Abstract: Objective: To evaluate the three-dimensional changes of soft and hard tissues in adult females after extraction orthodontic treatment. Methods: A total of 40 female cases were included, and the CBCT data before and after orthodontic treatment were quantitatively analyzed using Dolphin software. Results: There is statistically significant difference in the displacement of upper and lower lips, as well as the soft tissue around nasolabial folds along the sagittal direction. The changes of soft tissue around nasolabial folds showed a gradual increase (NFL3＞NLF2＞NFL1) and a gradual decrease from the inside to the outside (L2＞NLF2＞L1). There was a moderate positive correlation between incisor retraction and changes in lip tissue (r=0.52), as well as a moderate positive correlation between upper canine retraction and changes in soft tissue around nasolabial folds(r=0.63). Conclusion: The convex facial profile and lip morphology can be effectively improved after extraction orthodontic treatment in adult females. The retraction of incisors and canines can be used to predict changes of lips and soft tissue around nasolabial sulcus in the sagittal direction. Although the soft tissue around nasolabial folds showed negative changes, further research is needed to determine whether the folds in the nasolabial folds will deepen.

Key words: tooth extraction, CBCT, nasolabial sulcus, soft tissue, orthodontic