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Fracture Toughness (KIC) of a Dental Porcelain Determined by Fractographic Analysis



Susanne Scherrer, J R. Kelly, George D. Quinn, K Xu


Fractographic analysis of indentation cracks is performed following flexure testing as part of the ASTM (1997) standard for fracture toughness, KIc, determination in advanced ceramics. The purpose of this study was to evaluate the use of fractography in fracture toughness methods with a feldspathic dental porcelain, in which KIc was measured fractographically as well as numerically using two controlled-flaw beam bending techniques. No significant differences were found between numeric and fractographic KIc values for the IS technique at both indentation loads (9.8N and 19.6N) in ambient air, although KIc values were sensitive to indentation load. Stable crack extension was observed fractographically in all IS specimens, as differences between initial (ainitial) and critical (acritical) crack dimensions. For the SCF method, there was a significant difference in toughness between specimens tested in air versus dry nitrogen, however no fractographic evidence for chemically-assisted slow crack growth (SCG) was observed.
Dental Materials Congress
No. 5


ceramics, dental ceramics, fractography, fracture toughness, indentation


Scherrer, S. , Kelly, J. , Quinn, G. and Xu, K. (1999), Fracture Toughness (K<sub>IC</sub>) of a Dental Porcelain Determined by Fractographic Analysis, Dental Materials Congress (Accessed February 24, 2024)
Created August 31, 1999, Updated October 12, 2021