Three dimensional quantitative study of soft tissue changes in nasolabial folds after orthodontic treatment in female adults

BACKGROUND: With the popularity of medical aesthetic programs, some female adults who will or are undergoing orthodontic treatment often wonder whether orthodontic treatment has adverse effects on the nasolabial folds (NLFs). The aims of the study were to investigate any potential changes in the NLFs and associated peripheral soft tissues after orthodontic treatment of female adults. METHODS: This study compared changes in the NLFs and peripheral soft tissues in female adults undergoing orthodontic treatment using the 3dMD Face system (3dMD, Atlanta, Ga). A total of 52 adult female patient cases (24 teeth extraction, 28 non-teeth extraction) were included to evaluate the effects of different orthodontic treatment regimens on the NLFs and peripheral soft tissues. RESULTS: In the NLFs area, the landmarks of the extraction group were all significantly negatively changed (P < 0.001; the NLF2s average value was − 0.72 mm), and the upper and middle parts of the landmarks were negatively changed in the non-extraction group (P < 0.05; the NLF2s average value was − 0.22 mm). Compared to the non-extraction group, the negative changes in the extraction group were more pronounced (P < 0.005). In the lip region, all landmarks in the extraction group were negative changes (P < 0.05; upper lip (ULP) = − 0.93 mm, lower lip (LLP) = − 1.46 mm), and most landmarks in the non-extraction group were positive changes (P < 0.01; ULP = 0.55 mm). In the cheek area, the left and right buccal of the extraction and non-extraction groups were all negatively changed (P < 0.05), and there was no significant difference between the two groups. CONCLUSION: After orthodontic treatment, the NLFs showed negative changes, which were more obvious in the extraction group. The lip soft tissue had a negative change in the extraction group and a positive change in the non-extraction group, indicating that orthodontic treatment affected the soft tissue around the nasolabial sulcus, and that tooth extraction would lead to more negative changes.