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K Jyoshin

Publications and source records attributed to K Jyoshin.

7 recordsLinked to original sources
PubMed1981

[Studies on the setting reaction of the zinc phosphate dental cement (3)--quantitative analysis for consumed zinc oxide through setting reaction of the cement (author's transl)].

Zinc oxide powder of zinc phosphate cement for dental use was mixed with various phosphoric acid for cement liquid contained Al3+ and not, and zinc oxide in each cement after setting was determined quantitatively Then, consumed zinc oxide through setting reaction was calculated. When zinc oxide powder was mixed with cement liquid contained Al3+, consumed zinc oxide through setting reaction was approximate half quantity of it mixed with liquid contained no Al3+. This result show that setting reaction of zinc phosphate dental cement is the interaction Al3+ and H2PO4- in cement liquid rather than simple neutralizing reaction, ZnO+H3PO4 or ZnO+H2PO4-.

Aluminum↗
PubMed1981

[Studies on the distortion of the cast crown by measuring volume change (author's transl)].

We made experimental cast crowns under various casting conditions, and measured their dimensional change of inner cervical margin and volume change compared with wax patterns. The relation between percentage of linear expansion (alpha) and percentage of cubic expansion (beta) of matter is beta not equal to 3alpha. When investment mold and cast metal equally expand or contract in all direction, the relation between the dimensional change (=alpha) and the volume change (=beta) of the cast crown must obey this expression beta not equal to 3alpha. When the relation between alpha and beta of the cast crown is not beta not equal to 3alpha, we consider the cast has distortion. Casting conditions were fifteen kinds by changing investment, casting method, linning material and mold temperature. The following results were obtained. 1) Placing wet asbestos liner, dimension was larger than its pattern. But, contraction of volume was great. 2) Placing kaowool liner and asbestos liner coated with vaseline contraction of volume was improved. 3) In case of ringless casting method, the cast crown gave best fit to metal die, and distortion was very small. 4) Judging from these results, hygroscopic expansion of investment by wet asbestos liner made volume contracts, and made the cast crown distort. 5) In case of casting at low temperature ceravest mold (150 degree C), dimension was as large as casting at high temperature mold (700 degree C). But, the lower the mold temperature, the larger the contraction of volume. Therefore, the cast crown fitted metal die, but had large distortion.

Crowns↗
PubMed1980

[Study on the setting reaction of the zinc phosphate dental cement (1). Effects of aluminum in liquid on setting reaction (author's transl)].

The liquid of zinc phosphate dental cement contains Al3+ and Zn2+, and these ions effect greatly on the setting reaction of the cement. When zinc oxide powder is mixed with this cement liquid, reaction products in the set cement are amorphous and not made sure by X-ray diffraction. Therefore the setting reaction of zinc phosphate cement is not certain. In this paper the effects of Al3+ on the setting reaction of cement are examined by X-ray diffraction, thermal analysis and infrared spectrum, and set cements are observed by SEM and microradiography. Judging from these results, it is conclude that Al3+ in the cement liquid precipitates amorphous aluminium phosphate due to change of pH of liquid when it is mixed with zinc oxide powder.

Aluminum↗
PubMed1980

[Study on the setting reaction of the zinc phosphate dental cement (2). The setting reaction of cement substituted magnesia clinker for zinc oxide (author's transl)].

In previous paper it has been reported by author that setting of the zinc phosphate cement is due to precipitation of amorphous aluminium phosphate rather than zinc phosphate. If such the setting reaction on the zinc phosphate cement is right, there is no necessity that cement powder is zinc oxide clinker. In this paper magnesia clinker is substituted for zinc oxide, and the reaction products of set cement are examined by the same methods as having shown in previous paper. When commercial cement liquid is used for mixing with magnesia clinker, the reaction products become amorphous for effects of Al3+ in liquid. These are the same amorphous reaction products as precipitating in set zinc phosphate cement. From result in previous and this paper, it has been made sure that setting reaction of zinc phosphate cement is due to precipitation of amorphous aluminium and zinc (in liquid) phosphate.

Aluminum↗