Skip to main content
U.S. flag

An official website of the United States government

Official websites use .gov
A .gov website belongs to an official government organization in the United States.

Secure .gov websites use HTTPS
A lock ( ) or https:// means you’ve safely connected to the .gov website. Share sensitive information only on official, secure websites.

Lifetime-Limiting Strength Degradation From Contact Fatigue in Dental Ceramics



Yeon-Gil G. Jung, I M. Peterson, D H. Kim, Brian R. Lawn


Indentation damage and associated strength degradation from multi-cycle contacts with spherical indenters in water are evaluated in four dental ceramics, to examine the hypothesis that the lifetimes of dental restorations are limited by the accumulation of contact damage during oral function. Four dental ceramics are investigated: Aaesthetic@ ceramics, porcelain and micaceous glass-ceramic (MGC); Astructural@ ceramics, glass-infiltrated alumina and yttria-stabilized tetragonal zirconia polycrystal (Y-TZP). Initial damage is highly dependent on microstructure, consisting primarily of cone cracks (Abrittle@ response) in the porcelain and cumulative subsurface deformation (Aquasi-plastic@ response) in the MGC and Y-TZP, with alumina an intermediate case. However, at large numbers of contact cycles all materials show an abrupt transition in damage mode, consisting of strongly enhanced damage within the contact area and attendant initiation of radial cracks without. This transition in damage mode is not observed in comparative static loading tests, attesting to a strong mechanical component in the fatigue mechanism. The radial cracks, once formed, lead to rapid degradation in strength properties, signalling the end of useful lifetime of the material. Strength degradation from multi-cycle contacts occurs in the porcelain and glass-ceramic after /_104 cycles at loads as low as 200 N; comparable degradation in the alumina and Y-TZP requires loads higher than 500 N, well above the clinically significant range.
Journal of Dental Research
No. 2


contact fatigue, damage accumulation, dental ceramics, fracture, strength degredation


Jung, Y. , Peterson, I. , Kim, D. and Lawn, B. (2000), Lifetime-Limiting Strength Degradation From Contact Fatigue in Dental Ceramics, Journal of Dental Research (Accessed July 15, 2024)


If you have any questions about this publication or are having problems accessing it, please contact

Created February 1, 2000, Updated February 19, 2017