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

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.