The periodontal status of 257 Japanese company employees aged 20-56 yr was studied to determine the number and percentage of subjects with and without bleeding after gentle probing in the sextants ...given a Code 2 using the CPITN. In addition to recording the presence of calculus in the conventional manner, a modification was introduced to add a Code 2+ for sextants in which bleeding after probing was found and a Code 2- where no bleeding was detected. The results indicate that 38-52% of the sextants given a Code 2 showed no bleeding after probing. Such a large percentage of sextants with no evidence of bleeding in the presence of calculus raises a question about the priority which should be accorded to provide scaling for these subjects. The results also show that of the 116 subjects aged 20-29 yr judged to be in need of periodontal treatment by the CPITN criteria 18.1% showed neither pocket formation nor bleeding. Modifications to the CPITN are suggested which should make the index more appropriate for assessing both the prevalence of periodontal disease and the need for periodontal treatment and thus make it more useful for public health planning and evaluation purposes.
The purpose of this study was to examine trends in caries prevalence during 1970-90 in the junior high school students aged 12-15. A total of 840 children from 1st (12-13-yr-olds) to 3rd ...(14-15-yr-olds) school grade in the junior high school in Shizuoka city, Japan, was examined in 1990. The caries prevalence in 1990 was then compared with the data which had been collected from the longitudinal survey by Katayama (1970-72) and the cross-sectional survey (1985) on schoolchildren in the same junior high school. The results indicated that DMFT and DMFS indices in the 1st school grade in 1990 were significantly lower than in 1985 (p<0.05) and in 1970-72 (p<0.01). The DMFT indices at age 12-13 were 5.47 in 1970-72, 3.60 in 1985, and 3.09 in 1990. Percentage decreases in DMFT at age 12-13 were observed in the maxillary incisors (36%), maxillary molars (21%), and lower molars (13%) during 1985-90. The percentage decrease per annum of DMFT index at the age of 12-13 in the examined population was relatively low (-2.9%) in comparison with other industrial countries. Likewise, the downward trends in caries prevalence were apparent in the 2nd and 3rd school grades during 1971-85, but no significant change was observed between 1985 and 1990. The reason for the change during 1985-90 in this population is not clear, but the study shows that the frequency distributions provide valuable information for monitoring changes and high risk groups in caries prevalence.
The purpose of the present study was to investigate the prevalence of root caries in an elderly Japanese population. A total of 265 elderly people over 60 years of age were examined between 1990 and ...1991. Of these subjects, 161 dentate elderly people, who had 12.8 present teeth on the average, were available for assessment. The proportion of sujects with gingival recession in this population was 62.3% in the 60-69-year-old group, 45.9% in the 70-79-year-old group, and 38.2% in the 80+-year-old group, with an average of 49.7%. The percentage of the subjects with one or more cases of active root caries was 13.7%. The prevalence of active root caries ranged from 10.8% at age 70-79 to 17.6% at age 80+. The proportion of persons with active and/or inactive root caries ranged from 18.9% at age 70-79 to 24.5% at age 60-69. The percentage of subjects with active and/or inactive caries and/or root fillings varied from 23.5% at age 80+ to 32.1% at age. 60-69. The prevalence of active root caries in the subjects at risk (with gingival recession) was 27.5% on the average and ranged from 23.5% at age 70-79 to 46.2% at age 80+. The percentage of persons with active and/or inactive root caries and/or root fillings in the subjects at risk ranged from 51.5% at age 60-69 to 61.8% at age 70-79. The mean number of teeth with active root lesions was 0.24 per person and the mean number of teeth with root fillings was 0.37 per person. The percentage of subjects with root abrasion ranged from 10.3% at age 60-69 to 37.0% at age 80+, and the mean number of teeth with root abrasion was 0.72 per person. These results suggest that the prevalence estimate of root caries varies with changes in the diagnostic criteria and definition, and seems to be influenced by filled abrasions and the number of present teeth as complicating factors. In an elderly population, we recommend that factors involving root lesions, such as active and inactive root caries, root fillings, root abrasion, and the number of teeth must be included in an estimate of root caries prevalence.
Fluorine contents and total hardnesses of municipal water supply in 102 principal cities in Japan were determined by SPADNS-zirconium method and EDTA method. 1) Fluorine contents of water ranged ...generally from 0.05 to 0.2 ppm. Cities with common water supply containing over 0.2 ppm of fluorine were; Kumamoto (0.23), Toyonaka (0.27), Tsushima (0.29), Takarazuka (0.32), Kyoto (0.62-experimentally fluoridated-Yamashina area) and Kasaoka (1.2-1.3 ppm). 2) Total hardnesses of water (expressed as CaCO3) ranged generally from 40 to 100 ppm; most of them appeared to belong to soft water. In some cities, total hardnesses were above 250 ppm, e. g. Mobara (256.7) and Kasaoka (280.3ppm). Itoigawa was supplying moderately hard water (184.1 ppm) and there were eleven other cities distributing slight hard water (100-150 ppm).
A survey of prevalence of dental caries and mottled enamel was made on 1, 200 school children (6-12 years of age) at Kasaoka city of Okayama prefecture in western Japan, where the municipal water ...supply had been accidentally fluoridated at 1.2-1.3 ppm or more for nine years. Results were summarized as follows: 1. At the period of survey, the fluoride concentration of the municipal water supply ranged from 0.9 to 1.3 ppm in tap water of several spots In the city; however, it would have ranged from 1.4 to 1.8 or more during the earlier period of the water supply operation, because there were four water source wells which started respectively to operate at different dates. 2. The domestic well water in this district contained also an average of 0.52 (±0.44) ppm of fluoride. 3. The percent of persons with one or more DMF teeth was significantly lower than that of the non-fluoridated group (inhibitory rate: 40%), while the percent of persons with mottled enamel was in average 40% in this group (however, moderate or severe grade cases were only 8.5%). 4. There were no significant difference in the dental caries prevalence between the municipal water group and the domestic water group, while the mottled enamel prevalence was distinctly higher in the former. 5. Several numbers of moderate grade cases of mottled enamel were found even in groups taking fluoride lower than 1.0 ppm and also there were several cases in taking as low as 0.5 ppm. 6. There is likely a correlation between the fluoride concentration of drinking water and urine in the range from 0.5 to 3.2 ppm in water.
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