Effects of facial mask treatment are attributed to accelerated maxillary growth and inhibited counter-clockwise total rotation of the mandibular corpus: A structural superimposition study

Abstract Purpose To test the hypothesis that facial mask treatment influences maxillary sutural growth, condylar growth, and total rotation of mandibular corpus, using a structural superimposition analysis by Bjork et al. Materials and methods Subjects consisted of 28 girls with Angle Class III malocclusion treated with facial mask (FM group). Eleven girls with pseudo-Class III malocclusion (pseudo-III group) were also examined. Pre- and posttreatment lateral cephalograms were analyzed to evaluate skeletal changes. Cephalometric structural superimposition analysis was also performed. Results The FM group exhibited significantly larger forward maxillary growth and negative total rotation of the mandibular corpus as compared to the pseudo-III group. In the FM group, forward maxillary skeletal growth correlated significantly with maxillary counter-clockwise rotation. Negative mandibular total rotation correlated significantly with inhibition of the forward position of the mandible. Conclusion Accelerated maxillary sutural growth and inhibited counter-clockwise total rotation of mandibular corpus growth attributed to facial mask treatment may contribute to improvements in Class III malocclusion. The greater the acceleration of maxillary sutural growth due to facial mask treatment, the greater the increase in maxillary counter-clockwise rotation.