Reproducibility of a method for analysis of morphological changes in perioral soft tissue in children using video...

The purpose of the present study was to determine the appropriate reference facial expression and to examine the reproducibility of our system using two commercially available video cameras in consideration of functional diagnosis of perioral muscles. The following items were investigated: 1) influence of forward and backward movements and the experiment sequence from measurement to analysis, 2) usefulness of head fixation by a restraining device during video recording for evaluation of morphological changes in facial expression, 3) conditions for establishment of reference points for determination of movements of perioral soft tissue, and 4) reproducibility of perioral soft tissue movements as assessed by changes in landmarks. The results of this study showed that accurate static and dynamic evaluation of perioral soft tissue is possible by using our method of video recording with the subject's head restrained and our method of analysis. The results also showed that centric occlusion of the most appropriate reference facial expression as for measurement of perioral soft tissue movements and that protrusion of the lips and lateral extension of the angel of the mouth are facial expressions with high degrees of reproducibility.