Abstract: Objective: To evaluate the three-dimensional (3D) perioral soft tissue changes after orthodontic treatment in patients with bi-maxillary protrusion using light-based scanners. Methods: Twenty-four adults with bi-maxillary protrusion were treated by extraction of four first premolars. Lateral cephalograms and 3D facial scans were obtained before treatment (T1) and immediately after debonding (T2). Superimposition was performed, and 27 perioral landmarks were identified. Paired student t-test and one-way analysis of variance were performed. Results: The mean retraction distances of the upper and lower incisors were 6.12 mm and 4.58 mm, respectively. The upper lip moved inferoposteriorly, and the lower lip moved superoposteriorly. The relative ratios were 42%-53% in the upper and 22%-82% in the lower. The lip corners moved superoposteriorly. Conclusion: Facial scanning by white structured light scanners can efficiently evaluate 3D perioral soft tissue changes in bi-maxillary protrusion patients. Obvious backward movement of the upper and lower lips was observed.

Key words: Light-based scanners, Bi-maxillary protrusion, Three-dimensional