Regional variation of bone tissue properties at the human mandibular condyle.
The temporomandibular joint (TMJ) bears different types of static and dynamic loading during occlusion and mastication. As such, characteristics of mandibular condylar bone tissue play an important role in determining the mechanical stability of the TMJ under the macro-level loading. Thus, the objective of this study was to examine regional variation of the elastic, plastic, and viscoelastic mechanical properties of human mandibular condylar bone tissue using nanoindentation. Cortical and trabecular bone were dissected from mandibular condyles of human cadavers (9 males, 54-96 years). These specimens were scanned using microcomputed tomography to obtain bone tissue mineral distribution. Then, nanoindentation was conducted on the surface of the same specimens in hydration. Plastic hardness (H) at a peak load, viscoelastic creep (Creep/Pmax), viscosity (η), and tangent delta (tan δ) during a 30 second hold period, and elastic modulus (E) during unloading were obtained by a cycle of indentation at the same site of bone tissue. The tissue mineral and nanoindentation parameters were analyzed for the periosteal and endosteal cortex, and trabecular bone regions of the mandibular condyle. The more mineralized periosteal cortex had higher mean values of elastic modulus, plastic hardness, and viscosity but lower viscoelastic creep and tan δ than the less mineralized trabecular bone of the mandibular condyle. These characteristics of bone tissue suggest that the periosteal cortex tissue may have more effective properties to resist elastic, plastic, and viscoelastic deformation under static loading, and the trabecular bone tissue to absorb and dissipate time-dependent viscoelastic loading energy at the TMJ during static occlusion and dynamic mastication.
Division of Orthodontics, College of Dentistry, The Ohio State University, Columbus, OH 43210, USA. Electronic address: kim.2508@osu.edu.
Do-Gyoon
DG
Kim
Division of Orthodontics, College of Dentistry, The Ohio State University, Columbus, OH 43210, USA.
Yong-Hoon
YH
Jeong
Division of Orthodontics, College of Dentistry, The Ohio State University, Columbus, OH 43210, USA.
Erin
E
Kosel
Division of Anatomy, College of Medicine, The Ohio State University, Columbus, OH 43210, USA.
Amanda M
AM
Agnew
Department of Materials Science and Engineering, College of Engineering, The Ohio State University, Columbus, OH 43210, USA.
David W
DW
McComb
Department of Biomedical Engineering, College of Engineering, The Ohio State University, Columbus, OH 43210, USA.
Kyle
K
Bodnyk
Department of Biomedical Engineering, College of Engineering, The Ohio State University, Columbus, OH 43210, USA.
Richard T
RT
Hart
Division of Orthodontics, College of Dentistry, The Ohio State University, Columbus, OH 43210, USA.
Min Kyung
MK
Kim
Division of Orthodontics, College of Dentistry, The Ohio State University, Columbus, OH 43210, USA.
Sang Yeun
SY
Han
Division of General Practice and Materials Science, College of Dentistry, The Ohio State University, Columbus, OH 43210, USA.
William M
WM
Johnston
D000368:Aged; D000369:Aged, 80 and over; D002102:Cadaver; D006801:Humans; D008297:Male; D008335:Mandibular Condyle / Q000033:anatomy & histology*; D008875:Middle Aged; D055114:X-Ray Microtomography
Human mandibular condyle; Nanoindentation; Regional variation; Temporomandibular joint; Viscoelastic