Barbizam J V B, White S N
School of Dentistry, University of California, Los Angeles, CA, USA.
Int Endod J. 2014 Feb;47(2):202-9. doi: 10.1111/iej.12135. Epub 2013 May 25.
To evaluate effects of ageing and fatigue on the elastic modulus and short-beam shear strength of a quartz fibre/epoxy resin post material.
Cylindrical specimens (25 × 2.2 mm) were made. Elastic moduli were dynamically measured before immersion in water; after immersion in water; periodically during storage in water for up to 7 years; periodically during thermal cycling in water for up to 10 000 cycles to produce thermo-mechanical fatigue; and periodically during boiling in water for up to 100 h. After ageing, the specimens underwent short-beam shear strength testing.
Elastic modulus was significantly decreased by thermal cycling and by immersion in boiling water, but not by water storage. Short-beam shear strength was profoundly decreased by all three ageing processes. Short-beam shear strength was much more sensitive than elastic modulus to the ageing or fatigue processes applied in this study.
A representative endodontic fibre post material was susceptible to a variety of ageing and fatigue processes. The effects of ageing and fatigue had a more pronounced impact on short-beam shear strength than on elastic modulus. The effects of boiling in water and thermal cycling in water were considerably larger than those of simple storage in water.
