On the in vitro fatigue behavior of human dentin: effect of mean stress.
Human dentin is susceptible to failure under repetitive cyclic-fatigue loading. This investigation seeks to address the paucity of data that reliably quantify this phenomenon. Specifically, the effect of alternating vs. mean stresses, characterized by the stress- or load-ratio R (ratio of minimum-to-maximum stress), was investigated for three R values (-1, 0.1, and 0.5). Dentin was observed to be prone to fatigue failure under cyclic stresses, with susceptibility varying, depending upon the stress level. The "stress-life" (S/N) data obtained are discussed in the context of constant-life diagrams for fatigue failure. The results provide the first fatigue data for human dentin under tension-compression loading and serve to map out safe and unsafe regimes for failure over a wide range of in vitro fatigue lives (< 10(3) to > 10(6) cycles).
Nalla
R K
RK
Materials Sciences Division, Lawrence Berkeley National Laboratory, University of California, Berkeley, CA 94720, USA.
Kinney
J H
JH
Marshall
S J
SJ
Ritchie
R O
RO
D000465:Algorithms; D001696:Biomechanical Phenomena; D003804:Dentin / Q000502:physiology* / Q000648:ultrastructure; D006801:Humans; D008855:Microscopy, Electron, Scanning; D011312:Pressure; D013314:Stress, Mechanical; D014082:Tooth Fractures / Q000473:pathology / Q000503:physiopathology; D016474:Weight-Bearing