Supplementary material from "Functional adaptation of the infant craniofacial system to mechanical loadings arising from masticatory forces"

The morphology and biomechanics of infant crania undergo significant changes between the pre- and post- weaning phases due to increasing loading of the masticatory system. The aims of this study were to characterise the changes in muscle forces, bite forces and the pattern of mechanical strain and stress arising from the aforementioned forces across crania in the first 48 months of life using imaging and finite element method. A total of 51 head computed-tomography scans of normal individuals were collected and analysed from a larger database of 217 individuals. The estimated mean muscle forces of temporalis, masseter and medial pterygoid increase from 30.9 to 87.0 N, 25.6 to 69.6 N and 23.1 to 58.9 N respectively (0–48 months). Maximum bite force increases from 90.5 to 184.2 N (3–48 months). And there is a change in the pattern of strain and stress from the calvaria to the face during the postnatal development. Overall, this study highlights the changes in the mechanics of craniofacial system during the normal development. It further raises questions as per how and what level of changes in the mechanical forces during the development can alter the morphology of the craniofacial system.