Abstract
The use of acrylic resin teeth in dentures to replace the usual porcelain teeth has gained considerable favor during recent years in Japan.
But very little is known about the physical characteristics of the resin teeth produced in our country, so we have studied about their properties with other countries products.
1) The composition of resin teeth are essentially polymethylmethacrylate, but some of teeth contain a cross-linking agent (sample 1, 7, 8) .
2) The construction of resin teeth were consider in view of the sagittal section of resin teeth (Photo 1) . Many of the teeth were processed by the powder-liquid method, and some were processed by an industrial injection molding process (sample 2, 4) .
3) The knoop hardness number of resin teeth are about 17-18 except the sample 5 of K. H-N. 19.
The abrasion resistance of the resin teeth are measured by mean of a dropped carbolundum method, and it is estimated that he wear down amount by the dropped carbolundum on resin teeth surface are approximately treble amount of polyurethan teeth (sample 11) .
The result of experiments it found that the resin teeth on the market exhibit desirable physical properties as a polymethylmethacrylic resin teeth, but the aim of artificial plastic teeth must be to improve the hardness and abrasive resistance by the application of new plastic materials.
