Superimposed CBCT measurements. Blue is initial and red is final. ΔU1(x) refers to the distance between lines drawn through the midpoint of the incisal edges of the superimposed target tooth perpendicular to the A-P axis (the plane of prescribed tooth movement). ΔU1(s) is the length of the line connecting the midpoint of the incisal edges of the superimposed target tooth. ΔApex refers to the length of a line connecting the change in apex of the superimposed target tooth. Rotation angle is the angle created by the intersection of lines drawn from the midpoint of the incisal edge to the apex of the target tooth. The apex of this angle is considered the center of rotation. Tooth length refers to the distance from the midpoint of the incisal edge to the apex of the target tooth from the initial X-ray. Crown length is the portion of the tooth length that is coronal to the bone. Bone to C-rot. is the section of tooth length between the center of rotation and a line connecting the most coronal aspect of the faciolingual crestal bone. ΔU1(o) refers to the A-P change in the midpoint of the superimposed incisal edge of the opposite central incisor, the one that was not the target tooth. ΔU1(t) refers to the distance between midpoint of the superimposed incisal edge of the contralateral central incisor, to the midpoint of the incisal edge of the target tooth.
