Role of Indenter Material and Size in Veneer Failure of Brittle Layer Structures

Published

October 24, 2006

Author(s)

Sanjit Bhowmick, Juan J. Melendez-Martinez, Ilja Hermann, Yu Zhang, Brian R. Lawn

Abstract

The roles of indenter material and size in the failure of brittle veneer layers in all-ceramic crown-like structures are studied. Glass veneer layers 1 mm thick bonded to alumina layers 0.5 mm thick on polycarbonate bases (representative of porcelain/ceramic core/dentin) are subject to cyclic contact loading with spherical indenters in water (representative of occlusal biting environment). Two indenter materials glass and tungsten carbide and three indenter radii 1.6 mm, 5.0 mm and 12.5 mm are investigated in the tests. A video camera is used to follow the near-contact initiation and subsequent downward propagation of cone cracks through the veneer layer to the core interface, at which point the specimen is considered to have failed. Both indenter material and indenter radius have some effect on the critical loads to initiate cracks within the local Hertzian contact field, but the influence of modulus is weaker. The critical loads to take the veneer to failure are relatively insensitive to either of these indenter variables, since the bulk of the cone crack propagation takes place in the contact far field. Clinical implications of the results are considered, including the issue of single-cycle overload versus low-load cyclic fatigue and changes in fracture mode with loading conditions.

Citation

Journal of Biomedical Materials Research Part B-Applied Biomaterials

Volume

82B

Pub Type

Journals

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Keywords

cone cracks, cyclic fatigue, dental crowns, indenter material, indenter size

Citation

Bhowmick, S. , Melendez-Martinez, J. , Hermann, I. , Zhang, Y. and Lawn, B. (2006), Role of Indenter Material and Size in Veneer Failure of Brittle Layer Structures, Journal of Biomedical Materials Research Part B-Applied Biomaterials, [online], https://tsapps.nist.gov/publication/get_pdf.cfm?pub_id=850145 (Accessed October 3, 2024)