Effectiveness of dental arch expansion: A preliminary study of two customized fixed lingual orthodontic systems
Kurtzner, Brian William
MetadataShow full item record
Background: The integration of modern technology has driven the customization of lingual orthodontic appliances. Orthodontic expansion is among the touted advantages of fully customized lingual orthodontic systems. Purpose: To investigate the effectiveness of the Harmony and Incognito systems, two fully customized lingual orthodontic appliances, to achieve orthodontic expansion, as predetermined through a target setup. Materials and Methods: Arch width measurements were taken from photographs of 28 subjects and scaled using initial casts. Measurements were taken at the cuspids, first bicuspids, second bicuspids, and first molars. Final arch width increase was compared to that planned, as determined by the digital target setup, between the two systems. Additional records for Harmony subjects allowed further analysis of trends in expansion throughout the course of treatment: Initial (T0), insertion (T1) and removal (T2) of 0.016 x 0.022" nickel titanium archwire, insertion (T3) and removal (T4) of 0.018 x 0.025" titanium molybdenum archwire, and final (T5). Results: Harmony subjects achieved a significantly greater percentage of arch width increase, relative to the setup, at each measurement site than Incognito subjects. Further analysis of Harmony subjects revealed that while all subjects experienced an increase in arch width from insertion to removal of a 0.016 x 0.022” nickel titanium wire, the effect of an 0.018 x 0.025” titanium molybdenum wire on arch width was variable. Conclusions: The Harmony system, with an edgewise slot orientation, may result in more effective expansion compared to the Incognito system, with a ribbon-wise slot orientation.