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Volume 20 (1953)
- Issue 4 Pages 229-
- Issue 3 Pages 187-
- Issue 2 Pages 129-
- Issue 1 Pages 1-
Volume 20, Issue 4
Displaying 1-7 of 7 articles from this issue
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Takao Fusayama, Katsumi Yoshizawa, Kazuo Kurosu1953 Volume 20 Issue 4 Pages 229-253
Published: 1953
Released on J-STAGE: October 08, 2010
JOURNAL FREE ACCESSIn making well fitting inlays and crowns, it is necessary to know the dimensional and formal changes of the dies compared with the original preparation, and find methods to reduce such errors. By measuring only the free changes of impression and die materials individually, as hitherto done, the real accuracy of the dies cannot be known. In our studies, the distances between outside walls or inside of the specimen dies were measured. For this measurement the author first originated a set of specially constructed gauges. Measurement of dimensional changes of small specimens of the same size as the practical dies in clinic, with the precision to 0.01%, became possible for the first time by using these gauges together with comparator microscope.
The author originated another set of gauges for use in complementary experiments, by which the distances of the inside walls of specimen dies could be measured comparatively with that of the outside walls under similar conditions. The real dimensional changes are computed by averaging both figures.
Important informations were obtained by using these two kinds of gauges, which will serve the rational use of indirect technique and the improvement of dental materials.
In these studies, alginate and compound were used as impression materials. Hydrocals (Plastone and Duroc), Phosphosilicate cement, Zinc-phosphate cement, Cu-amalgam and Ag-Sn amalgam were used as die materials. The dimensional changes of various dies made of these materials were compared with the original models. Various clinical conditions were introduced into these tests to determine their effects on dimensional and formal changes. The influences of time and separating mediums upon the completed dies were also studied experimentally.View full abstractDownload PDF (10510K) -
Haruko Saito1953 Volume 20 Issue 4 Pages 253-258
Published: 1953
Released on J-STAGE: October 08, 2010
JOURNAL FREE ACCESSCorrosion of thin wires of 18-8 Steel (17.79% Cr, 10.22% Ni, 0.14% C) was observed. Wires, used in this investigation, were 0.15mm and 0.20mm in diameter, three cases of as received, heated at 800°C for 5 minutes (vacuum in 10-2 mmHg) and heated at 970°C for 15 minutes (vacuum in 10-2mHmg) . Tensile strength of wires 0.2 mm in diameter are as follows.
as received 112.0 Kg/mm2
heated at 800°C 91.7 Kg/mm2
heated at 970°C 78.3 Kg/mm2
The corroding reagent was 1% and 3% hydrochloric acid, its temperature was held constant 37°C ± 0.5°C in thermostat with an automatic regulator. The degree of corrosion was examined the definite intervals, one by one.
The degree of corrosion measured by the relation between weigthloss and time of immersion and total tensile strength and time of immersion.
The difference between the thin and thick wire of progress of corrosion existed.View full abstractDownload PDF (2184K) -
Kenzo Kubota1953 Volume 20 Issue 4 Pages 259-263
Published: 1953
Released on J-STAGE: October 08, 2010
JOURNAL FREE ACCESSAs one of the most important volatile component of molten magma, fluorine has been repeatedly reported to be present in volcanic exhalations and mineral springs. Hence it seems important, from the geochemical and medical point of view, to study the fluorine contents in the natural waters of mineral spring areas. The author has conducted an extensive survey of the fluorine contents in 83 natural waters of 21 mineral spring areas on Hokkaido.
The mineral waters of Hokkaido contain a higher concentration of fluorine as compared to most fresh waters which normally have 0.1-0.2 p.p.m. content of fluorine. There seems to be no immediate danger to the population using well waters being affected by so called “mottled enamel”. However among those using mineral waters the majority were affected by “mottled enamel”. Yet such enviroment were scarce. In addition and as a result of the authors clinical observations it is highly probable that tooth decay is reduced by a lower concentration of fluorine than hitherto recognized.
The author has used his own medification of J. M. Sanchis's determination method. He recommends his method since the lowest limit of estimation and sharpness in color changes are remarkably clear and in addition preparation of reagents and analytical procedure are simple.View full abstractDownload PDF (690K) -
Shinkyo Iwao1953 Volume 20 Issue 4 Pages 264-270
Published: 1953
Released on J-STAGE: October 08, 2010
JOURNAL FREE ACCESSDownload PDF (1094K) -
M. Sumita, T. Oshima1953 Volume 20 Issue 4 Pages 271-273
Published: 1953
Released on J-STAGE: October 08, 2010
JOURNAL FREE ACCESSA 55 years old edentulous woman who visited us with a complaint of feeling of fatigue in the angular region of mandibule after wearing of complete dentures which showed minus 0.5 mm free way space, was treated successfully by reducing the bite height.
We constructed two complete dentures newly, the one had 2.0 mm, the other 4.5 mm free way space. In these three, the middle one was seemed to be comfortable and useful for the patient.
Then we came to a decision that the free way space should be taken into consideration in determining the bite height of the complete dentures.View full abstractDownload PDF (2459K) -
Toru Oka, Seiichi Tomizuka, Akira Kodama1953 Volume 20 Issue 4 Pages 273-277
Published: 1953
Released on J-STAGE: October 08, 2010
JOURNAL FREE ACCESSA 54-year-old male farmer, suffering from gas-gangrene over the facial-cervical region caused by pericoronititis of the lower third molar is presented.
He had bilaterally edematous swelling on the cheek, extending to submandibular, submental and cervical regions. Horner's symptom was seen on the right eye.
Swallowing and breathing were remarkably disturbed, but all the trouble disappeared by both surgical operation and administration of chemotherapcutica.
Especially a direct application of antibiotic into the wound can be considered very effective.View full abstractDownload PDF (2529K) -
Masaru Yoshiya, Takeo Mukai1953 Volume 20 Issue 4 Pages 277-279
Published: 1953
Released on J-STAGE: October 08, 2010
JOURNAL FREE ACCESSA new type of constitutional abnormity“Anenzymia Catalasea”was described by S. Takahara and M. Yoshiya for the first time. In most of this abnormity it can be noticed that patients suffer from peculiar gangrenous inflammation, either mild or severe, over the oral mucosa, caused by bacterial infection, in the beginning of the disease, which has a resemblance to alveolar pyorrhoea, but much more malignant symptoms. A 55-year-old male farmaer showing a slight symptom of this disease is presented in this report.View full abstractDownload PDF (1836K)
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