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

{"title":"[The effect of eugenol cement, CC, FC on the bonding strength of the adhesive resin to the tooth surface (author's transl)].","authors":"P I Chang,&nbsp;H E Lee,&nbsp;E Masuhara","doi":"","DOIUrl":"","url":null,"abstract":"<p><p>Bovine tooth surface pretreated with dental medicaments-Eugenol cement (ZOE), CC, FC was used to adhere to acrylic rod by adhesive resins-Clearfil F II and 4 META-MMA-TBB-O. The effects of the dental medicaments on the bonding strength of the adhesive resin were measured. The results were showed as follows: (1) Any pretreatment of the three medicaments reduced the bonding strength of Clearfil to both enamel and dentin surface. With 4-META-MMA-TBB-O resin system the bonding strength was reduced by ZOE and CC while it was increased by FC pretreatment. (2) On the enamel tooth surface premedicated with ZOE, FC or CC, the alcohol rinsing or mechanic grinding reduced the decrease of the bonding strength of Clearfil. With 4-META-MMA-TBB-O resin, the mechanic grinding of the premedicated enamel tooth surface increased the bonding strength. (3) On the premedicated dentin tooth surface, the mechanic grinding reduced the decrease of the bonding strength of 4-META-MMA-TBB-O. Alcohol rinsing, on the contrary, decreased the bonding strength. (4) On both fresh and premedicated dentin surface the bonding strength of Clearfil was lower than 3 MPa.</p>","PeriodicalId":76541,"journal":{"name":"Shika rikogaku zasshi. Journal of the Japan Society for Dental Apparatus and Materials","volume":"23 61","pages":"93-7"},"PeriodicalIF":0.0,"publicationDate":"1982-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"18090353","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 performance of the dental air turbine handpieces. (Part 6) Investigation on the power of several air turbine handpieces (N = No-CvEv gamma) (author's transl)].","authors":"H Miyairi,&nbsp;M Nagai,&nbsp;H Fukuda,&nbsp;A Muramatsu","doi":"","DOIUrl":"","url":null,"abstract":"<p><p>We have examined the basic studies on the rotational performance of the air turbine handpieces by using the brake method. Once, we used the constant feed speed testing method in which the test bur was pressed to the brake block at a constant feed speed. In the case of this method, the load increases in inverse proportion to the rotational speed as the loading time increases. In this paper for analyzing on the problem of the brake block materials used to this testing method, we did the performance test of the usually used air turbine handpieces by using the glass and the supper alloy which were superior to the frictional resistance as the brake materials. Consequently, by the difference of these brake materials, the characteristics of handpieces are not influences. But, in the long loading times, the dynamic friction coefficient between the glass block and the test bur became the great values. Therefore, in the constant feed speed testing method, the measured values of normal loads on the test bur, are influenced with the dynamic friction coefficients in the high load levels. On the rapidly dropped phenomenon of the rotational speed of air turbine handpieces, we measured the moment values at the support of test bur. And then we discussed the relation between the rotational performance and the length of burs or points using for cutting instruments. On the basis of the theoretical and experimental investigations of air turbine's rotational performance, we measured and examined the maximum works of the various kinds of the handpieces used in clinical field. The characteristics of the four-type handpieces, such the standard, torque and miniature types and air bearing type, used in this studies, were influenced with the materials of the brake block as far as the bounds of the loads were high in the rotational performance tests.</p>","PeriodicalId":76541,"journal":{"name":"Shika rikogaku zasshi. Journal of the Japan Society for Dental Apparatus and Materials","volume":"23 61","pages":"58-64"},"PeriodicalIF":0.0,"publicationDate":"1982-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"18090350","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":"[Aluminous cement for dental application (author's transl)].","authors":"S Takeda","doi":"","DOIUrl":"","url":null,"abstract":"<p><p>The various materials such as zinc oxide eugenol pastes, calcium hydroxide slurry and self hardening polymers have been used for the root canal filling and pulp capping. However, those materials have various problems in terms of biocompatibility and physical properties in clinical use. The development of root canal filling and pulp capping materials has been carried out with powder-liquid system which consisted of aluminous cement added to 20 wt% Ca (OH)2 and polyvinylalcohol solutions. The influence of polyvinylalcohol concentrations and L/P ratio on physical properties and biocompatibility were investigated. The results were as follows: 1. The initial setting time was showed between 3 and 20 minutes according to polyvinylalcohol concentration and L/P ratio and delayed linearly by increasing the L/P ratio. 