Shika zairyo, kikai = Journal of the Japanese Society for Dental Materials and Devices最新文献_第9页

[Studies on titanium casting. (1) Influence of the mold temperature on titanium castings]. 钛铸件的研究。(1)模具温度对钛合金铸件的影响[j]。

Shika zairyo, kikai = Journal of the Japanese Society for Dental Materials and Devices Pub Date : 1990-03-01

A Kuroiwa, K Wada, Y Hibino, O Yoshida, Y Kakumoto, H Kouchi, K Nagayama, H Hashimoto

{"title":"[Studies on titanium casting. (1) Influence of the mold temperature on titanium castings].","authors":"A Kuroiwa, K Wada, Y Hibino, O Yoshida, Y Kakumoto, H Kouchi, K Nagayama, H Hashimoto","doi":"","DOIUrl":"","url":null,"abstract":"Pure titanium and titanium alloys have excellent biocompatibility, excellent corrosion tarnish resistance, a quarter of the specific gravity of gold base alloys and suitable mechanical properties for dental clinical use. However, titanium has some undesirable characteristics. For example, it has a high melting temperature and chemical reactivity at high temperatures. The investigate influence of the mold temperature on castability and mechanical properties of the titanium castings was study. The castability was found to be good at various mold temperatures, but the higher the mold temperature during casting, the greater the adhesive phenomenon between titanium surface and the investment. From the EPMA observation of the surface layer on the titanium castings, an Si- rich layer whose thickness increased considerably with increasing temperature was observed. The Vickers hardness in the surface layer was greater than that in the inner part. At a higher mold temperature during casting the thickness of the high Vickers hardness layer was increased. There was a relationship between the Vickers hardness value and the thickness of Si rich layer. In the tensile strength test of titanium castings, elongation values decrease and tensile strength values increased with the rise in mold temperature.","PeriodicalId":77622,"journal":{"name":"Shika zairyo, kikai = Journal of the Japanese Society for Dental Materials and Devices","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1990-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"13289573","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}

引用次数: 0

[In vivo wear test for posterior composites. 1. Development of wear test predicting composite wear in vivo]. 后置复合材料的体内磨损试验。1. 预测复合材料体内磨损的磨损试验研究进展[j]。

Shika zairyo, kikai = Journal of the Japanese Society for Dental Materials and Devices Pub Date : 1990-03-01

K Horie, M Satoh, H Kawakita, H Hosoda

引用次数: 0

[Three dimensional shape measurement of teeth. (5) On the measurement by the newly developed double sensor laser displacement meter]. 牙齿的三维形状测量。(5)关于新研制的双传感器激光位移仪的测量。

Shika zairyo, kikai = Journal of the Japanese Society for Dental Materials and Devices Pub Date : 1990-03-01

H Kimura, T Sohmura, T Watanabe

{"title":"[Three dimensional shape measurement of teeth. (5) On the measurement by the newly developed double sensor laser displacement meter].","authors":"H Kimura, T Sohmura, T Watanabe","doi":"","DOIUrl":"","url":null,"abstract":"A laser displacement meter equipped with two PSD (Position Sensitive Device) sensors located 45 symmetrical to the incident beam was developed to measure the three dimensional shape of a tooth with a higher efficiency and accuracy. This displacement meter enabled compensation of the data at the shaded points without the rotational measurement which could not be done by the former single sensor displacement meter. The output voltages on the declined plane measured by the two sensors were different on the complicatedly declined plane. in such a case, the output measured by the sensor which made a larger angle with the declined plane was adopted since it was affected less by the secondary scattering. All regions of the 6 molar were measured without errors, and the cusps and fissures of the occlusal plane were measured as precisely as by the single sensor displacement meter. The time required for the measurement was about 10 min, which was one third that required for the former single sensor displacement meter. For measurement of a crown abutment tooth with steeply inclined slope and margin, by the single sensor displacement meter, the tooth area had to divided into four parts by tilting and rotation on the gonio stage, and required about one and half hours. However, with the present displacement meter, only the measurements with tilting were required and the time was reduced to about 40 min. Besides, the data connection for CG was accomplished in about 5 min, and the complete data without errors and overlap could be saved. This data will be able to give the inner shape of a crown for machining by CAM technique. As mentioned, the newly developed double sensor laser displacement meter greatly simplified the procedure to measure the shape of a tooth and enabled measurements with high precision.","PeriodicalId":77622,"journal":{"name":"Shika zairyo, kikai = Journal of the Japanese Society for Dental Materials and Devices","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1990-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"13289575","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}

