Assessment of lower lip changes following incisor displacement in 92 orthodontically-treated adults.

Aim: A retrospective assessment of the lower lip changes conse- quent to incisor displacement in correction of malocclusion in a sample of 92 post-adolescent subjects. Methods: The study sample comprised two groups, subdivided according to the direction of incisor movement achieved during orthodontic treatment: the retraction group (Group 1), made up of 41 patients in which the maxillary incisor had been moved in a palatal direction (palatal tipping); and the protraction group (Group 2), composed of 51 patients who had undergone labial movement of the upper incisors (labial tipping). In order to evaluate the mean changes in lower lip position, and consequent alterations in the quality of the patients’ profiles, between T1 (prior to orthodontic displacement of the incisors) and T2 (fol- lowing treatment), the following parameters were measured on lateral head film X rays: variation in lower lip vermilion thick- ness (dLVT); variation in lower lip sulcus depth (dLLSD); variation in lower vermilion height (dLVH); variation in expo- sure of the upper and lower incisors in relation to the lower stomion (dIs-STOi and dIi-STOi, respectively); variation in upper and lower incisor tipping with respect to the palatal plane (d1/PP and dinf1/PP); and variation in lower facial height (dLFH).