Since 1995, we have carried out an Oral Health Program in Toyama prefecture. The budget for this Program is subsidized by the prefecture, and financially assists community oral health projects in the municipalities (cities, towns and villages) in Toyama prefecture. This Program was subdivided into Basic and Optional Programs and this study evaluated the effects of Basic Oral Health Program. The results are as follows: 1. In the 12 municipalities where Basic Program was carried out from 1996 to 1999, the caries prevalence in 3-year-old children was lower than that in the 14 municipalities where Basic Program was not carried out. This result suggests that the Basic Program effectively reduced dental caries. 2. None of the municipalities had dental health officers. However, the percentage of municipalities carrying out community oral health projects has increased due to the subsidy from the Basic Program. This finding indicates that the Basic Program promoted community oral health projects in the municipalities. 3. The municipalities provided with the Basic Program had a lower population of 1.5-year-old children than the municipalities with no Basic Program. It was suggested that the municipalities with a large population had difficulties in carrying out community oral health projects.
This study investigated unpleasant components of physiological malodor to clarify their origins from a microbiological perspective. 1. Expired air from healthy adults with physiological malodor was found to contain more than 15 volatile components, including low-molecular weight fatty acids, nitrogen compounds, and sulfur compounds (VSC). The concentration of methyl mercaptan (CH3SH) in the expired air of subjects with physiological malodor was always above the CH3SH recognition threshold, and was highly correlated with the degree of maloder present. 2. The origin of CH3SH in physiological malodor was examined. The proportion of CH3SH in VSC was higher in mouth air and in the salivary headspace than in expired air. The production of CH3SH in the oral cavity was found to increase following mouth rinsing with a L-methionine solution. The most effective method of reducing the CH3SH concentration in the physiological malodor was to remove the tongue coating. 3. The CH3SH production capacity of 71 oral strains of various genera and species was tested. The genera Porphyromonas, Fusobacterium, Spirochetes, which are presumed to originate with periodontal disease, demonstrated high CH3SH production capacity. In addition, Veillonella, a genus consisting of major microorganisms found in the tongue coating, demonstrated similar abilities. From these results, it was cleared that CH3SH is one of the primary components of physiological malodor and produced mainly from tongue coating which harbors sizable Veillonella populations.
This study surveyed the opinions and attitudes of dental hygienists in Japan on methods of caries prevention including the use of fluorides. The subjects were working in public offices and health centers and performed dental health services. A questionnaire was designed according to the PRECEDE model, which was comprised of predisposing factors, enabling factors, reinforcing factors and diagnosis of behavior. The results were as follows: 1. Dental hygienists in Japan who worked in public offices and health centers showed accurate knowledge about the use of fluorides and positive attitudes toward dental caries prevention. Despite the high proportion of the subjects presenting a favorable opinion on the topical application of fluoride, less than 40% of hygienists agreed with systemic fluoride application. 2. More than 50% of the population indicated their strong dissatisfaction with enabling factors consisting of a dental health budget, sufficiency of personnel and so on. Hygienists showed a negative response to reinforcing factors as well, which were mostly comprised of perception and support from colleagues. 3. In diagnosing behavior, which was represented as a choice for procedure of caries prevention, plaque and sugar control was almost at the top of the procedures. A very small proportion of the subjects supported systemic fluoride application such as water fluoridation.
We conducted oral health care and dental examination for 49 fragile elderly at lending at the day service center of Oketo Town in May and December in 1999, and we instructed the staff in methods of tooth brushing. Among these users, 36 subjects underwent both the first and second dental examinations. As a result of comparison between the first and second examinations, the stability of the maxillomandibular denture was significantly improved among the subjects (p<0.05), a proportion of the subjects demonstrating denture repositioning while sleeping significantly increased (p<0.05), and the percentage of subjects using the detergent for denture significantly rose at the second examination (p<0.01). Although the difference was not significant, the average number of decayed teeth per individual decreased slightly, the condition of oral mucosa was improved, and the subjects became able to perform oral hygiene and denture cleaning slightly more frequently. Moreover, the subjects reported that they felt better, and their family reported that the subjects began to talk more frequently after receiving oral health care. These results suggest that oral health care activities increase the Quality of life in fragile elderly persons.
