Immediate effect of clear aligners and fixed appliances on perioral soft tissues and speech

Abstract

Objectives: To compare the immediate three-dimensional (3D) perioral soft-tissue changes and impact on speech induced by clear aligners and fixed appliances. Materials and Methods: In this repeated-measure experimental study, stereophotogrammetric 3D photographs of 40 participants were recorded before and immediately after the introduction of clear aligners and fixed appliances. The 3D surface meshes were registered to quantify changes in the direction and magnitude of nine soft tissue landmarks located on the upper and lower lips. Self-reported speech disturbance was evaluated using a questionnaire. Data were analysed using repeated-measures analysis of variance. Results: In the vertical plane, the clear aligners induced inferior displacement (range 0.4-1.5 mm) for all nine landmarks (P