformation were in close agreement with those recorded experimentally. The R2 value for all bending tests was 0.985 and the linear regression equation expressed in micrometers was [DeflectionFEA=0.976 (DeflectionReal)+34].


CONCLUSIONS
Permanent deformation behavior in the cast clasps with a relatively wide range of deflections (0-2 mm) can be predicted using the proposed model, which shall enhance the design optimization process of cast clasps for denture prostheses.
Department of Conservative Dentistry and Prosthodontics, Dental School, University of Jordan, Amman 11942, Jordan. anabtawime@yahoo.com
Ahmad Abdel Aziz
AA
Mahmoud
Noriyuki
N
Wakabayashi
Hidekazu
H
Takahashi
D003722:Dental Alloys; D003735:Dental Casting Technique; D016734:Dental Clasps; D019232:Dental Restoration Failure; D003799:Dental Stress Analysis / Q000379:methods*; D003781:Denture Retention / Q000295:instrumentation*; D003832:Denture, Partial, Removable; D004548:Elasticity; D020342:Finite Element Analysis; D016014:Linear Models; D008962:Models, Theoretical; D017711:Nonlinear Dynamics; D018583:Pliability
D003722:Dental Alloys