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Volume 29 (1979 - 198･･･
- Issue 4 Pages 346-
- Issue 3 Pages 276-
- Issue 2 Pages 90-
- Issue 1 Pages 1-
Volume 29, Issue 3
Displaying 1-7 of 7 articles from this issue
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Yasuko KOBAYASHI, Masami OZEKI, Mitsuru TAKEI, Ryoyu SHIMANO1979 Volume 29 Issue 3 Pages 276-290
Published: 1979
Released on J-STAGE: March 02, 2010
JOURNAL FREE ACCESSLanthanum inhibits dental caries formation in hamsters infected with Streptococcus mutans, adherence of human oral microbes to the glass surface, and change the microbial flora in the oral cavity of hamsters.
We used non-carious extracted human teeth with the enamel surface polished. After thes teeth were treated in 8% lanthanum nitrate solution, at regular intervals absorption of La by the enamel surface was quantitatively analyzed with an electron probe X-ray microanalyser, taking as an index the quantity of Ca and P in the enamel surface.
Uptake of La was observed 4 hours after the treatment. The Ca of the enamel surface was reduced and La increased. After 3 day the quantity of La reached a state of equilibrium, fluctuating between 50 and 60%, and the movement of P was small.
We observed that La displaces Ca in the enamel surface and that after long treatment thesurface becomes coated with La.View full abstractDownload PDF (17279K) -
Part 1 Residual Fluoride Amount and RateJun KISHI, Sumiko OIKAWA, Toshio KOTAKE, Fumiyuki TSUZUKI, Toshio NAGA ...1979 Volume 29 Issue 3 Pages 291-298
Published: 1979
Released on J-STAGE: November 26, 2010
JOURNAL FREE ACCESSFor caries prevention, the NaF tablets chewing method was introduced to 1, 233 children (626 boys and 607 girls) at a certain primary school in Ibaragi Prefecture.
In this study, the residual fluoride amount and rate in the mouth after chewing two tablets which contained 0.905 mg of fluoride were determined with an ion meter (Orion, model 407 A) using a fluoride ion activity electrode. (Orion, model 94-09)
The amount and rate of residual fluoride in the mouth was 0.319 mg (35.2%) in boys, 0.295 mg (32.6 %) in girls, and 0.307mg (33.9%) in the whole sample. The maximum retention was 0.819 mg (90.5%) and the minimum was 0.030 mg (3.3%), and the standard deviation was 0.110 mg (12.1%). 789 children (60%) had a retention rate between 20-40%.
These findings indicate that the amount and rate of fluoride in mouth were remarkably different by class, grade and sex. But these results can be considered standard, since the method has been used for more than six years under the direction of school health officials.View full abstractDownload PDF (1425K) -
Okiuji TAKAGI, Yoshihiro SHIMADA1979 Volume 29 Issue 3 Pages 299-305
Published: 1979
Released on J-STAGE: March 02, 2010
JOURNAL FREE ACCESSThe purpose of this investigation was to detemine what influence the early extraction of carious deciduous molars had on the eruption ages of permanent bicuspids.
The investigation was based on dental records which were accumulated by a dental health program in 1972-1974 for 80 boys and 91 girls aged 6 years in the first grade of primaryschool in a rural village where there was no dentist. The program was composed of annual dental inspections followed by the extraction of carious deciduous teeth and the filling of carious permanent teeth. At the dental inspections, a tooth was regarded as erupted if any portion of the crown was visible and was also recorded for 4 to 6 years.
In order to estimate the effect of early extraction of deciduous molars, the eruption ages of their bicuspids were grouped by the condition of deciduous predecessors either extracted at 6 to 8 years of age or not, and the cumulative frequency distribution of the groups and their median ages were compared.
From the findings, it was clear that the eruption ages of maxillary bicuspids were greatly accelerated by the early extraction of deciduous predecessors but the mandibular bicuspids were either not affected or slightly delayed. The median eruption ages of maxillary successors in the groups of deciduous predecessors extracted were approximately 1 year to 2 years earlier than the groups of without extractions, but the median ages of mandibular successors of the extracted groups were the same or slightly late (Table 2, Fig. 1 to Fig. 8).
Futhermore, the correlation coefficients between the extraction ages of deciduous molars and the eruption ages of permanent successors were calculated for each tgpe of permanent bicuspids and for different sex, but no statistically significant correlations were found (Table 4).
The results of this investigation indicated that the early extraction of carious deciduousmolars at the age of 6 to 8 accelerated the progress of the maxillary successors but not that of the mandibular successors.View full abstractDownload PDF (1177K) -
EnamelDestruction caused by Lactic, Propionic, and Citric AcidShigeru YOSHIDA, Toshibumi ISHII1979 Volume 29 Issue 3 Pages 306-317
Published: 1979
Released on J-STAGE: July 27, 2010
JOURNAL FREE ACCESSThe object of the present experiment was to observe continuously the pattern of structural changes in the surface layer of enamel produced by the action of lactic, propionic, and citric acid, and also to compare these changes with those previously reported for acetic acid and ethylene diamine tetra-acetic acid (EDTA). According to the sandwich method devised by us, a plano-parallel thin section of tooth was cemented between the cover and slide glass using an adhesive material, with exposure of the outer area of the enamel surface alone. The decalcifying solution was then permited to act on the surface area in order to observe continuously the main changes under the microscope. Exposure times varied from approximately20 to 100 hours. After the decalcification, contact microradiographs of each decalcified section were prepared.
