Retraction of the maxillary incisors and change in the infranasal soft tissue part of the face

Introduction: The potential effect of maxillary incisor retraction on infranasal soft tissue part is debatable . Aim: This study aims to evaluate the soft tissue changes of the infranasal part of the face after retraction of the maxillary incisors following Begg mechanotherapy. Materials and Methods: The parent sample consisted of one hundred patients. Of them, 40 female and 20 male patients had class II division 1 malocclusion whereas 24 male and 16 female patients had class I malocclusion with anterior protrusion. All the patients were treated with fixed appliances (Begg’s technique following extraction of either all first premolars or only upper first premolars) for an average period of one year and six months .Each patient had lateral skull radiographs taken before commencement of treatment, at the end of the first stage of treatment; that is as soon as the incisors reached an edge -to- edge relationship; and at the end of treatment 2 months after appliances were removed. Chi-square test was applied as the measures of associations, T-test was used to compare the means. The soft tissue parameters compared between pre-treatment and post-treatment were as follows: Labrale superior(Ls) to E line, Labrale inferior(Li) to E line, Sulcus superior(Ss) to E line , Sulcus inferior(Si) to E line, lower lip to H line, upper lip to profile line, lower lip to profile line, Z angle, Nasolabial angle, Labiomental angle and H angle. Results: Soft tissue analysis revealed that significant changes were noted in case of labrale superior to E line, labrale inferior to E line, Z angle, H angle, nasolabial angle and labiomental angle whereas non-significant changes were noted in case of sulcus superior to E line, sulcus inferior to E line , H line and profile line relative to both upper and lower lips. Conclusions: The findings of the present study indicates that retraction of maxillary incisors is a viable option for a desirable decrease of lip procumbency although the amount of this reduction varies from person to person.