Abstract: Objective: To evaluate the changes of facial soft tissue before and after orthodontic treatment in adult women by using 3D scanning technology. Methods: A total of 80 adult women who received orthodontic treatment between June 2021 and December 2023 were divided into extraction group and non-extraction group (40 cases each). Before treatment (T0) and after treatment (T1), the two groups underwent facial 3D optical scanning to obtain 3D data of facial soft tissue. The indicators of line distance, angle, and volume of facial soft tissue between two groups before and after treatment were compared. Results: The changes of anterior and lower height, mandibular height, chin height, and lip width line distance in extractive group were smaller than those in non-extractive group (P<0.05). The changes of nasolabial angle in tooth extraction group were greater than those in non-tooth extraction group (P<0.05), and those in chin and lip angle were smaller than those in non-tooth extraction group (P<0.05). The changes of lip and chin volume in extraction group were smaller than those in non-extraction group (P<0.05). Conclusion: The facial soft tissue of adult women will change in different degrees before and after orthodontic treatment. Three-dimensional scanning technology has good application value in evaluating soft tissue changes before and after orthodontic treatment, and can accurately measure and compare the differences in line distance, angle, and volume of facial soft tissue before and after orthodontic treatment, which is conducive to the development of personalized orthodontic programs.

Key words: three-dimensional scanning technique, adult female, tooth extraction, orthodontics, soft tissue