Changes in the gonial region induced by alterations of muscle length.

Thirty-eight adult rhesus monkeys were used in the study of osseous remodeling of the gonial region following various types of experimental intervention. This study indicated the following: (1) When the length of the masseter muscle is increased by increasing the vertical dimension, resorption in the gonial region takes place. (2) When the original length of the masseter muscle is increased by an appliance and a sham operation is performed, increased resorption, greater than that observed when only an appliance is used, is observed. (3) When a muscle is detached following an increase in vertical dimension and allowed to reattach spontaneously, the largest amount of gonial remodeling is observed. These observations indicate that both blood supply and function influence the shape of the gonial region.