Estimation of anterior tooth axis and alignment using cone-beam computed tomography

The three-dimensional tooth axis or longitudinal axis of tooth is an important as a morphological reference axis; however general definition of the tooth axis has not been established. In general, previous methods of calculating tooth alignment have relied on models cast from molds of patients' mouths, which have then been measured by methods such as touching the stylus of a 3D measurement device to feature points on teeth and using a 3D laser measuring device. In this study, we developed a global coordinate system based on maxillary and mandibular feature points from 3D reconstructions using in vivo cone-beam computed tomographic image data, devised a procedure for automatically calculating the tooth axis of the maxillary and mandibular front teeth and the absolute 3D position of the tooth alignment.