引用次数: 0

[Effects of addition of calcium phosphates on the properties of gypsum]. [磷酸钙对石膏性能的影响]。

Shika zairyo, kikai = Journal of the Japanese Society for Dental Materials and Devices Pub Date : 1990-03-01

K Inomata

{"title":"[Effects of addition of calcium phosphates on the properties of gypsum].","authors":"K Inomata","doi":"","DOIUrl":"","url":null,"abstract":"Calcium hydrogen phosphate (CHP), calcium hydrogen phosphate dihydrate (CHPD) and calcium sulfate dihydrate (gypsum) crystals were added to calcium sulfate hemihydrate as gypsum model materials for improvement of the mechanical properties. The compressive and the bending strength of the hardened mixture were improved by the addition of CHPD, while the addition of CHP and gypsum crystals had no effect. The setting time was markedly reduced by the addition of CHPD, but remarkably increased in the case of CHP crystals. On the other hand, the setting expansion was decreased by the addition of CHP and CHPD crystals. Based on the observation of the surface profile of the calcium sulfate hemihydrate set in contact with glass, and scanning electron microscopy (SEM) of the fractured surface of the hardened mixture, the surface roughness was markedly decreased by the addition of CHPD. When the crystals were added to the metastable solution of calcium sulfate supersaturated with respect to gypsum, the presence of gypsum crystals deposited on the CHPD surface was confirmed by atomic absorption analysis, fourier transform infrared spectroscopy. SEM and electron X-ray microanalysis. Therefore, epitaxial growth of gypsum occurred on the CHPD surface and the addition of CHPD improved the mechanical properties of the gypsum materials.","PeriodicalId":77622,"journal":{"name":"Shika zairyo, kikai = Journal of the Japanese Society for Dental Materials and Devices","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1990-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"13290464","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}

引用次数: 0

[In vitro cytotoxicity of denture adhesives]. 义齿黏合剂的体外细胞毒性研究。

Shika zairyo, kikai = Journal of the Japanese Society for Dental Materials and Devices Pub Date : 1990-03-01

H Kakiuchi, K Imai

{"title":"[In vitro cytotoxicity of denture adhesives].","authors":"H Kakiuchi, K Imai","doi":"","DOIUrl":"","url":null,"abstract":"Cell recovery from damage induced by four types of commercial denture adhesives (three powder types, three rubber types, two cream types and one tape type) was studied in vitro, using 3 tissue culture cell lines (L-929 cells, HEp-2 cells and Gin-1 cells). After cultivation with a denture adhesive for two hours, the cells were transferred to a normal culture environment, and their growth was evaluated. Two cytotoxicity tests, i.e., agar overlay test and extraction method, were also carried out. The pH value of the extract was moderately acidic in one powder type (Faston). By contrast, the extracts of the other types were in the neutral range. Cell recovery hardly occurred in the rubber type adhesives and, moderate in the powder types. Slight recovery was noted with the cream types and the tape type. The results of the agar overlay test and the extraction method differed from those of the cell recovery test. The powder type showed marked inhibition of cell growth. The effects of other specimens decreased in the tape type, cream types and rubber types. In the extraction method, the extracts obtained from each specimen did not affect cell growth. Among the cells used, Gin-1 cells showed a slightly higher rate of cell recovery. The discrepancy among the results obtained by the different methods was considered to be due to the state of the specimen and differences in testing conditions. This indicates the importance of selecting an appropriate testing method.","PeriodicalId":77622,"journal":{"name":"Shika zairyo, kikai = Journal of the Japanese Society for Dental Materials and Devices","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1990-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"13290466","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}

