Influence of cement on a restored crown of a first premolar using finite element analysis.
OBJECTIVE
The purpose of this study was to examine the influence of the elastic modulus of cement and luting thickness on the resulting stresses in an axially loaded crown cemented onto a first premolar. A comparison of these stresses was also made with the strength of the constituent materials making up the crown.


METHODS
Examination of the stresses on a restored crown was conducted using finite element analysis. Eight different axisymmetric models containing combinations of In-Ceram or gold coping, using adhesive resin or zinc phosphate cement as the luting agent, with thicknesses of either 0.05 or 0.1 mm were analyzed.


RESULTS
The peak tensile principal stresses in the porcelain remained below its material fracture strength. The same was true for the peak stress in the adhesive resin compared to its fracture and chemical bond strength. This was not the case for zinc phosphate. The influence of the luting agent's elastic modulus on the stresses in the crown was minor, and the influence of luting thickness was even less.


CONCLUSIONS
The role of the luting agent was primarily one that effectively transferred the resulting stresses between the relatively stiff coping and underlying dentin. There was no evidence of the luting agent itself playing a significant role in resisting deflection from the applied force.
Proos
Kaarel A
KA
School of Aerospace, Mechanical and Mechatronic Engineering and Faculty of Dentistry, University of Sydney, Biomaterials Science Research Unit, National Innovation Centre, Eveleigh, New South Wales, Australia.
Swain
Michael V
MV
Ironside
Jim
J
Steven
Grant P
GP
D000537:Aluminum Oxide / Q000737:chemistry; D001641:Bicuspid; D003198:Computer Simulation; D003442:Crowns; D003738:Dental Cements / Q000737:chemistry*; D003776:Dental Porcelain / Q000737:chemistry; D003804:Dentin / Q000502:physiology; D004548:Elasticity; D020342:Finite Element Analysis; D006047:Gold Alloys / Q000737:chemistry; D006801:Humans; D008954:Models, Biological; D019279:Resin Cements / Q000737:chemistry; D013314:Stress, Mechanical; D013499:Surface Properties; D015036:Zinc Phosphate Cement / Q000737:chemistry
D003738:Dental Cements; D006047:Gold Alloys; D019279:Resin Cements; D003776:Dental Porcelain; C070870:In-Ceram; D015036:Zinc Phosphate Cement; D000537:Aluminum Oxide