[Some technical problems in three-dimensional cephalometrics].

Two-dimensional(2D)cephalometrics is an important diagnostic technique in dentistry. Three-dimensional(3D)cephalometrics is becoming a hot point along with the popularity of cone-beam CT(CBCT). However, the 3D cephalometric technique, like 2D cephalometric technique, there are many technical problems needed to be solved. In this article, several topics, including multi-source of 3D cephalometrics, the head position in 3D cephalometrics, the difficulty of landmark indication, norms for 3D cephalometrics and superimposition in 3D imaging, are discussed.