Condylar positioning in orthognathic surgery: a cone beam computed tomography-based in vitro analysis of a positioning method

ABSTRACT

Aim: Orthognathic surgery aims to correct facial skeletal deformities and the correct condylar positioning is very important for stable results. The aim of the present study was to verify the occurrence of changes in the postoperative condylar positioning in artificial skulls with a skeletal Class II maxillomandibular relationship submitted to bilateral sagittal split osteotomy when the method of cephalometric data transfer was used. Methods: Ten skeletal Angle class II polyurethane skulls were used with metallic markers in the articular surfaces of the temporomandibular joint and mandibular condyles. The skulls were submitted to preoperative and postoperative cone beam computed tomography before and after the bilateral sagittal split osteotomy. To verify the condylar positioning, measurements between the distances of the markers at the temporal bones and mandibular condyles were taken in the coronal and sagittal views by the DISTANCE tool of the iCat Vision software. All measurements were obtained by one examiner in the preoperative and postoperative CBCTs, tabulated and submitted to statistical analysis by the Wilcoxon test with a level of significance of 5% (p<0,05). After 15 days of the completion of the first data collection, all measurements were redone to determine the random and systematic error by the Intraclass Correlation Coefficient. Results: With the exception of the average of the lateral-medial distance (from the measurements between the medium left markers only), the averages of the anterior-posterior distances (only in the left posterior and lateral right markers) and the vertical average (only in the central markers) showed no statistically significant differences between the preoperative and postoperative distances of the metallic markers. Conclusion: Even when using the method of cephalometric data transfer, variation of the condylar positioning occurred between the preoperative and postoperative periods. This variation occurred only in a few points of the mandibular condyles