抄録
Since ultra-high speed cutting device had been introduced into dental practice, the demand for friction-grip type of burs and stones for the device has increased. The diameter of the shank of the instruments (burs and stones) has, however, not been standardized international-wise as yet despite a standard-to-be one in 1/16 inch or 1.5875 millimeters.
The council on Dental Research of American Dental Association adopted the specifications for excavation burs and diamond rotary instrument [1] formulated by the Dental Materials Group of International Association of Dental Research in December 1963.
In the Specifications, the shank dimensions of Table 2-4a and 4b specify the shank diameters of instruments for friction grip type in inches.
We have found the difference of shank-diameter of the instruments between products and the standard-to-be and its variations among the products of various manufacturers. These variations among the products are evidently inconvenient for practicing dentists employing these instruments which are made by various manufacturers and, at the same time, it is true of the manufacturers who make the devices.
The authors in this study attempted to determine the variations in the diameter of the friction-grip type of cutting instruments for ultra-high speed cutting device.
