Belli R, Völkl H, Csato S, Tremmel S, Wartzack S, Lohbauer U (2020)
Publication Language: English
Publication Type: Journal article, Original article
Publication year: 2020
DOI: 10.1016/j.jeurceramsoc.2020.01.064
Here we describe the development of a mechanical test that simulates a circumferential “hoop-stress” at the margins of model dental ceramic crowns. A simplified sphero-cylindrical geometry was modelled in two thicknesses and machined out of two glass-ceramic materials. The specimens were loaded by a conical metallic piston to induce circumferential hoop-stresses at the margins until fracture. Broken specimens were fractographically analyzed to determine the location of the fracture origin and to measure the dimensions of the critical defect, allowing the calculation of the stress at failure from fracture mechanics relations. For thick specimens, machining defects at the outer margins barely played a role in fracture initiation. For thin specimens, outer defects started to dominate the failure mode. CAD/CAM machining showed to predispose thinner margins to early fracture. Crowns should be designed with increased thickness in order to minimize the effect of marginal damage in the circumferential stress field inducing fracture.
APA:
Belli, R., Völkl, H., Csato, S., Tremmel, S., Wartzack, S., & Lohbauer, U. (2020). Development of a hoop-strength test for model sphero-cylindrical dental ceramic crowns: FEA and fractography. Journal of the European Ceramic Society. https://doi.org/10.1016/j.jeurceramsoc.2020.01.064
MLA:
Belli, Renan, et al. "Development of a hoop-strength test for model sphero-cylindrical dental ceramic crowns: FEA and fractography." Journal of the European Ceramic Society (2020).
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