Evaluation of the relationship between incisor torque and profile aesthetics in patients having orthodontic extractions compared to non-extractions

Objective: The aim of the present study was to evaluate the relationship between soft tissues aesthetics and incisor torque, as well as the effect of crowding, anchorage, and extraction pattern, in adult patients treated without extraction or with two or four extractions. Materials and methods: Seventy-seven subjects with permanent dentition were selected retrospectively. Among these, 24 patients were treated with four extractions, 24 with two extractions and 29 without extractions. Lateral cephalograms and photographies taken before (T0) and after (T1) treatment were retrieved. The amount of crowding and the type of anchorage were recorded, and a cephalometric analysis was performed. A one-way ANOVA was used to compare the variables within and between groups. Linear regressions were performed to evaluate the effect of different predictors on soft tissues variables at T1. Results: The statistical analysis showed no differences within and between groups for soft tissue aesthetics. A significant reduction of the angle obtained from the intersection of Frankfurt plane and mandibular plane was observed in the four-extractions group, and a significant proclination of the lower incisors was observed in the two-extraction group. Linear regressions revealed that the change in soft tissue profile aesthetics was affected by the type of anchorage and the two-extractions pattern. Conclusions: Similar soft tissue aesthetics were observed after treatment in the three groups, despite the presence of some skeletal and dental differences. Clinical relevance: A well-controlled incisor torque helps to preserve soft tissues aesthetics. The type of anchorage could influence soft tissues.