Mandibular movement in lateral excursions

Mandibular movement during lateral articulatory movements was studied in young subjects with no apparent dental disease or malocclusion. A closed circuit television movement detector was used. Signals of each vector of movement were combined in pairs to provide envelopes of movement in three planes, mutually at right angles. Symmetry of movement was not as common as expected and sudden small changes in direction were frequently observed. Maximum displacement in each vector of movement was not always coincident. It is postulated that treatment factors, such as simple restoration of teeth, are initiating factors which cause variation in mandibular movement from the normal.