Craniofacial imaging in orthodontics--past present and future.

Images of the craniofacial region are an important component of the orthodontic patient record. The gold standard that orthodontic records attempt to achieve is the accurate replication or portrayal of the "anatomic truth". The anatomic truth is the accurate three-dimensional anatomy, static and in function, as it exists in vivo. Despite the diverse image acquisition technologies currently available, the types and standards for imaging presently used in practice have been adopted in an effort to balance the anticipated benefits with associated costs and risks to the patient. Because of these considerations, orthodontists routinely use an array of two-dimensional static imaging techniques to record the three-dimensional anatomy of the craniofacial region. The development of an interactive 3D digital model of a patient's anatomy would greatly improve our ability to determine different treatment options, to monitor changes over time (the fourth dimension), to predict and display final treatment results, and to measure treatment outcomes more accurately. This review explores the different techniques of 3D imaging of the teeth, as well as the recent efforts to create the 'virtual orthodontic patient' by using 3D soft and hard tissue data. A brief overview of some of the commercially available 3D-based technologies, such as OrthoCAD and Invisalign is given at the end. The objective of this review is to provide the clinician with an overview of the currently used imaging methods along with those of the past and also a look at the innovations in craniofacial imaging that are likely to greatly enhance the depiction of craniofacial structures.