Fig. 1

The construction of the landmark for the determination of asymmetry. (A) ML, left molar; MR, right molar; PI, the mesial tip of the papilla; CP, the center of the palate in the horizontal plane. The PI, MR, and ML created the horizontal plane (red). A line (green) perpendicular to the MR-ML line was projected to the PI. The intersection point of this mid-palatal line and the MR-ML line determined the CP. (B) The angle on the right side was defined between PI-CP and PI-MR line (aMRCP, green). The angle on the left side was defined between PI-CP and PI-ML line (aMLCP, yellow)