Motion characteristics of the human TMJ during border movements: a preliminary study

Purpose. Unambiguous evidence of pure rotation of a mandible put in CR position has never been provided in living subjects. The hypothesis of this investigation was that there are no significant differences, owing to the intervention of different operators, between acquisitions. The aim of this work was to validate our acquisition protocol to quantify the contribution of different operators to the CR movements. Methods. Five male adults volunteered for this study. Mandibular movements of open-close, laterotrusion and protrusion were recorded via an optoelectronic device. Four acquisitions for each subject were made from an operator induced CR starting position, another four from ICP. Two different operators put the subjects in CR. For each subject, the mandibular motions were cleaned from external movements, the motions of the interincisor point were reconstructed and the rotational component was calculated in particular in the instants of maxima. Results. For every considered movement, the influence of the operator in putting each subject in CR was negligible. Between CR and ICP movements no significant. differences in the points of maxima were found regarding the percentage contribution of rotation, this contribution in CR movements was never exhaustive. Clinical significance. The protocol for the detection of mandibular movements may be considered repeatable and thus be used to perform deeper analysis on the considered movements in an attempt to find a scientific basis to the use of CR mounted models.