The main findings are as follows. The ends of the striae of Retzius and some small defects including narrow channel-like defects appeared to be the point of the initiation of attack, as already reported in the study on acetic acid and EDTA decalcification. This phenomenon seems to be independent of the organic acid used. The spread and degree of enamel destruction owing to the action of citric acid were more rapid and pronounced than in acetic, lactic, and propionic acid decalcification. Citric acid attack on enamel was characterized by preferential dissolution of the peripheral regions of prisms and the striae of Retzius, whereas the etching pattern of other organic acids seems to be unrelated to prism morphology.View full abstractDownload PDF (9995K) -
Yoshihiro SHIMADA, Katsuhiko TAURA, Katsuyoshi SHIROTO1979 Volume 29 Issue 3 Pages 318-327
Published: 1979
Released on J-STAGE: March 02, 2010
JOURNAL FREE ACCESSTo find a representative method of partial mouth recording for Russell's Periodontal Index, the eleven methods of partial recording were compared using the data from 362 male subjects aged 15 to 21 years.
The eleven methods were three kinds of half-mouth methods, six kinds of selected six-tooth methods and two kinds of anterior segment examination methods. The half-mouth methods were right side unilateral recording, left side unilateral recording, and alternating bilateral recording recommended by the WHO for dental caries survey. The six teeth of the selected six-tooth methods were and . The anterior segment methods were recording of both upper and lower segments and recording of the upper segment only.
In the statistical analysis of the difference between the values of the original whole-mouth method and the partial-mouth methods, all of the half-mouth methods and the Ramfjord's six-tooth method gave values which were not significantly different from the original method, but the values of other methods were different (Table 5).
In the study of the correlation between whole-mouth and partial-mouth methods, the correlation coefficient of alternating bilateral method was highest and was lowered in following order: left side method, right side method, modified Ramfjord's six-tooth method permitting the substitution of a missed first molar by a next second molar, Ramfjord's six-tooth method, other six-tooth methods, and anterior segment methods (Table 6). From the statistical comparison of the correlation coefficients, the estimates for all half-mouth methods were significantly higher than other partial recording methods and the estimates for anterior segment methods were also significantly lower than all other methods (Table 7).
It was concluded that the alternating bilateral half-mouth method was the best partial recording for the Russell's Periodontal Index in spite of its requiring the longest time, and that the Ramfjord's six-tooth method and the modified method permitting the substitution of a missed first molar by a next second molar were relatively good because there was no great difference from the value of the original method and much time was saved.View full abstractDownload PDF (1648K) -
Mitsumasa TAZAWA, Yoichi IIJIMA, Toshihide KUMETA, Masato MIYAZAWA, YE ...1979 Volume 29 Issue 3 Pages 328-339
Published: 1979
Released on J-STAGE: July 27, 2010
JOURNAL FREE ACCESSThis study aimed at evaluating the effect of caries reduction with natural fluoride in the drinking water for the different types of permanent teeth. The study was conducted to survey of 370 schoolchildren in a fluoride area (Kitatsugaru, Aomori; F 0.3-3.2ppm) and of 528 children in a non-fluoride area (Matsuo. Iwate: F<0.1 ppm), aged 6-11 years. Both communities belong to a rural area of northern Japan. Social, economical, and environmental conditions are almost identical in these two communities. Furthermore, caries prevalence in the non-fluoride area is very close to the data obtained from the National Caries Survey (1975) of Japan for the age group studied in this report.
Caries reduction of the upper incisor group (1, 2) was remarkably higher in the fluoride area, especially in the children of age 11. With regards to the percentage of the children with DMF in the upper incisor group, the fluoride area percentage was 4.6% vs 37.9% in the nonfluoride area. As a consequence, the caries reduction rate was 88%. On the other hand, the percentage of the children with DMF in the lower 1 st molar group (6) was 66.6% (caries reduction rate: 16.6%) in the 0.8ppm fluoride drinking water group and 64.9% (caries reduction rate: 18.8%) in the 0.90-1.06ppm fluoride drinking water group, and that of the non-fluoride area was 79.9%.
With DMFT indices (Mean DMF) of whole erupted teeth examined in 0.8ppm and 0.90-1.06ppm fluoride drinking water groups, the value of the fluoride area was approximately 1/2 of the non-fluoride area through the ages of 6-11. At age 11, the DMFT index was 4.3 in the non-fluoride area, and 2.3 in the 0.8 ppm and 1.9 in the 0.90-1.06ppm fluoride area.
No significant differences were observed between fluoride and non-fluoride areas concerning teeth eruption rates in different age groups or different types of permanent teeth. Delayed or accelerated eruption of teeth during the ages of 6-10 in a fluoride area, compared with a nonfluoride area has been reported, but delay of tooth eruption caused by fluoride was not found in our study.View full abstractDownload PDF (2266K) -
1979 Volume 29 Issue 3 Pages 344
Published: 1979
Released on J-STAGE: March 02, 2010
JOURNAL FREE ACCESSDownload PDF (197K)
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