Abstract: An oral cavity spreading apparatus. The apparatus includes a pair of mouth corner hooks capable of being inserted into the oral cavity to spread the corners of the mouth, wing portions protruding individually outward from the mouth corner hooks and capable of spreading the inner part of the oral cavity, and a substantially U-shaped spring arm portion connecting the mouth corner hooks. The mouth corner hooks are adapted to be pressed toward each other against the urging force of the spring arm portion so that the respective end portions of the mouth corner hooks engage each other and the wing portions are steadily rotated inward and toward each other around the point of engagement between the end portions as a pivot as the mouth corner hooks are inserted into the oral cavity.

Abstract: An oral cavity spreading apparatus according to the present invention comprises a pair of mouth corner hooks capable of being inserted into the oral cavity to spread the corners of the mouth, wing portions protruding individually outward from the mouth corner hooks and capable of spreading the inner part of the oral cavity, and a substantially U-shaped spring arm portion connecting the mouth corner hooks, the mouth corner hooks being adapted to be pressed toward each other against the urging force of the spring arm portion so that the respective end portions of the mouth corner hooks engage each other and the wing portions are steadily rotated inward and toward each other around the point of engagement between the end portions as a pivot as the mouth corner hooks are inserted into the oral cavity.

Abstract: There is disclosed a dental caries-removing material consisting of grinding granules ejected against dental caries, or pathological issues, to remove them. The granules are obtained by pulverizing untoxic stones of seeds and have Vickers hardness values (JIS Z 1051)(Hv) of 10 to 60 and granular diameters of 40 to 160 .mu.m. This material is prepared by pulverizing and grading stones of seeds (such as peach, plum, apricot, or Japanese apricot).

Abstract: The invention relates to the improvement of plaque remover consisting of an abradant for removing dental plaque, dirt adhered to teeth, dirt adhered to filler, dirt adhered to prosthesis or dirt adhered to implant by injecting it with water or with water and compressed air. By using granular polysaccharide as the plaque remover derived from natural materials such as cellulose, starch, agar, pulverized particles of a fibrous plant body, particles prepared by decomposing a fibrous plant body, plaque can be removed without damaging not only sound enamel but also dentin prosthesis filler, gingiva and stomal membrane.