The Influence of Bilateral Sagittal Split Ramus Osteotomy on Submental-Cervical Aesthetics

Abstract

The effect of orthodontic-surgical treatment on submental-cervical region was evaluated in a very limited number of studies. The aim of this study was to evaluate submental-cervical soft tissue contour changes following mandibular advancement and set-back procedures via bilateral sagittal split ramus osteotomy. Sixty-seven patients were included in this study. Group 1 consisted of 27 skeletal Class II patients who underwent mandibular advancement surgery, whereas Group 2 consisted of 40 skeletal Class III patients who underwent mandibular set-back surgery. Various linear and angular measurements were performed on pre-operative and sixth month post-operative cephalometric radiographs. A new method was used to evaluate the amount of sagging at submental region. The submental length did not change in Group 1; however, it decreased significantly in Group 2 (P<005). The angle between submental plane and facial plane decreased to 959 degrees from 988 degrees in Group 1(P<005), whereas it increased to 931 degrees from 882 degrees in Group2 (P<005). The change of submental soft tissue sag was almost stable in Group 1, while 034mm increase of sag was observed in Group 2. This increase was not statistically significant (P>005). Mandibular set-back and advancement procedures do not remarkably change the submental sag following approximately 6mm jaw movement. Although mandibular advancement did not significantly effect submental length, soft tissue followed mandibular set-back with a ratio of 1:1 at C-point to projection of soft tissue pogonion and 1:07 at C-point to soft tissue menton distances.