Figure 1 Cone-beam computed tomography images identifying the baseline plane of a right maxillary first molar for subsequent measurements of anatomical landmarks. (A) The axial plane view shows that the blue line has been adjusted to be parallel to the mesial and distal crown margin tangential line and bisects the baseline plane. Similarly, the green line has been adjusted to be parallel to the buccal and lingual crown margin tangential line and bisects the baseline plane. (B) The sagittal plane view shows that the tooth has no mesial-distal tilt. This was achieved by adjusting the longitudinal axis of the target tooth parallel to the blue line. (C) The coronal plane view shows that the tooth has no buccal-lingual tilt. This was also achieved by adjusting the longitudinal axis of the target tooth parallel to the green line.