PURPOSE: To properly polish a curved cutting edge surface of a curette used for elaborately planing the root of a tooth by providing a hone comprising ceramic that has a high fusing property, and is solid, of high purity, fine and dense, and opaque.
CONSTITUTION: Particulate aluminum oxide of 83% or more having an irregular particulate size is combined with magnesium oxide to form a uniform mixture. This mixture is molded into long blocks 27, 28 provided with a long and flat surface 33 and a round edge part 31, 32 having a radius R of about 1/32-3/32 inch (about 0.79-2.4 mm). The blocks 27, 28 are heated at temperature of about 1450-1750 to fuse particulates of aluminum oxide. The flat surface 33 and the round edge part 31, 32 are polished to form a polished surface in exposed aluminum oxide particulates in the flat surface 33 and the round edge part 31, 32. At intersection parts of the polished surface of the particulates with side surfaces, cutting edges for polishing a curved cutting edge surface of a curette are formed in the respective particulates.
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