Fatigue of human dentin by cyclic loading and during oral biofilm challenge.
Fatigue caused by the cyclic loads of mastication and acid attack caused by the excretion of oral biofilms are two of the most critical challenges to the success of dental restorations and their clinical service life. The objective of this investigation was to evaluate the fatigue strength of human dentin when exposed to a simultaneous challenge of cyclic loading and acidic attack from oral bacteria. Rectangular beams of coronal dentin were obtained from third molars and subjected to cyclic flexural loading while exposed to an in-vitro microcosm biofilm model. Two different cariogenic protocols were considered and results were compared with those for control samples evaluated at neutral pH. According to the fatigue life distributions, dentin exposed to the biofilm model with 2.0% sucrose supplements pulsed twice per day caused a significant reduction in the fatigue strength (p < 0.001) with respect to 0.2% sucrose supplements pulsed once a day, and the control environment (without biofilm). The endurance limit after biofilm exposure was 20 MPa, which is 60% lower than that of the control environment without biofilm (50 MPa). Biofilm attack of dentin increases the likelihood of restored tooth failures by fatigue and after only modest periods of exposure. © 2016 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 105B: 1978-1985, 2017.
Department of Mechanical Engineering, University of Maryland Baltimore County, Baltimore, Maryland.
Santiago
S
Orrego
Department of Endodontics, Prosthodontics, and Operative Dentistry, Dental School, University of Maryland Baltimore, Baltimore, Maryland.
Mary Anne
MA
Melo
Division of Mechanical Engineering, Kyungnam University, Changwon, 631-701, Korea.
Se-Han
SH
Lee
Department of Endodontics, Prosthodontics, and Operative Dentistry, Dental School, University of Maryland Baltimore, Baltimore, Maryland.
Hockin H K
HHK
Xu
Department of Materials Science and Engineering, University of Washington, Seattle, Washington, DC.|Department of Restorative Dentistry, School of Dentistry, University of Washington, Seattle, Washington, DC.
Dwayne D
DD
Arola
D000293:Adolescent; D000328:Adult; D018441:Biofilms / Q000254:growth & development*; D003731:Dental Caries; D003804:Dentin / Q000737:chemistry* / Q000382:microbiology; D005260:Female; D006801:Humans; D006863:Hydrogen-Ion Concentration; D008297:Male; D013314:Stress, Mechanical
demineralization; dentin; fatigue; oral biofilm; restoration