2. The consistency was indicated between 18 and 51 mm with polyvinylalcohol concentration and L/P ratio. The lower the L/P ratio, the thicker was the consistency. 3. The solubilities in distilled water were 2.7-7.3% and 3.9-8.4%, respectively, after storage for 24 hours and 1 week, while those values in 199 medium were 2.9-6.2% and 4.4-9.9%, respectively, after storage for 24 hours and 1 week. 4. The pH values in distilled water were indicated high alkaline conditions of about 11.5 after storage for 24 hours and was not influenced by the repeated immersions. On the other hand, the pH values in 199 medium were showed high alkaline conditions of about 11.0 after storage for 24 hours, but decreased rapidly to the neutral conditions of about 8.0 with the repeated immersion. 5. The compressive strengths were increased by the use of higher polyvinylalcohol concentration and lower L/P ratio and indicated from 26 kg/cm2 and 278 kg/cm2. 6. By the use of the tissue culture method, mild response with the un-set cement was recognized from the morphological observation. In the case of the set cement, the cell morphological changes showed no significant difference in the cytotoxicity compared with that of control culture. The disappearance of the cytotoxicity was recognized in according to the progress of setting process.</p>","PeriodicalId":76541,"journal":{"name":"Shika rikogaku zasshi. Journal of the Japan Society for Dental Apparatus and Materials","volume":"23 61","pages":"76-87"},"PeriodicalIF":0.0,"publicationDate":"1982-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"17999628","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":"Microstructure change and segregation distribution in dental 32 Ni-23 Cu-25 Mn casting alloy. (Part II) Effect of chill-metal system.","authors":"K Wakasa,&nbsp;M Yamaki","doi":"","DOIUrl":"","url":null,"abstract":"<p><p>When chill-metal was used to disk-like casting specimens in low-melting Ni-Cu-Mn alloy, the following results were obtained in comparison with air-vent system: dendritic A-grain changed spherically, and the amount of B-grain increased. In case of grain-size distribution, C-grain changed to a very small-scale, but the others (A- and B-grains) showed the same change as air-vent system. In addition, the segregation distribution of Ni, Cu, Mn, Cr and Ge in individual grains was found, similarly to air-vent system.</p>","PeriodicalId":76541,"journal":{"name":"Shika rikogaku zasshi. Journal of the Japan Society for Dental Apparatus and Materials","volume":"23 61","pages":"24-8"},"PeriodicalIF":0.0,"publicationDate":"1982-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"18089558","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 dental self-curing resins (19) - adhesion of 4-META/MMA-TBB resin to pretreated dentine (author's transl)].","authors":"N Nakabayashi,&nbsp;M Takeyama,&nbsp;K Kojima,&nbsp;E Masuhara","doi":"","DOIUrl":"","url":null,"abstract":"<p><p>A new 4-META/MMA-TBB adhesive resin has been studied and the effectiveness on adhesion to tooth substrates and dental alloys was reported previously. Here we are showing affection of cleaner or etchants on the adhesion between dentines and the 4-META/MMA-TBB resin. The adhesive strength becomes superior, 18 MPa, when dentines have been cleaned with a 10% citric acid-3% ferric chloride solution. On the other hand an etchant, phosphoric acid or citric acid alone, is not so effective as the mixed solution and the strength decreases to 6 MPa. Scanning electron microscopic study on pretreated dentine with several solutions is also carried out and it is found that debris on dentine should be removed but that in tubules is not necessary to be cleaned up to get good adhesion.</p>","PeriodicalId":76541,"journal":{"name":"Shika rikogaku zasshi. Journal of the Japan Society for Dental Apparatus and Materials","volume":"23 61","pages":"29-33"},"PeriodicalIF":0.0,"publicationDate":"1982-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"18089559","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":"[Study of nickel-chromium alloys containing titanium for porcelain bonding (author's transl)].","authors":"Y Hirose","doi":"","DOIUrl":"","url":null,"abstract":"<p><p>In order to analyze the effects of titanium and chromium and to determine the best composition of nickel-chromium alloys containing titanium for porcelain bonding, the mechanical properties, the tarnish resistance, and the porcelain bond strength of each of sixteen experimental alloys which were composed of nickel (54 to 90 wt%), chromium (10 to 40 wt%), titanium (0 to 6 wt%) were studied. The values of tensile strength, proportional limit, and Vickers hardness number for the alloys ranged from 33.4 to 68.1 kgf/mm2, 9.2 to 67.6 kgf/mm2, and 109 to 504 respectively. The increasing amount of titanium and/or chromium tended to the increase of those values. The elongation was higher than 24% for the alloys containing no titanium, but decreased to 0.3% with the increase of titanium and/or chromium content. The tarnish resistance for the alloys which contained only 10% chromium was not good. The porcelain bond strength of the alloys increased very significantly as the titanium content and/or the chromium content increased. In this study, the compositions of 58 to 76% Ni - 20 to 40%Cr - 2 to 4%Ti were considered to be optimum for porcelain bonding.