Effect on the Occlusal Force Buffering Mechanism of Occluding on Various Sizes of Materials in Monkey Skulls

Abstract

The masseter muscle of anesthetized adult and infant monkeys were electrically stimulated, and occlusion on various sizes of materials simulated by placement of 3, 5, and 7 mm thickness sticks in the molar region on one side.
As the size of the occluding material increased, the occlusal forces were increased, accompanied by increases in the strain arising in the skull. In contrast, when the material was too large, i. e., when the degree of opening was excessive, there was a decrease in strain.
When the size of the occluding material was large, the number of bones where stresses concentrated were greater in adults than in infants. This phenomenon resulted from the fact that the skull in infancy tends to buffer occlusal forces as one unit since the bones are immature, in contrast to the adult skull where each bone can buffer the occlusal forces independently since it is fully developed.
In addition, it was found that the occlusal force buffering effect of the temporal and parietal bones were markedly different in infants and adults.