Kinematics of jaw growth

Growth of the human face occurs in unequal amounts at various areas. This results in relative motion of the upper and lower jaws. Relative motion creates changes in facial appearance and dental occlusion. Orthodontic treatment seeks to therapeutically use or alter this relative motion. Most existing orthodontic analyses have interpreted facial growth as translatory in nature. The analysis introduced in this paper is based on applying kinematic fundamentals—that is, poles of rotation and fixed and moving centrodes—as a tool for more accurately analyzing jaw motion. Reliable data is utilized and computer graphics routines are employed to help visualize output data. Several alternative approaches for analyzing relative motion due to jaw growth are presented here indicating the development of this research.