Stress patterns in conical teeth of reptiles and mammals: experimental and finite element analyses

Abstract

A 3-Dimensional Finite Element Analysis (FEA) of conical teeth of reptiles and some mammals, suggests that under a vertical loading condition along the longer axis of tooth, horizontal tensile stresses are produced. In dental enamel, these stresses are distributed mainly in two horizontal directions, i.e. in X direction and in Z direction. The empirical observation of stresses possibly leading to the vertical failure of the teeth was obtained through Universal Testing Machine (UTM) using recent unicuspid teeth of crocodiles, varanus and canines of pig, cat and dog. The horizontal development of Hunter Schreger Bands (HSBs) has been observed in the enamel of canines of herbivore and carnivore mammals, which seems to be an effective structural strategy to counter splitting of tooth enamel under vertical loading. In contrast, the unicuspid teeth of reptiles lack the HSBs, and are more susceptible to failure. However, as reptilian teeth are continuously replaced, the damage is negligible.