A comparative study of vertical lip changes after standard edgewise and preadjusted orthodontic treatments

Abstract

Context: Frontal esthetics should equal the profile in importance when planning orthodontic treatment. Soft tissue profile changes associated with orthodontic treatment have been the subject of many studies, but changes in the vertical dimension of the lips after orthodontic treatment by different appliances has received little attention. Aims: The purpose of this study was to compare the changes of vertical dimension of vermilions after standard and preadjusted orthodontic treatment. Setting and Design: Retrospective study. Materials and Methods: In this retrospective study, 60 patients (30 patients treated with standard edgewise appliances and 30 patients treated with preadjusted appliances) were randomly selected from the practice of two experienced orthodontist. Ratios between vermilion height and inter-commisural width were recorded on pre- and posttreatment photographs using Adobe Photoshop software. Data were analyzed with SPSS version 16 software and ANOVA analysis to compare vertical lip changes between two orthodontic systems. Results: The mean of vermilion height to inter-commisural width ratios after orthodontic treatment in preadjusted group ( P = 0.019) and standard group ( P ≤ 0.001) was significantly less than that before treatment. The reduction of this ratio after preadjusted orthodontic treatment was less than that in standard edgewise orthodontic treatment but this difference was not statistically significant ( P = 0.127). Conclusion: In this study, the vertical height of lips decreased significantly after orthodontic treatment in both groups and there was no significant difference in standard and preadjusted appliance. Therefore these changes must be discussed with patients before orthodontic treatments.