Speed variability of air-driven motors in the self-threading pin technique.

Abstract

Effective pin placement is dependent upon correct preparation of the dentine channel. Various factors contribute to the success or otherwise of this channel preparation. One such factor is the rotational speed of the twist drill. It is widely recommended that the twist drill be operated within the 500-800 rpm speed range, in order to prevent a temperature rise in the pulp during the cutting process. This paper examines the ability of air-driven dental motors, when coupled to two speed-reduction handpieces with differing reducing ratios, to operate within this range. The results reveal a wide variation in the speed ranges of the motors tested. Of the two types of handpiece examined, it appears that a 10:1 speed reduction is appropriate for the majority of motors.