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.

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



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


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.
Journal of Biomedical Materials Research Part B-Applied Biomaterials


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


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], (Accessed April 16, 2024)
Created October 24, 2006, Updated February 19, 2017