Margin Failures in Brittle Dome Structures: Relevance to Failure of Dental Crowns

Published

October 12, 2021

Author(s)

T Qasim, Chris Ford, M T. Bush, X Z. Hu, Kenneth Malament, Brian R. Lawn

Abstract

Margin cracks in loaded brittle dome structures are investigated. Dome structures consisting of glass shells filled with polymer resin, simulating the essential features of brittle crowns on tooth dentin, provide model test specimens. Disk indenters of diminishing elastic modulus are used to apply axisymmetric loading to the apex of the domes. Previous studies using hard indenters have focused on fractures initiating in the near-contact region of such specimens, including radial cracks at the glass undersurface directly below the contact axis. Here we focus on fractures initiating at the remote support margins. Margin cracks can become dominant when loading forces are distributed over broad contact areas, as in biting on soft matter, here simulated by balsa wood disks. Cracks preinitiated at the dome edges during the specimen preparation propagate under load around the dome side into segmented, semi-lunar configurations reminiscent of some all-ceramic crown failures. Finite element analysis is used to determine the basic stress states within the dome structures, and to confirm a shift in maximum tensile stress from the near-contact area to the dome sides with more compliant indenters.

Citation

Journal of Biomedical Materials Research

Pub Type

Journals

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Keywords

all-ceramic crowns, crown failure, lunar cracks, stress analysis

Citation

Qasim, T. , Ford, C. , Bush, M. , Hu, X. , Malament, K. and Lawn, B. (2021), Margin Failures in Brittle Dome Structures: Relevance to Failure of Dental Crowns, Journal of Biomedical Materials Research, [online], https://tsapps.nist.gov/publication/get_pdf.cfm?pub_id=850137 (Accessed January 14, 2025)