[Studies on the strength and the cutting performance of dental canal reamer. (I) Strength properties of raw materials of dental canal reamer and these standard (author's transl)].

Pulp canal reamers have been widely used for dental treatments of the root of teeth. The work's accuracy and cutting capability of these instruments are treated by the standarization of JIS and ADA etc. Especially Japanese industrial standarization (JIS) treated the dimensions of the configurations, materials and ability of dental canal reamers. But there is no report of the studies on the work and fracture strength of these dental instruments. So, this paper makes a report on these problems, which are the measurements of the diameter of the bite tips, are concerned the strength of the raw materials of dental canal reamers and are compared with the standarization (JIS) of these instruments. Test of the raw materials of reamers are tensile properties and are measured the strength and elasticity of these materials. And phase of fracture of these materials are investigated with the scanning electric microscope and the fracture modes are compared with the tensile strength properties.