RESUMO
Questions exist concerning the degree to which orthodontic treatment alters facial form. This study has attempted to discern changes in several measures of vertical facial form which might be influenced by varying vectors and amounts of extraoral force. The data were collected from pre- and posttreatment lateral cephalograms of 200 children treated consecutively with full edgewise orthodontic appliances. The sample was divided into three pretreatment groups based on the type of extraoral force delivered; cervical, "combi," and no-headgear. All groups showed a wide range of variation in treatment response, but did not demonstrate significant differences. While the extraoral forces predictably improved horizontal maxillo-mandibular discrepancies, there was too much variation in response to predict vertical changes.
