[Studies on the performance of the dental air turbine handpieces. (Part 2) Classification and rotational performance of the dental air turbine handpieces (author's transl)].

For the purpose of the clinical and technical uses, air turbine handpieces are widely used for the high speed cutting instruments. And then, there are the many kinds of air turbine handpieces which are classified with the standard, minutia and torque types etc. So, in this paper, we examined the rotational properties of air turbine handpieces in the consideration of these classifications. And the relations between the reduction of the rotational speed and the rotational loads on the handpieces are fundamentally investigated. As the results of these investigations, it was revealed that rotational forces of the toque type air turbine are very excellent and the rotational speed of the air bearing type air turbine is higher than that of other type handpieces. And we obtained the practical properties of the rotational ability of air hand pieces.