Development of predictive models of occlusal loading of the facial skeleton
will be of value for prosthetic design in oral rehabilitation. A 3-D finit
e element (FE) model of a human skull, based on CT scans, was constructed t
o analyse strain and stress distribution in the facial skeleton caused by s
imulated occlusal loading. Vertical loads were applied simulating loading o
f the full maxillary arch and unilateral single point occlusal loading of m
axillary molar, pre-molar, canine and incisor sites. Strain and stress regi
mes from Von Mises (VM) failure criteria and extension and compression diag
rams showed even distribution of strain following loading of the full maxil
lary arch throughout the facial elements. For individual points, the highes
t VM concentrations were consistently located on the facial aspect several
mm above the loading site. Strain trajectories divided into a 'V-shaped' pa
ttern, from the loading point into medial and lateral branches with higher
VM values in the medial. As the same load was applied from the posterior to
anterior region, VM values increased on all facial areas. Strain patterns
were less symmetric and there was an increase in strain in the alveolar arc
h and around the rim of the nasal cavity. The overall picture of the facial
skeleton is of a vertical plate enabling it to withstand occlusal stresses
by in-plane loading and bending in its own plane. The most efficient distr
ibution of load was on maxillary full arch loading with the most unfavourab
le strain concentrations occurring on loading in the anterior region.