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Volume 15 (1965)
- Issue 3 Pages 105-
- Issue 2 Pages 45-
- Issue 1 Pages 18-
Volume 15, Issue 3
Displaying 1-6 of 6 articles from this issue
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[in Japanese]1965 Volume 15 Issue 3 Pages 105-113
Published: 1965
Released on J-STAGE: March 02, 2010
JOURNAL FREE ACCESSDownload PDF (1544K) -
Tyuya KITAMURA1965 Volume 15 Issue 3 Pages 114-125
Published: 1965
Released on J-STAGE: July 27, 2010
JOURNAL FREE ACCESSThe report about growth and development, calcification and eruption year of teeth had been made and published by many investigators but mutual relation between teeth and paradentium was not understood accurately.
Upper and lower central incisors had been continuously observed for 17.5 months (upper 48 samples, lower 11 samples) by contrast radiography, originally, developed for the purpose.
Clinical teeth crown length before and after dental completion is measured and change from clinical dental crown length to anatomical crown length after dental emergence was observed in 526 samples (upper 279, lower 247) in association with continuous observation groups.
Obtained results were as follows :
1. Rider was set on the cutting-edge of incisor and labial surface of dental crown and gingival boundary line were plastered with contrast medium. Approximately value of clinical dental crown length and teeth length from radiography were found.
2. When the teeth in jaw attained three-quarters of completed teeth length, their eruption was found in oral cavity.
3. Judging from continuous observation groups, growth velocity of clinical dental crown length and teeth length in upper or lower jaws fast, 4 or 5 months after eruption but slower late after its time.
4. Clinical dental crown length attained one-half of anatomical crown length in upper jaw about a year after emergence and in lower jaw about a year and 2.5 months.
5. From the result of statistical analysis, the developmental relation between clinical dental crown length and teeth length was of high correlation.
(r=0.97, Y=-15.92 + 0.94 X, in upper; r =0.98, Y=-11.014-0.76 X, in lower)
6. Judging from continuous observation groups and other observation groups, the root was complet 27.17 months in upper and 30.93 months in lower after emergence.
7. Clinical dental crown length was in upper about 60.9 % and in lower about 58 % of anatomical crown length at the time of root completion.
8. After root completion, clinical dental crown length was linear in semi-logarithmic table. Clinical dental crown length increased in propotion to a logarithm of months.
9. Clinical dental crown length was in accord with anatomical crown length in upper 822 months (approximately 69 years) and in lower 619 months ( approximately 52 years) after emergence.View full abstractDownload PDF (3181K) -
Condition of application and segregation amount of tin by pHTakeshi HIROSE1965 Volume 15 Issue 3 Pages 126-137
Published: 1965
Released on J-STAGE: March 02, 2010
JOURNAL FREE ACCESSStudies were conducted, from the standpoint of tin, by making use of radioactive tin-113, on the anti-corrosive effect of stannous fluoride on the enamel of an extracted tooth.
The radioactive stannous fluoride was produced by leaving a large quantity of 113SnF2 mixed with a very small amount of 113SnCl2 as it was for 3 hours, in order to transform 113SnCl2 obtained into 113SnF2. Therefor was used the substitution equivalent to effect halogen ion of fluorine (F) and chlorine (Cl) adhering to tin ion (Sn++) of both elements.
As the experimental item, the conditions and adhering status of stannous fluoride at the time of application were measured by the well-type scintillation counter from the aspect of radioactivity, while the domain of its segregation was observed by auto-radiography. And, measurement was also made on the segregation amount of tin in the acid-alkali solution.
The results obtained were as follows :
1. It is optimum to apply the ointment at 8% in concentration for 2-3 hours.
2. The tin of stannous fluoride adheres evenly to the surface of healthy and normal enamel, especially much to the carious and damaged parts.
3. The segregation of tin caused by the acid-alkali solution is more violent as acid is stronger, and a large amount of segregation of tin in pH 5.0-pH 3.0 has been observed since the early stage.View full abstractDownload PDF (2597K) -
Shoogoro OKADA, Hiromasa AKADA, Takashi NAGAI1965 Volume 15 Issue 3 Pages 138-144
Published: 1965
Released on J-STAGE: March 02, 2010
JOURNAL FREE ACCESSRecently, the accumulation of radioactive strontium in human bone and teeth caused by nuclear bomb test fallout are increasing. Kerwin proposed the speculation that the retention of radioactive strontium in human body will be increased by drinking fluoridated water everyday, because strontium and fluorine may precipitate within the body as insoluble SrF2. The purpose of this study was to investigate the retention or accumulation of radioactive strontium in the body of animals drinking fluoridated water in graded concentration.
Experimental method and result were as follows:
Four-week aged rats were used for this study. All animals received relatively low fluoride diet and fluoridated drinking water throughout the experiment. According to the concentration of fluorine in drinking water, the animals were divided into 1, 10, 25 and 100 ppm of fluorine groups and control group, and fed for forty days. At forty-first day, those animals were orally administered a single dose of 89Sr, and were sacrificed after one, ten and twentyfive days. 89Sr in femurs in all groups and 89Sr in lower incisor in 10 and 100 ppm fluorine group and control group were analysed.
