title: Importance of age on the dynamic mechanical behavior of intertubular and peritubular dentin.
abstract: An experimental evaluation of human coronal dentin was performed using nanoscopic dynamic mechanical analysis (nanoDMA). The primary objectives were to quantify any unique changes in mechanical behavior of intertubular and peritubular dentin with age, and to evaluate the microstructure and mechanical behavior of the mineral deposited within the lumens. Specimens of coronal dentin were evaluated by nanoDMA using single indents and in scanning mode via scanning probe microscopy. Results showed that there were no significant differences in the storage modulus or complex modulus between the two age groups (18-25 versus 54-83 yrs) for either the intertubular or peritubular tissue. However, there were significant differences in the dampening behavior between the young and old dentin, as represented in the loss modulus and tanδ responses. For both the intertubular and peritubular components, the capacity for dampening was significantly lower in the old group. Scanning based nanoDMA showed that the tubules of old dentin exhibit a gradient in elastic behavior, with decrease in elastic modulus from the cuff to the center of tubules filled with newly deposited mineral.
authors.affiliation: Department of Mechanical Engineering, University of Maryland Baltimore County, Baltimore, MD, USA.
authors.forename: Heonjune
authors.initials: H
authors.lastname: Ryou
authors.affiliation: Department of Endodontics, Prosthodontics and Operative Dentistry, Dental School, University of Maryland, Baltimore, MD, USA.
authors.forename: Elaine
authors.initials: E
authors.lastname: Romberg
authors.affiliation: Department of Oral Biology, College of Dental Medicine, Georgia Health Sciences University, Augusta, GA, USA.
authors.forename: David H
authors.initials: DH
authors.lastname: Pashley
authors.affiliation: Department of Oral Biology, College of Dental Medicine, Georgia Health Sciences University, Augusta, GA, USA; Department of Endodontics, College of Dental Medicine, Georgia Health Sciences University, Augusta, GA, USA.
authors.forename: Franklin R
authors.initials: FR
authors.lastname: Tay
authors.affiliation: Department of Materials Science and Engineering, University of Washington Seattle, WA, USA; Department of Restorative Dentistry, School of Dentistry, University of Washington, Seattle, WA, USA. Electronic address: darola@u.washington.edu.
authors.forename: Dwayne
authors.initials: D
authors.lastname: Arola
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000375:Aging; D001696:Biomechanical Phenomena; D003804:Dentin / Q000502:physiology*; D005260:Female; D006244:Hardness; D006801:Humans; D008297:Male; D008422:Materials Testing; D055595:Mechanical Phenomena; D008875:Middle Aged; D036103:Nanotechnology; D055815:Young Adult
keywords: Aging; Dentin; Dynamic mechanical analysis (DMA); Elastic modulus; Nanoindentation