Upper lip changes correlated with maxillary incisor movement in 65 orthodontically treated adult patients.

Aim: To describe the behavior of the upper lip components following orthodontically induced movement of the maxillary incisor in a sample of 65 adults.

Methods: The study sample was divided into 2 groups: the retraction group, made up of 35 patients in whom the incisor had been moved in a palatal direction (tipping), and the protraction group, consisting of 30 patients who had undergone labial movement of the incisor (tipping). To evaluate the mean changes in lip position and quality of the patients' profiles between T1 (before movement of the incisor) and T2 (after movement of the incisor), we measured the following parameters: variation in upper lip thickness (DUVT), variation in the depth of the labial sulcus (DULSD), variation in vermillion height (DUVH), variation in upper lip length (DULL), variation in maxillary incisor exposure (DIs-STOs), and DSTOs and STOi, which indicate a variation in the gap between the lips.

Results: In the retraction group, all soft tissue parameters showed significant changes at T2, except for DUVT and DULL, while in the protraction group, the significance of the mean changes was decidedly lower and resulted higher for only DULSD and DUVT. Nevertheless, multiple linear regression analysis highlighted the unfeasibility of predicting the behavior of the dependent (cutaneous) variables except for DUVH and DULSD in the protraction group.

Conclusion: The results obtained highlight a pronounced variability among the patients studied and the impossibility of accurately predicting the behavior of the soft tissues following movement of maxillary incisors.