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床用レジンの臭気に関する研究第2報 食物および温度と,臭気に関する基礎的実験
Get PDFapplication/pdfWe conducted experiments to determine the odor intensity of resin materials for denture bases after immersing and shaking in some foods, drinks and an artificial saliva for twelve months. To measure the odor intensity of these materials we used an odor measuring apparatus, "ALABASTER" (B & H LABO), using a semi-conductor sensor (SnO_2) that can be operated in an ozone based atmosphere. There was no significant difference among the odor concentration values of the denture resins as polymerized pieces after maintaining a constant temperature for thirty minutes each at room temperature (20℃-23℃), 37℃, 60℃, 100℃ and 150℃. At room temperature, there was no significant difference among the values of the resin pieces, whether the pieces had been immersed and shaken in some foods and drinks or not. Increasing the temperature to 150℃, however, there was significant difference among the odor concentration values of the four kinds of denture base resin pieces immersed and shaken in artificial saliva, Coca-Cola, soy sauce and Worcester shire sauce.journal articl
咬筋前縁部より翼突下顎隙に木片が迷入した1症例
Get PDFapplication/pdfThis case report is a rare example of a foreign body, a wood fragment, which persisted in the pterygomandibular space for three weeks. The difficulty in locating the foreign body arose from the fact that radiographs of the jaws did not show a radiopaque object in the buccal and pterygomandibular spaces and trismus showed an opening of only about 0.2cm. Curratage was indicated after trismus, and continuous drainage was slightly improved. A wood fragment lay in close lateral relationship to the mandibular nerve; treatments were conducted successfully without any lingual and lip anesthesia. On the CT scan, wood is usually visualized as a low-density band, caused by air trapped with in the wood. Howerer, over time the CT scan does not image wood as an area of decreased density because the air in the wood is gradually absorded. It was believed that computer tomography should also be provided for a diagnosis of foreign bodies such as wood fragments as soon as possible.journal articl
中国石家荘市における小児歯科検診結果
Get PDFapplication/pdfThe important role of the deciduous tooth in growth and development during the infant period shows a strong tendency to suffer from decay before the completion of a deciduous dentition. The prevention of an increasing tendency toward dental caries in young children is thus an urgent task in pediatric dental medicine, and caries prevention must be performed under public hygienic policy affecting all the public. Thus, accurate epidemiologic grasping of the actual phase of deciduous tooth decay is very important for preparing preventive measures against dental caries in infants. The speaker et al. carried out a dental inspection of kindergarten children in Shihchiachuang-city , China and investigated conditions of those suffering from dental caries and its oral conditions. Their results were subsequenty compared with those of the Welfare Ministry who had investigated children of the same age in Japan and then discussed. The survey was performed in regard to malocclusion, tooth Anomaly, gingivitis, inspection of dental caries and included an examination of caries activity in 600 kindergarten children of Shihchiachuang-city (334ma1e, 266 female). The dental caries inspection was carried out according to the criteria of the Japanese Welfare Ministry and the results were classified according to the four grades of caries progression from C_1 to C_4. We carried out a dental inspection of three-to six-year-old kindergatren children in Shihchiachuang-city, compared its results with those of a Japanese survey and obtained the following conclusions: 1) The frequency of malocclusion was 13.8%; this showed no difference between China and Japan, and also no difference in tooth disorder. 2) The rate of the gingivitis contraction was 10.8% -very low in comparison with 40 to 70% rate in Japan. 3) Regarding the comparison of the caries incidence rate mean number of dmf and the rate of dmft, the rate of those suffering from caries, especially in three-year-old children of Shihchiachuang-city was higher, showing a tendency toward the earlier appearance of dental caries in comparison with Japanese infants.journal articl
Philipp PfaffのAbhandlung von den Zähnen des menschlichen Körpers und deren Krankheiten(1756年刊)について
Get PDFapplication/pdfThe first German to write a treatise on Dentistry was Philipp Pfaff, Dentist to Frederick the Great, King of Prussia. His work was long considered an important text book, but was not widely known except for his records of pulp-capping, a wax impression taking, and the use of plaster models. Recently, I read his book in a reprinted edition. The following is a review. In 184 succinct and well-written pages, he discusses the anatomical and physiological notions relative to teeth, as well as preventive dentistry, dental pathology, oral surgery, dental therapeutics, and dental prosthetics. For the most part, this is identical to the work of French dentist Fauchard, but also contains his many original views.journal articl
ウレタン系形状記憶ポリマーの生体親和性について 第1報 寒天重層法による毒性試験
Get PDFapplication/pdfIn-vitro testing methods using cell culture have become common in the evalution of the biologic effects of dental material. One of these tests is described in this paper. It is an in-vitro test using culture to determine the general cytotoxic effect of the urethane shape memory polymer. The Agar Overlay Test (AOT) was used for the cytotoxicity screening of the urethane shape memory polymer and heat-polymerized denture base polymers. A 24-hour culture of human Hela cells was used in this test. Finings of C.C.P. and Asb were used as controls in comparing interpreting the results. In conclusion about 20% of the cells were disintegrated by the heat-polymerized denture base polymer in the decolorized area. However, the urethane shape memory polymer produced no discoloration in areas surrounding or directry underneath it. There were also no disintegrated cells in these areas. When evaluated, these tests showed that the heat-polymerized denture base polymer has some effect on the culture cells. However the urethane shape memory polymer is valuable for dental materials.journal articl
根管形成のガイドライン
Get PDFapplication/pdfIn order to obtain as good a preparation as possible for root canals, which can never be examined directly, appropriate guidelines for mechanical instrumentation are necessary. We conducted a series of experiments to investigate how large the apical portion of the root canal should be prepared during instrumentation in order to assure adequate debridement without risking destruction of the apical portion of the tooth. Anatomical studies, including those we have conducted, have shown that even root canals having a wide, ribbon-like form generally taper to a narrow constriction just short of the apical foramen. Accordingly, instrumentation close to the foramen can be expected to increase the possibility of producing a circular preparation. But the conventional guideline once commonly given for the final size of the preparation was found to be usually inadequate for providing a circular apical preparation, even when instrumentation was conducted to 0.5 mm from the foramen. A set of guidelines for apical enlargement, suggested by Yasuda, advocates a uniform size of enlargement given the type of tooth and canal configuration involved. The suitability of these guidelines, except in instances of severely curved canals, was confirmed through clinical and experimental evaluations of the adequacy of the recommended sizes for various root canal systems. However, it has been observed in experiments with monkeys that instrumentation too close to the foramen increases the risk of periapical complications. We concluded from our experiments with extracted premolars that when instrumentation is conducted to lmm from the foramen, the degree of enlargement specified by Yasuda's guidelines assures an adequate apical preparation, while reducing the risk of extruding debris or destroying the apex, for most of the canal configurations we examined for this type of tooth.journal articl
二層構造型エピテーゼを用いた1臨床例
Get PDFapplication/pdfA patient, a 74-year old man with complete removal of the right maxilla, nasal bone, zygomatic bone, lateral mass of the ethomoid bone and orbit, due to a malignant tumor, was examined. A prior attempt at plastic and maxillofacial surgery for deltopectral flap was unsuccessful because of a poor skin graft and bad circulation of the blood. A large facial defect caused by the treatment was restored by double layered epithese. The inside structure was made of new soft resilient lining material and the outside structure was made of silicone rubber. The weight of the epithese was light and his physiologic functions, i. e., mastication, pronounciation and swallowing, are good. However, we are still concerned about poor physical properties and color changes for the resilient lining material with long term use.journal articl
