Cephalometric Angular Measurements of the Mandible Using Three-Dimensional Computed Tomography Scans in Koreans

Abstract

Background: We conducted this study to analyze the values of the key cephalometric angular measurements of the mandible using 3-dimensional (3D) computed tomography scans.

Methods: In the 106 enrolled patients, a 3D cephalometric analysis was performed to measure the angular variables of the mandible. These values were compared between the two sides and between the two sexes.

Results: The frontal measurements revealed that the mandibular body curve angle was larger on the left (Lt) side (right [Rt], 141.24±7.54; Lt, 142.68±6.94; P=0.002) and the gonial angle was larger on the right side (Rt, 134.37±8.44; Lt, 131.54±7.14; P<0.001). The sagittal measurements showed that the gonial angle was larger on the right side (Rt, 134.37±8.44; Lt, 131.54±7.14; P>0.05). Further, the transverse measurements revealed that the mandibular body curve angle was larger on the right side (Rt, 140.28±7.05; Lt, 137.56±6.23; P<0.001).

Conclusions: These results provide an average of the mandibular angular measurements for the Korean population, establishing a standard for determining surgical patient groups and outcome evaluations in the field of mandible contour surgery.

Keywords: Angular; Cephalometry; Mandible; Three-dimensional.

Fig. 1. Schematic representation of frontal landmarks and measurements

FH, Frankfort horizontal plane; Co, condylion; Med Co, medial condyle; Lat Co, lateral condyle; Go, gonion; 1, ramal mediolateral inclination; 2, condylar width; 3, condyle to midsagittal plane; 4, gonion to midsagittal plane; 5, gonial angle; 6, mandibular body angle.

Fig. 2. Schematic representation of sagittal landmarks and measurements

FH, Frankfort horizontal plane; Co, condylion; Go, gonion; Me, menton; 1, condylar height; 2, condylar anteroposterior inclination; 3, ramal anteroposterior inclination; 4, ramal length; 5, gonial angle; 6, mandibular body length.

Fig. 3. Schematic representation of transverse landmarks and measurements

Me, menton; MBC, mandibular body curve; Go, gonion; 1, menton angle; 2, mandibular body length; 3, anterior mandibular body length; 4, posterior mandibular body length; 5, MBC angle.

Fig. 1. Digital Imaging and Communications in Medicine (DICOM) Tag Information. The red box indicates a DICOM Tag (0028, 0030 Pixel Spacing), and other information stored with this DICOM Tag.

Fig. 2. Three-dimensional-computed tomography (3D CT) reconstructed model. It is difficult to use one 3D CT reconstructed image as a reference for another due to the different absolute values generated by differing conditions such as display field of view, tilt, and window, as in the two images shown here.