Shika rikogaku zasshi. Journal of the Japan Society for Dental Apparatus and Materials最新文献

{"title":"[Retention of three different luting cements (author's transl)].","authors":"T Goto,&nbsp;M Adachi,&nbsp;Y Otani","doi":"","DOIUrl":"","url":null,"abstract":"<p><p>Employing zinc phosphate, polycarboxylate and glass ionomer cements, effect of cement layer thickness on retention of crowns at their axial wall was investigated. Stainless steel preparations and occlusally perforated crowns having taper angles of 2.9 and 5.7 degrees were cemented, regulating the thickness at the axial wall from 5 to 60 mu. These dies were stored in a 100% relative humidity atmosphere at room temperature or in distilled water. After 48 hr, retention was measured, applying the load vertically to occlusal preparation surface through a plunger (Fig. 1). Due to the inclusion of unreacted powder particles in the set structure of all three cements, evidence of a critical value was always shown in the cement thickness-retention relationship (Figs. 2, 3 and 4). When the cement thickness was reduced below the critical value, the retention increased remarkably and was not affected by the environment. Above the critical value, however, the retention of these cements was relatively small and affected considerably by the environment. By water immersion, the increase in the retention was found for the two polyacrylate, but not for the zinc phosphate. Correlation between retention and mechanical strengths of the three cements in the respective environments was indefinite.</p>","PeriodicalId":76541,"journal":{"name":"Shika rikogaku zasshi. Journal of the Japan Society for Dental Apparatus and Materials","volume":"22 59","pages":"168-71"},"PeriodicalIF":0.0,"publicationDate":"1981-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"18080679","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"[Comparative study on cytotoxicity of main components of three luting cements in vitro (author's transl)].","authors":"K Sogawa","doi":"","DOIUrl":"","url":null,"abstract":"<p><p>In order to elucidate cytotoxicity of main components of glass ionomer, polycarboxylate and zinc phosphate cements, cell culture method was utilized. Criteria of cellular responses were made on the basis of cell growth and changes in cell morphology. The results obtained were as follows: 1. SiO2, AlF3, Al2O3, Ca3(PO4)2 and NaAlF6 of powder components in glass ionomer cement did not yield any unfavourable effects on either cell growth nor morphology. On the other hand, AlPO4 yielded moderate cytotoxic reaction and CaF2 marked reaction. 2. ZnO and MgO of powder components in polycarboxylate and zinc phosphate cements yielded marked cytotoxic reaction. Moreover, CaO of zinc phosphate cement brought very marked cytotoxic reaction. On the other hand, SiO2 and Bi2O3 did not yield any unfavourable effects on either cell growth nor morphology. 3. All the liquids of three cements brought cytotoxic reaction ranging from marked to very marked levels. The present results seemed to reveal that mild cytotoxic reaction of glass ionomer cement, which had been reported, was due to inclusion of less cytotoxic components compared to polycarboxylate or zinc phosphate cements. It was also discussed the relationship between biocompatibility of the cements and dissolution of the components. It is considered that the present results could shed a light on biocompatibility of dental cements.</p>","PeriodicalId":76541,"journal":{"name":"Shika rikogaku zasshi. Journal of the Japan Society for Dental Apparatus and Materials","volume":"22 59","pages":"172-86"},"PeriodicalIF":0.0,"publicationDate":"1981-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"17995283","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"[Studies on the aging characteristics of gold alloys used for metal-ceramics restorations--age-hardening mechanism in a Au-8 wt%Pd-4 wt%In alloy. (Part 2) (author's transl)].","authors":"H Sasaki","doi":"","DOIUrl":"","url":null,"abstract":"<p><p>The age-hardening mechanism in a Au-8wt%Pd ternary alloy containing 4wt+In were investigated by means of electrical resistivity measurement, hardness test, transmission electron microscopy, X-ray microanalysis and diffractions. The following conclusions had been drawn. 1. Two maxima in resistivity appeared during isochronal aging. These changes were also observed during isothermal aging. Each depended on the aging temperature and time, respectively. 2. The first maximum in resistivity was considered to be due to the formation of the short range order clustering promoted by the addition of indium to the gold-palladium binary alloy. 3. The second maximum in resistivity was due to the spinodal decomposition. 4. The rapid decreasing in resistivity during the isochronal or isothermal aging was due to the formation of modulated structures attended by the separation of ordered phases. 5. These precipitates determined by X-ray microdiffraction method were two intermetallic compounds ordered ortho type Pd2In and fct type Pd3In. 6. It was concluded that the mechanism of age-hardening in this alloy was due to the formation of modulated structures being accompanied by the precipitation of Pd2In and Pd3In from the supersaturated solid solution.