It is not difficult to express a 3D object in 2D, but on the contrary, 3D object cannot be represented accurately using 2D data due to lack of data between reference planes. The same thing has happened so far in the diagnosis process for orthodontic treatment. There are limits to accurately depicting a three-dimensional human body through two-dimensional photographs and cephalograms, and orthodontists need a lot of effort and experience to develop their visualization skills. Considering this, it is not surprising that attempts to use 3D data in orthodontics have been made since the early 1900s. Later, when the cephalogram was developed by Broadbent, it was ultimately attempted to determine the patient's three-dimensional positional relationship by taking images simultaneously from the lateral and frontal sides.

The full-fledged use of 3D data in dentistry began with the development of CBCT in 1996. Afterwards, intra-oral (model) scanners that clearly indicate the condition of the dentition became popular, and recently face scanners have been used clinically to analyze facial soft tissues. Unfortunately, there is no 3D data that well represents all of the skeleton, dentition, and facial soft tissues required for orthodontic diagnosis, so it is inevitable that CBCT, intra-oral scanner, and face scanner must be integrated and used according to the purpose of use. Therefore, in order to utilize 3D images well, it is necessary to understand the characteristics and limitations of each 3D data and the principles of integration of various 3D data.

Through this presentation, I would like to learn about 3D images that can be used in the field of orthodontics and present their effective use in orthodontics.