Dynamic changes in morphometric analysis in patients following Class III bimaxillary surgery.

BACKGROUND

Prognathism of the mandible is a skeletal Class III abnormality, caused either by excessive forward growth of the mandible or maxillary underdevelopment.

OBJECTIVES

The aim of the study was to assess dynamic changes in morphometric analysis on subjects presenting with Class III malocclusions before orthodontic treatment, before bimaxillary surgery and after surgery.

MATERIAL AND

METHODS

The sample consisted of 30 non-growing patients, at the age of 18 to 30, treated with mandibular set-back sagittal split osteotomy and maxillary Le Fort I advancement. Cephalometric analysis by Segner and Hasund was performed. Lateral cephalograms were taken at the beginning of orthodontic treatment (T0), immediately before surgery (T1) and at least 3-6 months after surgery (T2).

RESULTS

The results showed that there was normalization of the cephalometric variables after surgery. In the sagittal plane the following skeletal changes were observed: preoperative anterior mandibular growth confirmed by SNB increased angle was significantly reduced after surgery; preoperative decreased SNA angle largely increased after surgery. Statistically significant GntgoAr mandible angle decreased after surgery in relation to the beginning state. Also, the H angle was increased as a result of orthodontic-surgical treatment which influenced positively on face esthetics.

CONCLUSIONS

The results of our study indicate that there was a significant improvement in the correlation between soft and hard tissue change in the facial profiles of the Class III bimaxillary surgery patients, which was improved by the H angle. The face's photographs and cephalometric analysis indicate, after the operation there is a decrease of total face length, but the lower part still remains longer than a middle part of the face.