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Contact damage as a failure mode during in vitro testing.
- Source :
-
Journal of prosthodontics : official journal of the American College of Prosthodontists [J Prosthodont] 1996 Jun; Vol. 5 (2), pp. 95-100. - Publication Year :
- 1996
-
Abstract
- Purpose: The purpose of this study was to identify the failure mode(s) for all-ceramic crowns tested in vitro and to determine whether measured failure loads in this type of testing would be influenced by indenter radii (a classic Hertzian cone-crack variable) and specimen thickness.<br />Materials & Methods: Fracture surfaces and failure probability data from glass-ceramic cuspids (n = 50) tested in a previous in vitro study were examined to determine their mode of failure. To further evaluate the failure mode identified for the crowns, 100 ceramic platelets (50 glass-ceramic, 50 feldspathic porcelain) were loaded to failure beneath spherical indenters (radii, 0.75-94 mm).<br />Results: Glass-ceramic cuspids failed from blunt contact damage at the point of loading (with Hertzian stress-state damage evident). Ceramic platelets exhibited failure from either the indentation surface (Hertzian cone-cracking present) or from the supported surface (ie, mimicking bending failure). Failure-loads increased with the indenter radius for both failure modes. Failure from blunt contact damage occurred at markedly higher loads than did failure from support-surface sites.<br />Conclusions: Blunt indentation damage was identified as being the failure source for the glass-ceramic cuspid crowns and a major failure mode for both feldspathic porcelain and glass-ceramic platelets loaded beneath spherical indenters. This failure mode is not similar to that reported for clinically failed glass-ceramic crowns. Influential testing variables were contact radius, ceramic thickness, and the surface finish of both the ceramic specimen and test platen.
Details
- Language :
- English
- ISSN :
- 1059-941X
- Volume :
- 5
- Issue :
- 2
- Database :
- MEDLINE
- Journal :
- Journal of prosthodontics : official journal of the American College of Prosthodontists
- Publication Type :
- Academic Journal
- Accession number :
- 9028211
- Full Text :
- https://doi.org/10.1111/j.1532-849x.1996.tb00281.x