Three-dimensional analysis of lip and perioral soft tissue changes after debonding of labial brackets

Abstract

Objectives – To evaluate the possible soft tissue changes after debonding of labial brackets using three-dimensional (3D) images acquired by a laser scanner. Methods – On the same day, 3D facial scans were taken immediately before debonding (T1) and immediately after debonding (T2) from 53 patients, and follow-up scans were taken 3 months after debonding (T3) from 31 patients. To compare the scans, superimpositions were performed and shell-to-shell deviations were used for quantitative analysis. Results – Shell-to-shell deviation map showing warm colors in lip and perioral tissue represented the retrusion of soft tissue after bracket removal. Soft tissue retrusion was significant for all landmarks immediately after debonding (T1–T2) and 3 months after debonding (T1–T3). Gender, bracket type, and the lip thickness variables did not show a clinically significant influence on the amount of soft tissue retrusion at the T1–T3 period. Lip corners and vermilion borders were significantly retruded at the T1–T3 period more than other perioral areas. A negative linear relationship was found in the amount of soft tissue retrusion immediately after debonding (T1–T2) and from debonding to 3 months after debonding (T2–T3). Conclusion – Three-dimensional imaging showed significant changes in lip and perioral soft tissue after debonding of labial brackets. Clinically significant changes, approximately 2 mm of retrusion, occurred in the mouth corners bilaterally. Vermilion border landmarks also demonstrated significant changes in more than 1 mm. However, it was not possible to predict the soft tissue changes. A wide range of individual variability in the response to treatment and soft tissue adaptation was noted.