In vivo comparison of conventional and cone beam CT synthesized cephalograms.

OBJECTIVE To compare measurements from synthesized cone-beam computed tomography (CBCT) lateral cephalograms using orthogonal and perspective projections with those from conventional cephalometric radiographs. MATERIALS AND METHODS Thirty-one patients were imaged using CBCT and conventional cephalometry. CBCT volume data were imported in Dolphin 3D. Orthogonal and perspective lateral cephalometric radiographs were created from three-dimensional (3D) virtual models. Twelve linear and five angular measurements were made on synthesized and conventional cephalograms in a randomized fashion. Conventional image measurements were corrected for known magnification. Linear and angular measurements were compared between image modalities using repeated measures analysis of variance. Statistical significance was defined as an alpha level of .01. RESULTS With the exception of the Frankfort-mandibular plane angle (P < .0001), angular measurements were not statistically different for any modality (P > .01). Linear measurements, whether based on soft or hard tissue landmarks, were not statistically different (P > .01). CONCLUSIONS Measurements from in vivo CBCT synthesized cephalograms are similar to those based on conventional radiographic images. Thus, additional conventional imaging may generally be avoided when CBCT scans are acquired for orthodontic diagnosis.