[Measurement errors in 3D cephalometrics: about the buccal cranio-facial analysis].

The development of three-dimensional radiological techniques generating low levels of radiation, like computed tomography and positron emission tomography with cone beam, has made it possible for orthodontists to utilize three dimensional cephalometry for certain complex clinical cases instead of conventional two dimensional imagery. Nevertheless, these new techniques rely on the identification of the most dependable anatomic landmarks. Fifteen randomly selected orthodontists were asked to identify on a computed tomography film 33 points that were chosen for a buccal cranio-facial analysis because they have been traditionally recognized for their reproducibility. The results confirmed the high reliability level of the reference point vestibion that is related to the semi-circular canals. They showed, in the same way that conventional 2D cephalometry does, that each landmark presents a cloud and dispersion characteristic and that the most reliable landmarks are based on easily identifiable anatomic structures like foramens and osseous points.