Influence of preparation of ceramic SEVNB specimens on fracture toughness testing results

Abstract Objectives Fracture toughness KIc is an important mechanical property of dental ceramics. One of the most reliable methods to determine the fracture toughness of a ceramic material is the single-edge V-notched-beam (SEVNB) method. The objective of the study is to reveal and quantify the inf...

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Bibliographic Details
Published in:Dental materials 2008-05, Vol.24 (5), p.618-622
Main Authors: Fischer, H, Waindich, A, Telle, R
Format: Article
Language:English
Subjects:
Advanced Basic Science
Biomechanical Phenomena
Ceramics - chemistry
Critical notch root radius
Dental Materials - chemistry
Dental Porcelain - chemistry
Dentistry
Fracture toughness
Humans
Materials Testing - methods
Materials Testing - standards
Models, Theoretical
Pliability
SEVNB method
Stress, Mechanical
Surface Properties
Yttrium - chemistry
Zirconia
Zirconium - chemistry
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Summary:Abstract Objectives Fracture toughness KIc is an important mechanical property of dental ceramics. One of the most reliable methods to determine the fracture toughness of a ceramic material is the single-edge V-notched-beam (SEVNB) method. The objective of the study is to reveal and quantify the influence of the notch root radius on the fracture toughness value proved on the high strength ceramic material zirconia. Methods Bar specimens ( n = 16) made of high strength zirconia ceramics (3Y-TZP) were notched by a diamond charged cutting wheel. The notch roots were sharpened using the razor blade method with systematically varying notch root radii. The critical stress intensities as a function of the respective notch root radii of all specimens were determined in flexural strength test. Results The notch root radii showed a pronounced effect on the determined fracture toughness values. Notch root radii between 18 and 167 μm were produced. The respective determined fracture toughness values varied between 5.9 and 13.6 MPam0.5. Significance It is of decisive importance to sharpen the notch root radius of a SEVNB specimen to determine the true fracture toughness value. If the notch root radius is above a critical value, the measured fracture toughness value will be overestimated.
ISSN:0109-5641
1879-0097
DOI:10.1016/j.dental.2007.06.021