Extraction of Midsagittal Planes for Craniofacial Hard and Soft Tissue by using a Surface-based Method and Their Degree of Coincidence

Abstract

The purposes of this study were to present a procedure for extracting midsagittal planes of the cranio-maxillofacial skeleton (hard tissue) and the facial soft tissue of patients with jaw deformities by using a surface-based method, and to assess whether there were differences between those two plans. Ten patients with jaw deformities who had undergone CT scanning for diagnostic purposes at pretreatment were included in this study. Three-dimensional virtualized patient models of hard and soft tissue were generated from CT scan data of the patients. The midsagittal plane for hard tissue (MSP_h) and for soft tissue (MSP_s) were extracted by using the surface-based method. The angular and distance errors between determined MSP_h and MSP_s were calculated. The average angular and distance deviation were 0.532±0.226° and 0.169±0.139 mm, respectively. From these results, the difference between MSP_h and MSP_s was considered to be minimal clinically. This study suggested that surface data of soft tissue may be useful to predict the symmetry properties of hard tissue in the diagnosis of jaw deformities.