Three-dimensional evaluation of changes in lip position from before to after orthodontic appliance removal

IntroductionOur objectives were to develop a reproducible method of superimposing 3-dimensional images for measuring soft-tissue changes over time and to use this method to document changes in lip position after the removal of orthodontic appliances.MethodsThree-dimensional photographs of 50 subjects were made in repose and maximum intercuspation before and after orthodontic appliance removal with a stereo camera. For reliability assessment, 2 photographs were repeated for 15 patients. The images were registered on stable areas, and surface-to-surface measurements were made for defined landmarks.ResultsMean changes were below the level of clinical significance (set at 1.5 mm). However, 51% and 18% of the subjects experienced changes greater than 1.5 mm at the commissures and lower lips, respectively.ConclusionsThe use of serial 3-dimensional photographs is a reliable method of documenting soft-tissue changes. Soft-tissue changes after appliance removal are not clinically significant; however, there is great individual variability.