Posttreatment changes of skeletal morphology following treatment aimed at restriction of maxillary growth

In the evaluation of the success of orthodontic treatment, an analysis of posttreatment changes was essential. Twenty-eight patients with increased overjet and overbite, a high mandibular plane angle, and perioral dysfunction had been treated by means of normal maximal restriction of maxillary development. The posttreatment changes of the skeletal morphology was analyzed and related to both pretreatment morphology and treatment-produced changes. The correlation analysis demonstrated that less than 25% of the variation in posttreatment changes could be accounted for by pretreatment morphology. However, the dependency of posttreatment changes on treatment-produced changes was stronger with regard to both linear and angular measurements. Upon analyzing the changes in mandibular prognathism during and after treatment, all combinations of downward and forward growth were presented. In some cases the increase in prognathism during treatment would continue after treatment; in others the reverse was true. Opening of the Y axis would in some cases be constant, leading to a decrease in mandibular prognathism. In others a pronounced anterior rotation moved the pogonion forward following treatment. A dental relapse as a consequence of skeletal relapse was seen only in cases in which normal perioral function, including normal lip closure and absence of tongue-thrust swallowing, had not been established.