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Volume 24 (1974)
- Issue 4 Pages 267-
- Issue 3 Pages 183-
- Issue 2 Pages 57-
- Issue 1 Pages 1-
Volume 24, Issue 1
Displaying 1-5 of 5 articles from this issue
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Masao ONISI, Tyuya KITAMURA, Akemi TOKUMASU, Yoshiko MURAKAMI, Setsuko ...1974 Volume 24 Issue 1 Pages 1-5
Published: 1974
Released on J-STAGE: March 02, 2010
JOURNAL FREE ACCESSA new fluoride dentifrice was used on 335 school children for one year and its clinical effect on caries prevention was estimated by means of comparison with the results obtained from a placebo group of 315 children of a neighboring village of similar socioeconomic status and with so close a caries susceptibility at the initial base line examination that the caries extent or prevalence was 1.90 DMFT or 69.9% at the test village, Okura, and 1.98 DMFT or 69.5% at the control village, Sakegawa. NaF and synthetic zeolite were included 0.2% and 45.0% in the test dentifrice but not in the placebo. The fluoride ion activity of test dentifrice decreased somewhat immediately after preparation, but 78% of the initial activity still remained even when it was kept for 60 days at 40°C. The Children brushed their teeth twice a day for one year. The children in the test village showed 38.0% reduction in caries increment on the smooth surfaces and 11.9% reduction in the pits and fissures. These reductions were statistically proved to be significant at the 0.1% and 5% level respectively.View full abstractDownload PDF (892K) -
Masakazu INOUE, Tatsuko EGAMI, Tadamichi TAKEHARA, Toshiyuki OSUGI, To ...1974 Volume 24 Issue 1 Pages 6-18
Published: 1974
Released on J-STAGE: March 02, 2010
JOURNAL FREE ACCESSBiosynthesis of extracellular polysaccharides from sucrose by oral streptococci is closely related to the formation of dental plaque resulting in the initiation and development of dental caries and periodontal diseases. As a clue to search for useful measures of plaque control based on the clarified relationship between sucrose metabolism by the streptococci and induction of the oral diseases, extracellular sucrases from Streptococcus mutans strain AHT were isolated and purified, and some of their properties were also characterized.
Glucosyltransferase and invertase, but no fructosyltransferase, were constitutively produced in the culture fluid by this strain. Isolation and purification of these two enzymes were carried out in two steps by fractionation with ammonium sulphate followed by isoelectric focusing by electrophoresis and fractionation. The multiplicity or heterogeneity of both of the enzymes was revealed through the fractionation pattern. A glucosyltransferase and an invertase were successfully isolated from each other and the former was purified at 495-fold with 5.3 per cent yield, the latter at 210-fold with 11.5 per cent yield.
The purified glucosyltransferase possessed an optimal pH of 5.0, an optimal temperature ranging from 37 to 40°C, an isoelectric point at pH 6.035 and a Michaelis constant of 3.79 mM sucrose, and was relatively heat-labile. The reaction product of the enzyme was a waterinsoluble glucan. The isolated invertase, on the other hand, had an optimal pH of 6.0, an optimal temperature of 45°C, an Ip of 5.075 and a Km of 0.09 mM sucrose, and was heatstable. The results obtained regarding the properties of the enzymes suggest that invertase may compete with glucosyltransferase for the limited amount of sucrose in dental plaque and may reduced the synthesis of tenacious insoluble polysaccharide, leading to the inhibition of plaque formation in vivo.
The method described by Suginaka et al for the differential determination of sucrase activities was improved so that it was more accurately quantitative. The method was fairly valuable when applied to an enzyme preparation containing various types of sucrase.View full abstractDownload PDF (2959K) -
Shigeru Yamada, Mikiya Hirota, Yutaka Nagata, Fugaku Umezawa, Reiko Ya ...1974 Volume 24 Issue 1 Pages 19-23
Published: 1974
Released on J-STAGE: July 27, 2010
JOURNAL FREE ACCESSThe authors obtained, in previous experimentation, a remarkable inhibition of dental plaque formation by using Chlorhexidine. Using these data, it was easy to express the existence and approximate degree of the effect on dental plaque formation.
In the present experimentation, Chilorhexidine was applied to two types of experimental groups: coating groups and rinsing groups. In the case of the coating groups, if Chlorhexidine was applied for five days successively, the degree of inhibition was 96% after 24 hours. Five days after the discontinuance of its application, the degree was 92%.
In the case of the rinsing groups, on the other hand, the degree was 71% after 24 hours. Five days after the discontinuance of its application, the degree was 89%.
If Chlorhexidine was applied only one day, the degree for both groups was 50% after 25 days. The degree of dental plaque inhibition mentioned above was obtained by the use of the following formula.
A-B/A×100
Where
A; Control group, the average dental plaque index per person.
B; Experimental group, the average dental plaque index per person.View full abstractDownload PDF (783K) -
Heiji Maizumi, Keigo Miyazawa, Yoshio Kobayashi, Masaaki Nanba, Teruko ...1974 Volume 24 Issue 1 Pages 24-29
Published: 1974
Released on J-STAGE: March 02, 2010
JOURNAL FREE ACCESSPig toothbrush bristles imported from China were studied with a scanning electron microscope (model JSM U III manufactured by Japan Electron Optics Laboratory Co., Ltd.) The bristles were coated with carbon and gold, and observed under an accelerating voltage of 10 Kv. The surface of the bristles was not glassy. Under weak magnification the surface looked like bark or elephant skin, but under strong magnification the surface was seen to be scaly. Some abnormal shapes such as crevices or projections were also observed on the surface of the bristles. The form of the tips was varied, and bristles having an ideal tip were rare. This phenomenon is also seen in nylon bristles.View full abstractDownload PDF (2254K) -
1974 Volume 24 Issue 1 Pages 55
Published: 1974
Released on J-STAGE: March 02, 2010
JOURNAL FREE ACCESSDownload PDF (76K)
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