Three-dimensional soft tissue changes in orthodontic extraction and non-extraction patients: A prospective study.

Abstract

To assess the soft tissue changes in orthodontic extraction and non-extraction patients on 3D stereophotogrammetric images. 23 extraction (22.2±9.2years) and 23 non-extraction (20.3±11.1years) consecutive patients were enrolled at the Sections of Orthodontics at Aarhus University and at University of Naples Federico II. All patients had a first 3D image taken after bonding of brackets on the upper incisors (T0), and a second 3D image (T1) after space closure in the extraction group or at insertion of the first SS or TMA rectangular wire in the non-extraction group. The 3D images were captured with 3dMDFace System and analysed with 3dMDVultus Software. After placing 19 landmarks, 15 measurements were obtained. Intragroup changes were analysed with paired t-test and intergroup changes with unpaired t-test (P<.05). Superimpositions of the 3D images at T0 and T1 visualized with colour-coded maps showed that soft tissue changes primarily happened in the perioral area in both groups. The Nasolabial angle increased significantly in the extraction group (3°±4.1, P=.002), while it decreased in the non-extraction group (-1.5°±5.5°, P=.002). There was a significant difference between the two groups (4.4°, P=.004). 3D comparison of the soft tissues in the extraction and non-extraction groups showed statistically significant, but clinically limited differences in the perioral area. The Nasolabial angle was significantly larger at T1 in the extraction group compared with the non-extraction group.