The Effects of Cyclic Loading on Fracture Modes in Brittle Layer Structures: Relevance to Failure of Dental Crowns |
| Journal |
Advanced Materials Research (Volumes 41 - 42) |
| Volume |
Structural Integrity and Failure |
| Edited by |
Xiaozhi Hu, Brent Fillery, Tarek Qasim and Kai Duan |
| Pages |
21-26 |
| DOI |
10.4028/www.scientific.net/AMR.41-42.21 |
| Online since |
April, 2008 |
| Authors |
Sarah Lam,
Kimble Halliday,
Tarek Qasim
|
| Keywords |
All Ceramic Dental Crowns, Brittle Coating, Cyclic Loading, Radial Crack |
| Abstract |
The effects of cyclic loading on contact damage in curved bi-layer systems are
investigated. Dome structures consisting of glass shells, filled with epoxy resin, simulate the
essential structure of monolithic all-ceramic dental crowns on natural tooth dentine. Cyclic loading,
with only a vertical component, was carried out with the Multi-Functional Chewing Simulator
(Willytec. Munich, Germany). The specimens were tested by indentation with hard spheres of
tungsten carbide, with the load applied axially at the apex of the dome. This project reports some
new results on the effect of cyclic loading on curved bi-layer systems. In addition, the effect of
aqueous environments is addressed. In both air and water tests, observations taken throughout the
cyclic loading course indicated that the outer cone cracks inhibited the propagation of radial cracks.
Results confirm that crack initiation occurred more rapidly in wet conditions of testing,
emphasizing the influences of the moist environment of the oral cavity. Furthermore, the
experiments took into account the evolution of inner cone cracks observed in wet cyclic loading
tests. The new results are important since nearly all-dental crowns exhibit some curvature. The
implications of the results on the failure of dental crowns are discussed. |
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