Recent advances of the dentistry have produced remarkable increasements and variations of both the quality and quantity of informations in which those who concern themselves with dental clinics are interested. The introduction of the computer system is concidered to be indispensable in order to store and manage those great amounts of informations effectively.

Actually many works have been done with the help by means of the computer system. But as far as we know, in many cases, they can be collected only by the processing of data for convenience rather than by analizing of true value of individual work.

We now insist on the necessity of the computer system which can be able to store and manage to supply many valuable informations for orthodontics, and obtaining other additional informations.

In addition, it is very important and useful that those systems perform the conversational processing, and various statistical analysis (involving multi-variate statistical analysis) can be easily and simply applied.

For those reasons, we have been developing the clinical data processing system for orthodontics (named "ORDAS"), and obtained some interism findings.

A theoretic concept of the system and clinical approches of the methods of the computer has been presented in relation to use of retrieving and analysed stored clinical datas in orthodontics.