A comparative study of pre- and post-treatment cephalometric measurements : extraction vs. non-extraction groups of Class I malocclusion

Yu, Hyung Seog; Baik, Hyoung Seon

Abstract

71 Class I maloccousion samples were selscted and they were divided into premolar-extraction and non-extraction groups. Vertical and horizontal cephalometric evaluations on dental and soft tissue measurements were done before and after treatment. Also, treatment results in adolescent patients and adult patients were compared. The following conclusions were obrained: 1. In comparison of extraction and non-extraction groups, all the dental and soft tissue measurements, with exception of SN-MP angle, upper lip to E-line, vertical movement of upper first molar, and horizintal movement of lower first molar, showed statistically significant differences. 2. In comparison of extraction and non-extraction groups of adolescent samples, there were statistically significant differences in upper and lower incisor inclinations, horizontal dental movements from vertical reference line, positional changes in upper and lower lips, and mesial movements of upper first molar. 3. In comparison of extraction and non-extraction groups of adult samples, there were statistically sigmificant differences in upper and lower incisor inclinations, horizintal dental movements from vertical reference line, positional changes in upper and lower lips from E-line and vertical reference line, vertical hright of upper first molar, and mesial morement of lower first molar. 4. There was no statistically significant difference in SN-MP angle between extraction and non-extraction groups od both adolescent and adult samples.