Reproducibility of a New Method of Transfer of the National Head Position to the Cone Beam Tomography, Using Extracranial Marks

Objectives: The purpose of this research is to evaluate the reproducibility of a new method of transferring the natural head position to Cone Beam tomography using extracranial marks for orthodontic and surgical diagnosis.
Methods: 37 tomographs of the Maxillofacial surgery center (CIRMAX) were evaluated in the 2018 period, who had extraoral photographs in natural head position (NHP); and a tomographic volume. Tomographs of patients with dentofacial Deformity class I, II and III were included, both genders between 18 and 40 years. The tomographic recording was performed with resting lips, open eyes, no chin guard and maximum intercuspidation. Three dentist surgeons oriented the tomographic volume in NHP taking into account the extracranial marks obtained from the photographic records, as well as the evaluation of the linear and angular cephalometric measurements in the sagittal, coronal and axial plane. This procedure was performed twice by the same operator, in T0 and T1 (at 7 days).
Results: A concordance > 0.90 was observed; a statistically significant difference was found in two cephalometric measurements between the 2 times in the coronal and axial plane, but that does not represent clinical importance; there was a difference of greater reproducibility in the Sagittal plane, followed by the coronal plane, and finally the Axial plane.
Conclusions: Within the parameters of this study, the natural head position was reproducible in the three planes of space, the measurements in the Sagittal plane had less variation, followed by the coronal plane and finally the Axial plane.