引用次数: 0

[Weibull statistical analysis of bending strength data measured either in air or in distilled water for sintered hydroxyapatite ceramics coated on the metal substrate]. [在空气或蒸馏水中对涂覆在金属基体上的烧结羟基磷灰石陶瓷的弯曲强度数据进行威布尔统计分析]。

Shika zairyo, kikai = Journal of the Japanese Society for Dental Materials and Devices Pub Date : 1990-03-01

N Wakamatsu, T Goto, M Adachi, S Imura, K Hayashi, H Kamemizu, M Iijima, T Gyotoku, S Shibata, T Horiguchi

{"title":"[Weibull statistical analysis of bending strength data measured either in air or in distilled water for sintered hydroxyapatite ceramics coated on the metal substrate].","authors":"N Wakamatsu, T Goto, M Adachi, S Imura, K Hayashi, H Kamemizu, M Iijima, T Gyotoku, S Shibata, T Horiguchi","doi":"","DOIUrl":"","url":null,"abstract":"To assess the effects of H2O on the fracture stress of sintered hydroxyapatite (HAP) ceramics prepared by procedures similar to those used for HAP coated on the metal substrate, four-point bending tests were carried out at 0.5 mm/min either in air (20 C, R.H. 73%) or in distilled water (37 degrees C). Then, strength data obtained were analyzed using two-parameter weibull statistics. In each condition, the bending strength data gave a good fit to single-mode weibull distribution. Weibull analysis of the data gave weibull parameter m = 7.8, sigma 0 = 26.2 MPa in air and m = 8.1, sigma 0 = 18.5 MPa in distilled water, which were calculated assuming a surface flaw model. The mean value of bending strength was 27.3 MPa in air and 18.2 MPa in distilled water. These results indicated that a corrosive environment such as H2O affects fracture stress when measured at a constant stress rate. This effect is considered to be caused by slow crack growth of cracks, occurring at a loading level lower than those at which specimens will fail. Using the weibull distribution function estimated in this study, the effects of both dimension of specimen and stress distribution in the specimen on the mean fracture stress have been predicted.","PeriodicalId":77622,"journal":{"name":"Shika zairyo, kikai = Journal of the Japanese Society for Dental Materials and Devices","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1990-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"13290468","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}

引用次数: 0

[Corrosion of dental titanium alloys binary system of Ti-Al, Ti-Cu, Ti-Ni]. [牙科钛合金Ti-Al, Ti-Cu, Ti-Ni二元体系的腐蚀]。

Shika zairyo, kikai = Journal of the Japanese Society for Dental Materials and Devices Pub Date : 1990-03-01

Y Oda, M Funasaka, T Sumii

引用次数: 0

[Study on adhesion mechanism of MMA-TBBO resin to dentin. A model experiment using decalcified dentin]. MMA-TBBO树脂与牙本质黏附机理研究。脱钙牙本质模型实验[j]。

Shika zairyo, kikai = Journal of the Japanese Society for Dental Materials and Devices Pub Date : 1990-03-01

T Akimoto, Y Kadoma, Y Imai

引用次数: 0

[Bending behavior of superplastic titanium alloy for denture base]. [超塑性钛合金义齿基托弯曲性能研究]。

Shika zairyo, kikai = Journal of the Japanese Society for Dental Materials and Devices Pub Date : 1990-03-01

N Wakabayashi, M Ai, O Okuno

引用次数: 0

[Crystalline glass ceramics model teeth]. [结晶玻璃陶瓷模型牙齿]。

Shika zairyo, kikai = Journal of the Japanese Society for Dental Materials and Devices Pub Date : 1990-03-01

K Nagayama, Y Hibino, A Kuroiwa, S Kiyota, K Wada, N Tomioka, H Hashimoto

引用次数: 0