</p>","PeriodicalId":76541,"journal":{"name":"Shika rikogaku zasshi. Journal of the Japan Society for Dental Apparatus and Materials","volume":"23 61","pages":"98-115"},"PeriodicalIF":0.0,"publicationDate":"1982-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"18090354","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 mechanical properties of dental Ag-Pd-Au-Cu alloys. (Part 1) Effects of age-hardening treatment on the tensile behaviour of alloys (author's transl)].","authors":"K Asaoka,&nbsp;K Tsuji,&nbsp;N Kuwayama","doi":"","DOIUrl":"","url":null,"abstract":"<p><p>Tensile behaviour of Ag-Pd-Au-Cu alloys depending on age-hardening was studied by the tensile test with extensometer. The fractured surface of the alloys was observed by the scanning electron microscope. Plastic deformation of alloys was changed from discontinuous yielding to parabolic strain hardening, as the size of precipitate hard particles was grown by aging. There appears to be good correlation between the tensile strength of alloys with aging and the hardness. Strain hardening parameters of the Ludwik, Swift, Voce and Hollomon empirical equations in describing the stress-strain curves were calculated by the least square method. Theoretical tensile strength which was computed from these empirical equations, was good agreement with the tensile test of alloys with aging. But, theoretical uniform elongation tended to elongate. The ratio of tensile strength to proof stress of over-aged alloys was extremely low, as compared with the other alloys. So, over-aging should be avoided to use the alloys in dentistry. If structure of the precipitate particles is controlled by aging temperature and time, the loss of ductility on age-hardening will be considerably eliminated.</p>","PeriodicalId":76541,"journal":{"name":"Shika rikogaku zasshi. Journal of the Japan Society for Dental Apparatus and Materials","volume":"22 60","pages":"271-6"},"PeriodicalIF":0.0,"publicationDate":"1981-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"17999924","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":"Porosity--strength relationship in a Cu-rich spherical alloy amalgam.","authors":"J R Mackert,&nbsp;M Adachi,&nbsp;T Goto,&nbsp;H Otani","doi":"","DOIUrl":"","url":null,"abstract":"<p><p>Porosity and strength of spherical Cu-rich alloy amalgams were analyzed in the under-graduate materials laboratory. The minimum value for porosity was obtained for 46% initial Hg content, whereas the maximum strengths were obtained for 42% initial Hg. This result did not coincide with the data previously obtained for the conventional spherical alloy amalgam, in which the maximum strength and the minimum porosity were strictly associated with the optimum initial Hg content. Although no critical value for porosity could be definitely demonstrated by this effort, this result may be an indirect indication for 4.5 vol% porosity as the critical value.</p>","PeriodicalId":76541,"journal":{"name":"Shika rikogaku zasshi. Journal of the Japan Society for Dental Apparatus and Materials","volume":"22 60","pages":"257-61"},"PeriodicalIF":0.0,"publicationDate":"1981-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"17999922","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":"[Japanese and foreign literature on dental apparatus and materials, XXII. 1980].","authors":"","doi":"","DOIUrl":"","url":null,"abstract":"","PeriodicalId":76541,"journal":{"name":"Shika rikogaku zasshi. Journal of the Japan Society for Dental Apparatus and Materials","volume":"22 60","pages":"323-57"},"PeriodicalIF":0.0,"publicationDate":"1981-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"18084976","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":"[Cast fractures of dental Ni-Cr alloys (author's transl)].","authors":"J Takahashi,&nbsp;S Kaneda,&nbsp;M Okazaki,&nbsp;Y Doi,&nbsp;Y Moriwaki,&nbsp;H Kimura","doi":"","DOIUrl":"","url":null,"abstract":"<p><p>Cast fractures of Ni-Cr alloys were investigated by means of scanning electron microscopy, energy dispersive X-ray spectrometry, electron-probe microanalysis, density measurements, setting and thermal expansion measurements and compressive tests. Three-Ni-Cr alloys for crowns and bridges were cast in spiral configurations by an argon-arc pressured type or an induction argon-pressured type-casting machine. The amount of cast fracture increase with an increase in cast temperature, but not with an increase of holding time at cast temperature. Ni-Cr alloys have more cast fractures in a phosphate-bonded investment than in a gypsum-bonded cristobalite investment. Fracture surfaces have an exposed dendrite structure, indicating the presence of cast porosity. The trigger of cast crack can be a cast porosity and the propagation of crack to fracture may be mainly due to the strength of investments.</p>","PeriodicalId":76541,"journal":{"name":"Shika rikogaku zasshi. Journal of the Japan Society for Dental Apparatus and Materials","volume":"22 60","pages":"306-14"},"PeriodicalIF":0.0,"publicationDate":"1981-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"18084977","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}