The significant increase of radioactivity over that of the respective control group were found in 1 ppm fluorine group sacrificed on the 26th day and in 100 ppm fluorine group sacrificed next day, while other experimental groups showed no significant difference compared with the control group.
Following the above experiment, the accumulation of 89Sr in rats was investigated, which were given 89Sr everyday through the experiment. The animals were first given 1, 10 or 50 ppm fluoridated water and low fluoride diet respectively for four weeks and then 89Sr was added to the ration for fifty days. Finally 89Sr in femur and incisor were analysed.
Nither average value of 89Sr in femur nor in incisor in experimental groups (drinking fluoridated water) showed significant differences as compared with that of the control group (drinking distilled water).
The conclusion drawn from above two experiments was that there was no constant correlation between fluorine concentration of drinking water and the retention of 89Sr in hard tissue. And the accumulation of 89Sr in hard tissue in fluoridated groups were not significantly higher than that of the control group even after 50 day administration of 89Sr. Based on these findings the authers could not acknowledge the validity of the speculation of Kerwin.View full abstractDownload PDF (1234K) -
I. Tooth marking by EDTA-Pb for the Experimental Caries Study in Wister RatsMasao ONISI, Fumiko OZAKI, Tasuku MIMURA, Hideaki OGURA, Sachiko TAMAO ...1965 Volume 15 Issue 3 Pages 145-149
Published: 1965
Released on J-STAGE: March 02, 2010
JOURNAL FREE ACCESSA rat marked in its dentin by some bone or tooth marker during the dentinogengtic studium, being exposed to the caries producing diet after weaning would be useful to estimate the depth of the carious lesion and the effect of factors to influence dentinal calcification. The results from experimental caries produced on this Pb-marked rat will bring some more favor for caries research. Working on such rat tooth, on the other hand, rat dentin marked by Pb injection must not exert any effect on general growth of the rat and developement of the carious lesion.
About half of total 143 Wister rats, obtained from two females and 8 males were injected with aqueous solution of Pb-Na2-EDTA at 10th, 12th, 14th days after birth. After weaning, all animals were challenged by the caries-producing diet, 6PMV, for 90 days. Both groups, Pb-marked and control, were compared with respect of average number of produced occlusal cavities or lesions and body weights. Thereafter, tooth was decalcified in the decalcifying solution saturated with H2S and sectioned for the microscopic examination.
The slightest differences of average lesions and body weights in both groups at the end of experiment were found but proved to be insignificant by statistical treatment (Fig. 1). Three black lines marked by Pb injection were usually found in dentin under a microscope (Fig. 2). In few cases, however, part of the lead-lines disappeared discontinuously at the bottom of fissure (Fig. 3-A). The deepest front of bacterial invasion of one dentinal tubule reaches extremely profound but at the nearest tubule, it appears almost inaffected. Therefore, instead of primal assumption, the degree of invation by carious attack could not estimate by these lines. However, this rat could be useful tool for the study of carious lesion and resistance of dentin against cariogenic agents, when they were added during two EDTA-Pb injections.
Much stress was placed on the findings at the lead lines which would not receive any visible affection by bacterial invasion (Fig. 3-B). Final disscussion on this findings will appeared on the succeeding report.View full abstractDownload PDF (1416K) -
II. Location and its scoring system of Wister rat caries produced by high sugar dietMasao ONISI, Fumiko OZAKI, Sachiko TAMAOKI1965 Volume 15 Issue 3 Pages 150-155
Published: 1965
Released on J-STAGE: March 02, 2010
JOURNAL FREE ACCESSOf practical aim to reach the simplest recording and severity of rats caries, 3133 lesions or cavities of carious affection appeared in 374 Wister rats of 7 different experimental caries researches on the high sugar diet, 6 PMV, were treated statistically (Table 1).
Frequency of cavities differed at various locations of molars (Fig. 1), but almost coincide at right and left sides. Thus it is possible that one side of molars was submitted to the macerated preparate for easyer counting and another side was reserved for the histological examination. Negrecting smooth surface caries and cavities at irregular fissures, counting location were simplified into 12 fissures in one side and only 1.94% of cavities was discarded (Table 2). If two more regular fissures with fewer occurrance were neglected in scoring, cavities appeared on remaining 10 locations including 94.92% of total cavities (Table 2). These 12 fissures were location 1, and 2 at the 1st., location 5 and 6 at the 2nd., location 7 and 8 at the 3rd upper molars, and location 8 at 3rd., location 5 and 6 at the 2nd. and location 1, 2 and 3 at the 1st. lower molars, in order of caries frequency. When 10 locations were choised, two more fissures, location upper 7 and lower 8, could be subtracted from the 12 location system (refere with Fig. 1). Proposed models of the scoring table are shown in Fig. 3-A and 3-B. Grading of caries affection of one rat is possible to represent by number of cavities found on major 6 locations. According to the results at Table 3, the most probable pattern of conbineing locations would be as shown in Table 4.View full abstractDownload PDF (904K)
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