Quantitative fractography as a novel approach to measure fracture toughness of direct resin composites. (September 2020)

• Record Type: Journal Article
• Authors: Abdulhameed, Nader; Angus, Brendan; Wanamaker, Jack; Mecholsky, John J.
• Is Part Of: Journal of the mechanical behavior of biomedical materials. Volume 109(2020)
• Publication Date: 2020-09
• Subjects: Fractography -- Dental resin composite -- Fracture toughness -- Elastic modulus; Biomedical materials -- Periodicals; Biomedical materials -- Mechanical properties -- Periodicals; Biomedical materials; Biomedical materials -- Mechanical properties; Periodicals; Electronic journals; 610.28
• DOI: 10.1016/j.jmbbm.2020.103857
• Languages: English
• ISSNs: 1751-6161

Abstract

Abstract: Dental resin composites generally fail from small cracks. Large crack techniques are not representative of in vivo failures. Quantitative fractography relies on the observation of small "natural flaws". This study investigates the effect of flaws that occur from fabrication and handling on the measurement of fracture toughness for four different direct resin composites. Microtensile dog-bone shaped specimens for each of four composites were fractured to measure the strength. In addition, we measured crack sizes of the fracture initiating cracks and determined the fracture toughness from these measurements using quantitative fractographic analysis on selected specimens. The characteristic strengths (28–51 MPa) and Weibull moduli (4.9–7.8) were also determined and related to the toughness values (0.5–0.9 MPa m 1/2 ) obtained. The elastic moduli (5–10 GPa) were measured using an indentation technique that has not been used before for direct resin composites. The indentation technique offers an alternative method for small specimens. Quantitative fractographic analysis offers a useful technique to assess fracture toughness of resin composites from cracks of the same size as observed in practice. The toughness of the direct resin composites results from a balance between the size, number and shape of filler particles and the viscosity of the resin matrix.