F Takeshige1, Y Kawakami, M Hayashi, S Ebisu. 1. Osaka University Graduate School of Dentistry, Department of Restorative Dentistry and Endodontology, 1-8, Yamadaoka, Suita, Osaka 565-0871, Japan.
Abstract
OBJECTIVES: Interaction between mechanical and chemical fatigue of resin composites was investigated. METHODS: Fatigue fracture resistance of composites after (1) water immersion and under (2) dry and (3) aqueous conditions was analyzed using a fatigue crack propagation test. The characteristics of fatigue crack propagation were expressed as the correlation between the fatigue crack growth rate (da/dN) and stress intensity factor range (DeltaK) and by the fatigue crack growth threshold (DeltaKth). Following the fatigue test, a fractographic examination was performed by scanning electron microscopy. RESULTS: Contrary to common perception, fatigue crack propagation was retarded under aqueous conditions but accelerated after water immersion. In addition, fatigue cracks detoured around inorganic macro-fillers, but penetrated organic fillers. SIGNIFICANCE: It was concluded that the inverse effects of water on fatigue resistance of composites are dependent on the experimental conditions. Moreover, inorganic macro-fillers were shown to be functional in retarding fatigue cracks in composites.
OBJECTIVES: Interaction between mechanical and chemical fatigue of resin composites was investigated. METHODS:Fatigue fracture resistance of composites after (1) water immersion and under (2) dry and (3) aqueous conditions was analyzed using a fatigue crack propagation test. The characteristics of fatigue crack propagation were expressed as the correlation between the fatigue crack growth rate (da/dN) and stress intensity factor range (DeltaK) and by the fatigue crack growth threshold (DeltaKth). Following the fatigue test, a fractographic examination was performed by scanning electron microscopy. RESULTS: Contrary to common perception, fatigue crack propagation was retarded under aqueous conditions but accelerated after water immersion. In addition, fatigue cracks detoured around inorganic macro-fillers, but penetrated organic fillers. SIGNIFICANCE: It was concluded that the inverse effects of water on fatigue resistance of composites are dependent on the experimental conditions. Moreover, inorganic macro-fillers were shown to be functional in retarding fatigue cracks in composites.
Authors: Mustafa Murat Mutluay; Ke Zhang; Heonjune Ryou; Mobin Yahyazadehfar; Hessam Majd; Hockin H K Xu; Dwayne Arola Journal: J Mech Behav Biomed Mater Date: 2012-11-17
Authors: Zihou Zhang; Dylan Beitzel; Mustafa Mutluay; Franklin R Tay; David H Pashley; Dwayne Arola Journal: Dent Mater Date: 2015-07-10 Impact factor: 5.304
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