</p>","PeriodicalId":76541,"journal":{"name":"Shika rikogaku zasshi. Journal of the Japan Society for Dental Apparatus and Materials","volume":"22 59","pages":"222-34"},"PeriodicalIF":0.0,"publicationDate":"1981-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"17995288","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"[Studies on the distortion of the cast crown by measuring volume change (author's transl)].","authors":"H Arikawa,&nbsp;K Jyoshin,&nbsp;S Nakazawa","doi":"","DOIUrl":"","url":null,"abstract":"<p><p>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.</p>","PeriodicalId":76541,"journal":{"name":"Shika rikogaku zasshi. Journal of the Japan Society for Dental Apparatus and Materials","volume":"22 58","pages":"114-8"},"PeriodicalIF":0.0,"publicationDate":"1981-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"18074319","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"[Mechanical properties of microfilled composite resins (author's transl)].","authors":"T Hirasawa,&nbsp;S Hirano,&nbsp;S Hirabayashi,&nbsp;I Harashima,&nbsp;I Nasu,&nbsp;T Kurosawa","doi":"","DOIUrl":"","url":null,"abstract":"<p><p>The various mechanical properties of seven microfilled composite resins were evaluated, comparing with two conventional composite resins. The following results were obtained. 1) Though microfilled composite resins were more excellent than conventional ones on surface roughness after polishing or brushing, but they were inferior to conventional ones on the resistance to brushing abrasion. 2) Tensile, compressive and bending strength were dependent on inorganic filler content and properties of matrix resin. Particularly, their mechanical properties in the wet condition were strongly influenced by whether matrix resin was hydrophilic or hydrophobic. Compared with conventional composite resins, microfilled ones contained 30 to 40 wt% of filler had lower values of tensile and bending strength, and near values of compressive strength. While, microfilled ones contained 50 to 60 wt% of filler had higher values of compressive strength, and near values of tensile and bending strength, compared to conventional ones. 3) Modulus of elasticity and hardness were mainly dependent on inorganic filler content. Moduli of elasticity of microfilled composite resins were about 25 to 33% of them of conventional ones, and hardnesses of microfilled ones were approximately 50% of them of conventional ones except some materials. Hardnesses of microfilled composite resins with 50 to 60 wt% of filler were similar to them of conventional ones.</p>","PeriodicalId":76541,"journal":{"name":"Shika rikogaku zasshi. Journal of the Japan Society for Dental Apparatus and Materials","volume":"22 59","pages":"187-95"},"PeriodicalIF":0.0,"publicationDate":"1981-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"17995284","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"[Measurements of cell adhesion to biomaterials by supersonics (author's transl)].","authors":"T Maeda,&nbsp;H Taguchi,&nbsp;Y Nomura,&nbsp;H Ikeda,&nbsp;T Iseki,&nbsp;M Nakamura,&nbsp;H Kawahara","doi":"","DOIUrl":"","url":null,"abstract":"<p><p>In order to examine eligibility of supersonic vibration energy for investigating cell-material contract, L-strain fibroblasts were cultivated on glass surface and exposed to supersonic vibration. The cells adhered to the glass surface were detached by supersonic vibration and both of adhered cells to the glass surface and detached cells after the supersonic exposure were cultivated for one week. And the cell activity of the detached cells was estimated with cell multiplication by cell nuclei counting and their morphological changes. As a result, use of supersonic vibration energy was found effective in expressing degrees of cell adhesiveness to glass or biomaterials. The most appropriate vibration was decided at 485 KHz in frequency, 5 V in secondary voltage and approximately 30 seconds. It is revealed that the results may be effective in the analysis of cell-biomaterial contact.</p>","PeriodicalId":76541,"journal":{"name":"Shika rikogaku zasshi. Journal of the Japan Society for Dental Apparatus and Materials","volume":"22 59","pages":"162-7"},"PeriodicalIF":0.0,"publicationDate":"1981-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"17995282","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"[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)].","authors":"K Jyoshin,&nbsp;H Arikawa","doi":"","DOIUrl":"","url":null,"abstract":"<p><p>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-.</p>","PeriodicalId":76541,"journal":{"name":"Shika rikogaku zasshi. Journal of the Japan Society for Dental Apparatus and Materials","volume":"22 59","pages":"213-6"},"PeriodicalIF":0.0,"publicationDate":"1981-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"17995286","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"[Aging effect on mechanical properties in fluid resin. (Part 3) Affection of residual monomer on the surface morphology after tensile test by microscopic observation (author's transl)].","authors":"A Horiuchi","doi":"","DOIUrl":"","url":null,"abstract":"<p><p>Affection of residual monomer on the surface morphology after tensile test was observed by an scanning microscope. Evaporation or leaching of the monomer gave big influence on the morphology of pearls and matrix. The observation suggested that the residual monomer existed mainly in the matrix. When the residual monomer disappeared, the surface morphology did not change by tensile load. It is the most important point to get good denture with fluid resin that we could decrease the residual monomer as possible.