Brief communication: Correlation between elastic modulus and radiographic density in mandibular cortical bone of colobine monkeys

Abstract

Our results suggest a single exponent can effectively capture the relationship of grayscale to elastic modulus and facilitate development of heterogeneous structural models for use in comparative and computational biomechanical studies.

Biomechanical implications of cortical elastic properties of the macaque mandible

“…Our results show significant regional variations in elastic properties of the macaque mandible as has been found in the mandibles of other mammals (Dechow et al, 1992(Dechow et al, , 1993Dechow, 2002, 2003;Rapoff et al, 2008Rapoff et al, , 2017Daegling et al, 2009Daegling et al, , 2011aDaegling et al, ,b, 2014Daegling et al, , 2015Wang et al, 2010;Zapata et al, 2010;Lad et al, 2016;Le et al, 2016;Dechow, 2017). Of the parameters studied, cortical thickness, density, elastic moduli, shear moduli, and anisotropy exhibited distinct properties within and among regions.…”

“…Baboons, on the other hand, have a significantly lower density anteriorly in the mandible in the symphyseal and canine-P3 regions. Even though density is correlated with bone stiffness (Helgason et al, 2008;Rapoff et al, 2017) in general, this research and related articles previously cited show that this relationship can be highly variable when the differences in elastic properties by direction are considered. For example, comparisons of E2 (minimum stiffness in the cortical plane) (Fig.…”

“…This is evident from ultrasonic three-dimensional studies of elastic properties of cortical bone in mandibles of various species including humans (Dechow et al, 1993;Dechow, 2002b, 2003;Dechow, 2017), baboons (Wang et al, 2010), alligators (Zapata et al, 2010, and pigs (Dechow, 2017). Microindentation techniques that have also been used to determine elastic moduli of cortical bone from mandibles of several Old World and New World monkey species have demonstrated heterogeneity on a micro scale (; Rapoff et al, 2008Rapoff et al, , 2017Daegling et al, 2009Daegling et al, , 2011aDaegling et al, ,b, 2014Daegling et al, , 2015Lad et al, 2016;Le et al, 2016). Overall, studies of elastic properties suggest that variations in the different anatomical regions correspond to morphofunctional partitions and can show similarities between species with close phylogenetic relationships.…”