Incessant Change of Mandibular Growth in Untreated Subjects with Class Ⅲ Malocclusion

摘要

The purpose of this study was to investigate incessant changes of mandibular growth in subjects with growing Class Ⅲ children using strain tensor analysis (STA). The mandibular landmarks of initial and final cephalographs of 40 Taiwanese children with untreated Class Ⅲ malocclusion were defined and digitized. F test evidenced statistical difference (p<0.01) between two stages of mandibular growth. The morphometric assessment of STA was used to obtain a growing tendency of mandibular protrusion. The size change revealed that maximum increase in size of approximately 11.8% was detected between B and Pg. For shape change, the location of major difference was mainly in the incisor alveolus region approximately 8.6%. Furthermore, the size and shape change of the STA is powerful to investigate the incessant growth change of the Class Ⅲ mandible.