Kephalometrische und photogrammetrische Analysen von Weichteilveränderungen des Gesichtsprofils nach orthognathen chirurgischen Eingriffen

Abstract

For dysgnathia of Angle Class II and III, the goal of therapy is not only the correction of dental and basal deformities itself, but also to achieve attractive aesthetics with improvement of the facial profile. For this aspect, it is of great importance to predict the changes in soft tissue that result from movement of hard tissue precisely. The aim of this study was based on cephalometric and two-dimensional photogrammetric profile analysis to determine the correlations between soft and hard tissue movement and to compare both methods. Four groups of patients were examined cephalometrically (hard and soft tissue movement) and two-dimensional photogrammetrically (soft tissue movement) pre- and postoperatively: Patients with bimaxillary osteotomy (BIMAX) with Angle Class II (n = 15), BIMAX with Angle Class III (n = 23), patients with bilateral sagittal split ramus osteotomy (BSSRO) with Angle Class II (n = 16) and patients with BSSRO with Angle Class III (n = 13). In the BIMAX patient group both methods, two-dimensional photogrammetry and cephalometry, showed pre- and postoperatively significant differences (p <0.05) for facial convexity angle, labiomental angle and lower lip length. Further, significant correlations between changes of soft and hard tissue angles occurred cephalometrically and two-dimensional photogrammetrically for BIMAX Angle Class III patients. However, significant correlations for BIMAX Angle Class II patients could only be determined by two-dimensional photogrammetry. In analyzing horizontal movement of soft and hard tissue landmarks significant correlations with both measurement methods were found for corresponding landmarks A and Sn, Si and B and Pg 'and Pg. For vertical movement significant correlations were found cephalometrically between Sn and A and 2 -D photogrammetrically for Pg 'and Pg. In BSSRO patient group cephalometry and two-dimensional photogrammetry revealed highly significant differences between pre- and postoperative facial convexity angle (p <0.001, p = 0.003). Significant differences between pre- and postoperative labiomental angle were, however, only revealed for BSSRO Angle Class II patients (p <0.001, p = 0.044). Only for two-dimensional photogrammetry were found significant correlations between soft tissue distance, lower lip length and hard tissue angles and distances for both Angle classes. Two-dimensional photogrammetry and cephalometry showed for both BSSRO Angle classes horizontally and vertically significant correlations between pre- and postoperative movements of the corresponding soft and hard tissue landmarks Pg ' and Pg as well as Si and B. Both methods, cephalometry and two-dimensional photogrammetry, remain reliable methods. They also have the potential to complement each other. Valid data for the creation of a prediction can be supplied for planning an osteotomy.