Biomaterial Database

Effect of Griffith precracks on measurement of composite fracture toughness. 1993

R E Kovarik, and C W Fairhurst

Department of Oral Health Practice, University of Kentucky College of Dentistry, Lexington.

The objective of this study was to produce true Griffith-type cracks in composite specimens for measuring fracture toughness. A compact test specimen geometry, conforming to the ASTM standard (E-399-84) was chosen for the evaluation. Five methods of precracking were evaluated: 1) placing no precrack (notch in specimen left blunt); 2) placing a sharp notch with a Bard Parker blade under hand pressure; 3) placing a sharp notch with a Bard Parker blade under hand pressure, followed by stressing the sample at 60% of the failure load for 25 cycles; 4) forming a sharp notch by placing a razor blade in the sample during polymerization; and 5) placing a Griffith-type crack. Results indicate that the method of precracking a sample does have a significant effect on the measured value of the fracture toughness.

UI	MeSH Term	Description	Entries
D008422	Materials Testing	The testing of materials and devices, especially those used for PROSTHESES AND IMPLANTS; SUTURES; TISSUE ADHESIVES; etc., for hardness, strength, durability, safety, efficacy, and biocompatibility.	Biocompatibility Testing,Biocompatible Materials Testing,Hemocompatibility Testing,Testing, Biocompatible Materials,Testing, Hemocompatible Materials,Hemocompatibility Testings,Hemocompatible Materials Testing,Materials Testing, Biocompatible,Materials Testing, Hemocompatible,Testing, Biocompatibility,Testing, Hemocompatibility,Testing, Materials,Testings, Biocompatibility
D003188	Composite Resins	Synthetic resins, containing an inert filler, that are widely used in dentistry.	Composite Resin,Resin, Composite,Resins, Composite
D003799	Dental Stress Analysis	The description and measurement of the various factors that produce physical stress upon dental restorations, prostheses, or appliances, materials associated with them, or the natural oral structures.	Analyses, Dental Stress,Analysis, Dental Stress,Stress Analyses, Dental,Stress Analysis, Dental,Dental Stress Analyses
D006244	Hardness	The mechanical property of material that determines its resistance to force. HARDNESS TESTS measure this property.	Hardnesses
D000704	Analysis of Variance	A statistical technique that isolates and assesses the contributions of categorical independent variables to variation in the mean of a continuous dependent variable.	ANOVA,Analysis, Variance,Variance Analysis,Analyses, Variance,Variance Analyses
D014520	Urethane	Antineoplastic agent that is also used as a veterinary anesthetic. It has also been used as an intermediate in organic synthesis. Urethane is suspected to be a carcinogen.	Ethyl Carbamate,Urethan,Carbamate, Ethyl