American journal of orthodontics and dentofacial orthopedics : official publication of the American Association of Orthodontists, its constituent societies, and the American Board of Orthodontics
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Am J Orthod Dentofacial Orthop · Sep 1994
A study of patient facial expressivity in relation to orthodontic/surgical treatment.
A dynamic analysis of the faces of patients seeking an aesthetic restoration of facial aberrations with orthognathic treatment requires (besides the routine static study, such as records, study models, photographs, and cephalometric tracings) the study of their facial expressions. To determine a classification method for the units of expressive facial behavior, the mobility of the face is studied with the aid of the facial action coding system (FACS) created by Ekman and Friesen. With video recordings of faces and photographic images taken from the video recordings, the authors have modified a technique of facial analysis structured on the visual observation of the anatomic basis of movement. ⋯ It was possible to distinguish changes in facial expressivity in patients after dentofacial surgery, the type and degree of change depended on the facial structure before surgery. Changes noted tended toward a functioning that is identical to that of subjects who do not suffer from dysmorphosis and toward greater lip competence, particularly the function of the orbicular muscle of the lips, with reduced compensatory activity of the lower lip and the chin. The results of our study are supported by the clinical observations and suggest that the FACS technique should be able to provide a coding for the study of facial expression.