It is clearly inevitable to make precise holes in the proximal surfaces of the abutment teeth to get a highly stable clinical outcome with the recently described exciting dental rehabilitation method, e.g., Pin Bridge System (Yamashita et al., 1996). However, using a conventional preparation pin instrument, sometimes chipping of the enamel and/or the instrument bar breakage has been experienced. This article describes a newly-developed pin-hole drilling instrument using ultrasonic vibration.

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... ce the tip of this preparation pin instrument does not rotate and the required pressure during preparation pin holes is extremely less than that for the conventional instrument, it is easy to hold the instrument precisely in the same position without any adversed effect such as enamel chipping or drill breakage. Finally, the described precision of the preparation hole diameter was clinically acceptable. It was concluded that the new device for making a hole in the proximal surface of the abutment teeth is very useful with the special features.