Journal of Dental Research, Vol 67, 919-924, Copyright © 1988 by International & American Associations for Dental Research Online Journals
Fracture mechanics parameters for failure prediction of composite resins
R. De Groot, H. C. Van Elst and M. C. Peters
Department of Cardiology and Endodontology, School of Dentistry, University of Nijmegen, The Netherlands.
This study contains the first part of a research project in which the
applicability of fracture mechanics parameters to predict failure of a
restored tooth was investigated. Fracture mechanics parameters have been
used in dental research before, but were restricted to comparative studies
between various brands of composites. The critical values of the opening
mode stress intensity factor (KI), its equivalents, the strain energy
release rate (GI), and the J integral (JI), were measured with single-edge
notched-bend (SENB) specimens of dental composite in a three-point bend
test. The measured values of KIc for Silux (KIc = 0.99 +/- 0.03 MNm-3/2)
and P-30 (KIc = 1.88 +/- 0.12 MNm-3/2), compared with values from the
literature, show quantitative agreement. The J integral was computed by
means of finite element analysis (FEA) on a two-dimensional model of the
SENB specimens. The critical value of the J integral (measured with SENB
specimens, notch depth-to-width ratio (a/W) = 1/2) was used to predict
failure of specimens having an arbitrary geometry. In this study, failure
was predicted for SENB specimens with notch depth-to-width ratio (a/W) =
1/4 and 3/4. The predicted deflection and load at failure correspond well
with the measured deflection and load.
