Fig. 3

Detailed procedure of locating the measurement plane of the selected tooth. The correlated planes were determined by 3 intersected guide lines with different colors representing the correlated planes, which are yellow for axial plane, green for sagittal plane, and purple for coronal plane. a Adjust the location of the axial plane by passing the yellow guideline through the CEJ of the selected tooth in both the coronal and sagittal views, then rotate the purple guideline until the intersecting line is the shortest. b Rotate the green guideline until it passes through the root apex and the midpoint of the incisal margin. c Rotate the purple guideline until it passes through the root apex and the cusp. d To ensure precise and accurate identification of anatomic structures, the largest labiolingual section displayed in the sagittal view was chosen as the measurement plane. A 10.8-mm dehiscence (left) and a 3.9-mm fenestration (right) are shown in the measurement plane