Functional significance of cortical bone distribution in anthropoid mandibles

An in vitro assessment of bone strain under combined loads

Datos Bibliográficos

ID8313435
AutoresDavid J Daegling (0000-0002-0108-8986, University of Florida, autor de correspondencia), Jennifer L Hotzman (University of Florida)
Año2003
Volumen122
Número1
Páginas38-50
Fecha de publicación2003-09-01
Peer ReviewedSí
Open AccessSí
TipoARTICLE
RevistaAmerican Journal of Physical Anthropology (JOURNAL)
Identificadores de la revistaISSN: 0002-9483 • E-ISSN: 1096-8644
EditorialWiley (PUBLISHER • GB)
DOI10.1002/ajpa.10225
PMID12923903
OpenAlexW2050446734
IdiomaEN
Citas recibidas17
Referencias citadas39

Local variation in cortical bone thickness in the postcanine mandibular corpus appears to be stereotypical among anthropoids. Specifically, at sections under the molars, lingually situated cortical bone is typically thinner than that along the lateral aspect. This pattern applies despite phylogenetic, dietary, and allometric differences among the anthropoids sampled to date. Demes et al. (Food Acquisition and Processing in Primates [ 1984 ] New York: Plenum Press, p. 369–390) employed a theoretical analysis of mastication in Gorilla and Homo to argue that this pattern could be explained with reference to biomechanical stresses. Specifically, they proposed that the combined effects of torsion and direct shear on the working‐side corpus create a condition in which net stresses and strains are reduced along the lingual cortical plate. Demonstration of this effect would suggest a functional linkage between localized differences in bone mass and strain gradients in the facial skeleton. We conducted an empirical evaluation of the effects of the combined loads of torsion and direct shear in vitro on a sample of formalin‐fixed human mandibles. Rosette strain gages were affixed to the lateral and medial aspects of the corpus in each specimen, and surface strains were recorded separately under controlled torsional and occlusal loads, and under simultaneous application of these loads. The hypothesis that lingual strains are reduced under combined twisting and occlusal loads was generally supported; however, we observed reduction in surface strains at some sites along the lateral aspect of the corpus under these combined loads as well. These unexpected findings are attributable to unanticipated loading conditions imposed by occlusal forces, which result from sources of stress in addition to direct shear. These experiments provide provisional support for the hypothesis that superposed sources of bone strain produce large strain gradients between buccal and lingual aspects of the mandibular corpus, and that local variation in bone mass may be associated with these gradients. Am J Phys Anthropol, 2003. © 2003 Wiley‐Liss, Inc

Allometry · Biology · Composite material · Cortical bone · Mastication · Molar · Primate · Shear stress · Strain (injury) · Torsion (gastropod) · Anatomy · Materials Science · Neuroscience · Orthodontics and Dentofacial Orthopedics · Pleistocene-Era Hominins and Archaeology · Primate Behavior and Ecology