</p>","PeriodicalId":76541,"journal":{"name":"Shika rikogaku zasshi. Journal of the Japan Society for Dental Apparatus and Materials","volume":"22 58","pages":"147-52"},"PeriodicalIF":0.0,"publicationDate":"1981-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"17995463","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"[Isothermal ordering process and order-hardening in CuPd alloys (author's transl)].","authors":"T Shiraishi","doi":"","DOIUrl":"","url":null,"abstract":"<p><p>The isothermal ordering process in CuPd alloys containing 34.74 approximately 50.22 at % Pd was investigated by means of electrical resistivity measurements, X-ray diffraction, metallographic observations and hardness tests. The ordering mechanism and the order-hardening mechanism were discussed. Ordering in the alloys which are in the region of beta (ordered) single phase in equilibrium phase diagram, apparently occurred through single process, and the ordering rate was very high. On the other hand, ordering occurred through two processes (stage I and II) in the case of the alloys in which ordered and disordered phases, i.e. beta and alpha phases coexist, and the ordering rate was low. Ordering was attained by discontinuous ordering mechanism in both regions. Considering the value of activation energy for ordering and results of metallographic observations, it is suggested that the ordering is attained by grain boundary diffusion both in the beta single phase region and in stage II of the (alpha + beta) two phased region. It can be also interpreted that the order-hardening in these alloys is attributed to the increase of volume fraction of beta phase in both regions.</p>","PeriodicalId":76541,"journal":{"name":"Shika rikogaku zasshi. Journal of the Japan Society for Dental Apparatus and Materials","volume":"22 58","pages":"119-28"},"PeriodicalIF":0.0,"publicationDate":"1981-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"17995615","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"[Studies on the accuracy of the castings. (Part 10) On the effects of starting time of the heat to phosphate bonded investment mold (author's transl)].","authors":"M Ito,&nbsp;S Nagasawa,&nbsp;T Miyazawa","doi":"","DOIUrl":"","url":null,"abstract":"<p><p>Properties of phosphate bonded investments are superior than that of plaster bonded investments in mechanical properties, expansional values for compensating to the casting shrinkage of alloys, and refractory resistance. Therefore, phosphate bonded investments have been available to casting for high fusing alloys. But, their properties are varied easily by manipulating. In this report, two commercial products of Cerami Gold (Whip--Mix Corp.) and Ceravest (G--C Dental Industrial Corp.) were used. They were studied on setting expansion, thermal expansion, compressive strength, change of pH value caused by setting reaction, decrement of weight, casting accuracy and roughness of castings in process of time. Results were follows; 1. The weight decrement of investment mold were about 1.5% on Cerami Gold and 3.5% on Ceravest at 24 hours after the mold had been prepared. 2. pH value of Cerami Gold investment mold changed to 8.5 from 7.0 at 5 hours after mixing, but that of Ceravest investment mold changed to 9.0 from 7.0 at 3 hours. 3. The setting expansion of Cerami Gold investment was caused about 0.9% at 3 hours and that of Ceravest investment was about 0.3% at 1 hour ater mixing. Since then, they were to be constant. 4. The thermal expansion of Cerami Gold investment was decreased by elapsed time until 3 hours after mixing, and then since passing at 5 hours, they were increased. But, that of Ceravest investment was decreased in process of time. 5. The compressive strength of both investments were increased as long as elapsed time after setting. Heating at 800 degrees C in the oven, it was 100--110 Kg/cm2 regardless of time on Ceravest investment, and other was 170 kg/cm2 which was increased until passing 5 hours. 6. The roughness of castings surface were similar to the mold surface and they were H3 12--16 microns which were decreased as elapsed time after investment was mixed. 7. Accurate castings were produced by the mold heated after 24 hours, using with Cerami Gold investment. On the Ceravest investment, it was 30 minutes of 5 hours after mixing.</p>","PeriodicalId":76541,"journal":{"name":"Shika rikogaku zasshi. Journal of the Japan Society for Dental Apparatus and Materials","volume":"22 59","pages":"202-12"},"PeriodicalIF":0.0,"publicationDate":"1981-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"18080680","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}