SOFT TISSUE SIMULATIONS IN ORTHOGNATHIC SURGERY: COMPARISON BETWEEN DATA ACQUIRED BY MULTISLICE AND CONEBEAM CT

After many years of orthognathic surgery there are still many difficulties in predict the extent of the skeletal movements, the response of soft tissues and the clinical final aspect. The objective of this work is to compare the data acquired by the Multislice CT and Conebeam CT redesigned with a new software (SurgiCase CMF®) that makes possible for the surgeon to foresee the final result. Materials and Methods: 20 patients with cranio-maxillo-facial deformations have been submitted before the surgery to TC study; a group of 10 patients were studied with Multislice CT and a group of 10 patients with Conebeam CT. The data have been 3D reconstructed. Using the program SurgiCase CMF® were simulated various osteotomies in a three-dimensional virtual environment by applying different surgical procedures. At the end of the simulation of the hard tissues the simulation of the soft tissues was possible. Results: results obtained with 10 cases simulated from a CBCT data had been compared with 10 cases simulated from a MSCT. MSCT simulations defined an average absolute error of 0,75 mm, with a standard deviation of 0,78 mm, pointing out a percentage of error below 2 mm of 90,6%. CBCT simulations defined an average absolute error of 0,94 mm, with a standard deviation of 0,90 mm, pointing out a percentage of error below 2 mm of 86,80%. Discussion: The preliminary results allow to conclude that programming orthognathic surgery in skull-maxillofacial deformity using CBCT acquisition is reliable and can become the method of choice for the less radiation exposure than the MSCT