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Work of fracture of a composite resin: Fracture‐toughening mechanisms
Author(s) -
Baudin Carmen,
Osorio Raquel,
Toledano Manuel,
de Aza Salvador
Publication year - 2008
Publication title -
journal of biomedical materials research part a
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.849
H-Index - 150
eISSN - 1552-4965
pISSN - 1549-3296
DOI - 10.1002/jbm.a.32016
Subject(s) - materials science , composite material , weibull modulus , modulus , stress intensity factor , composite number , fracture (geology) , fracture toughness , weibull distribution , fracture mechanics , flexural strength , statistics , mathematics
The aim of this work was to investigate those mechanical parameters able to describe the fracture behavior of dental composite resins. A commercially available fine‐particle micro‐hybrid resin composite was used. Classical parameters as Young's modulus, strength distribution, and critical stress intensity factor were considered. Strength values were determined using the diametrical compression of discs test and for the critical stress intensity factor both unstable and controlled fracture tests were used. Controlled fracture tests allowed determining the work of fracture. Microstructure was studied by optical and field emission scanning electron microscopy. The obtained properties have been Young's modulus, 17.7 ± 0.6 GPa; Weibull modulus, m = 14 (upper and lower limits for 90% confidence: 17 and 10); characteristic strength 51 MPa (upper and lower limits for 90% confidence: 53 and 49 MPa); critical stress intensity factor in mode I, K IC = 1.3 ± 0.1 and work of fracture, γ wof = 8–9 J/m 2 . Pores and bubbles formed during the packing of the composite were identified as critical defects in the tested specimens. Crack deflection and branching have been identified as toughening mechanisms. Classical mechanical parameters (Young's modulus, hardness…) are not able to efficiently predict the major clinical failure mode of composite resins by fatigue. Work of fracture analysis, which is dependant on microstructural parameters such as particle size and shape, have to be included when testing mechanical properties of dental composite resins in future research studies. © 2008 Wiley Periodicals, Inc. J Biomed Mater Res, 2009