Microfracture behaviour of composite resins containing irregular-shaped fillers.

Microfracture behaviour of composite resins containing irregular-shaped fillers was understood by filler morphology observation, fracture toughness test and acoustic emission (AE) detecting method. The fracture toughness (KIC) was obtained by using single edge notched specimens. AE, the elastic wave due to the debonding of filler from the resin matrix or the fracture of filler itself, was detected during fracture toughness test. The reasons for the different fracture toughness values of composite resin, in spite of having almost the same morphology and filler content, were understood by the results of fracture surface finding and AE releasing behaviour during fracture toughness test.