Selective application of cone -beam computed tomography in cephalometry

The objective of this chapter is to review the literature which describes the evolving roles of cone-beam computed tomography (CBCT) in cephalometric analysis for evaluation of dental and craniofacial structures and orthodontic treatment outcomes. Despite inherent limitations associated with conventional two-dimensional (2D) cephalograms, these continue as the mainstay for assessments of dental and craniofacial relationships and growth. The higher radiation doses plus lack of three-dimensional (3D) population norms and uncertainties about reference systems for comparisons are factors that have limited the use of CBCT for routine cephalometric analysis. While normative data for 3D CBCT volumes and new 3D paradigms are being established, the quantitative assessment of 3D dental and craniofacial form requires validation through comparison with traditional methods during this transitional period. This chapter has three specific aims regarding cephalograms generated from CBCT data: to enumerate various approaches, to quantify measurement accuracy, and to review the selection criteria and imaging parameters that should be considered in order to minimize radiation doses.