Variation of hinge interocclusal clearance and modifying mechanisms.

On the basis of Newtonian principles of applied mechanics, rotation around the mandibular hinge axis has been explored by separating this rotation from translation of the mandibular hinge axis. After quantitative comparison, it appears that hinge rotation is the primary physiologic movement of the mandible, and that the Hanau quint provides compensatory factors in facilitating hinge jaw movement. However, an unguided opening and closing of the mouth usually consists of rotation and translation that are six-dimensional in nature and very difficult to solve quantitatively without idealization and differentiation. With an accurate three-dimensional image-measuring system, such as computerized axial tomography, it should be possible to apply this hypothesis clinically.