Changes in the Soft Tissue Chin Area by Retraction of Mandibular Orthodontic Incisors - A Retrospective Study

Abstract

Introduction: In the face the lip and the chin area are more noticed. The soft tissue changes following incisor retraction by the cephalograms has been viewed as clinically advantageous and important for orthodontic treatment planning and doctor patient correspondence.To evaluate area and morphology changes of soft tissue chin after orthodontic incisors retraction.
Materials and Methods: One hundred male subjects with bimaxillary protrusion requiring extraction of four premolars were included in the study. Cephalograms before (T0) and after (T1) orthodontic treatment were taken. The soft tissue changes, including the area, thickness and morphology were evaluated. Paired-t tests was done. Pearson correlation analyses and backward multivariate regression analyses are done to recognize the relationship amongst the incisor retraction and soft tissue changes.
Results: A significant increase in the soft tissue thickness, and a significant decrease in the soft tissue thickness of B-B′ were seen. No statistically significant changes in the area of soft tissue chin and lower lip were noted. Pearson coefficient among the thickness changes of B-B′ and the retraction of lower incisors was − 0.376. The multiple correlations between the soft tissue thickness changes and incisor retractions were Y = 1.02–0.42a + 0.42b for L1c-LL, and Y = 0.17–0.31b for B-B′.
Conclusion: The orthodontic incisor retraction could cause soft tissue thickness changes (i.e. an increase in L1c-LL and Pog-Pog’ and a decrease in B-B′) without area alterations.