The present research investigated mechanism of protection against cadmium (Cd) sensitivity and Cd toxicity in human oral tissue using cells isolated from human gingiva and periodontal membrane. The results obtained are as follows. 1. Cell growth and DNA synthesis were inhibited in fibroblasts isolated from adult gingiva and periodontal membrane as well as infant gingiva at Cd concentrations of 10-5 mM and above. There were no obvious differences in Cd sensitivity according to cell type. 2. The intracellular concentration of Cd in cells exposed to Cd for 24 hours was lower (10-7〜10-5 mM Cd) than that in control group for all cell types and was highest in the 10-3 and 10-1 mM Cd concentration groups. 3. The intracellular concentration of GSH in cells exposed to Cd for 24 hours was high in the group with a high intracellular concentration of Cd. 4. Induced synthesis of MT by Cd was observed for 12 hours of exposure in all groups up to a Cd concentration of 10-3 mM, and was even greater at 24 hours. In contrast, MT induction was not observed in any cell type at a concentration of 10-1 mM. 5. Tissue staining with fluorescent antibody revealed that MT was located mainly in the nucleus in all three types of cells. 6. MT-II mRNA expression was observed in human periodontal membrane-derived fibroblast cells exposed to Cd for 6 hours. Based on the above findings, it is concluded that there were no clear differences in the sensitivities to Cd of adult gingival cells, adult periodontal membrane-derived fibroblasts and infant gingival fibroblasts. The results also suggest that the production of both MT and GSH are promoted by Cd exposures in all types of cells studied. Finally, MT-II mRN A was detected in adult periodontal membrane-derived fibroblasts exposed to Cd, indicating that MT- II, as an isotype of MT induced in these cells, is present.
According to the Japanese National Oral Health Survey in 1999, the prevalence of gingivitis among 5-14-year-old children is 47.4%. The use of dental floss is important in preventing gingivitis. The present study investigated the effect of a gingivitis prevention program with the use of dental floss. Thirty-nine 5th graders at "M" elementary school (test group) and eighteen 5th graders at "Y" elementary school (control group) were included in this study. Subjects in the test group were instructed by dental hygienists to use dental floss for anterior teeth in combination with regular toothbrushing after lunch. Measurements were carried out by the same dentist at the baseline and at 6 months, using the modified papilla bleeding index and the plaque index for the anterior 10 papillae. At the baseline, there were no differences between the percentages of proximal bleeding sites per person, of plaque per person, or the percentage of subjects using dental floss in their own home. During a 6-month period, the number of bleeding sites per person decreased from 4.67 (SD=3.01) to 3.03 (SD=2.70) in the test group, and increased from 4.59 (SD=2.50) to 5.41 (SD=3.43) in the control group. There was a significant difference in the reduction of bleeding sites in both groups (p=0.003, Mann-Whitney U test). The number of plaque sites per person decreased from 4.64 (SD=3.02) to 3.41 (SD=2.68) in the test group, and increased from 5.12 (SD=2.93) to 6.41 (SD=2.62) in the control group. There was a significant difference in the reduction of plaque sites in both groups (p=0.003, Mann-Whitney U test). The percentages of subjects using dental floss in their home after instruction during the baseline period was 51.5% for the test group and 22.2% for the control groups (p=0.023, chi-square test). These results show that a gingivitis prevention program including the use of dental floss contributes to the prevention of gingivitis in school children. It is suggested that the program in the present study is relatively easy to include in a school-based dental program and can be widely used.
Tooth grinding, an indispensable part of dental treatment, produces a dust that contains bacteria and viruses. This dust can cause environmental pollution in the dental clinic and the dental staff are exposed to scattered dust. Therefore, it is important to remove the dust as it is created at the preparation point. In this study, we evaluated preparation of extracted upper central teeth by four dentists using a manikin, and tried to investigate the exposure of the dentist to tooth grinding dust. We examined the effect of an extra-oral vacuum aspirator and differences in three experimental positions to decrease grinding dust exposure for the dentist in the dental clinic. SPSS was used for statistical analysis. It was suggested that the extra-oral vacuum aspirator effectively achieved about 80% reduction of dust particles measuring more than 0.3 μm. It was confirmed that the most effective position of extra-oral vaccum aspirator in the three experimental position was vertical/upward 5 cm from the preparation point. Therefore, this position should be used when treating patients.
Occlusal balance assessments were performed on individuals with natural teeth in position and fixed molar bridge wearers. Our findings are summarized as follows: 1. Subjects with natural dentition 1) Eccentricity from the displacement of the centroid of the volume of coronal portions measured by the permeable laser method averaged 8.1%. In stark contrast to this, this value was calculated at well over 20% using the Dental Prescale W type. This suggests that displacement of the centroid of occlusal force has a tendency to increase when measured by the pressure measurements paper method. 2) The position of the centroid was found to shift anteriorly when the laser method was used compared with that found by the Dental Prescale. This suggests that the use of the laser will facilitate assessment of occlusal balance including the anterior-posterior occlusal balance. 2. Bridge wearers 1) Before the subjects inserted the bridges, the displacement measured by the laser method was 44.3% on average. The rate dropped significantly to 8.1% (p<0.01) after inserting the bridges. This indicates a remarkable recovery of occlusal balance due to the prosthetic device. 2) In those bridge wearers who have difficulty chewing food, those showing displacement had no difficulty. This finding suggests that whether the occlusal balance in an individual is favorable or not is related to the presence or absence of some food that the person finds hard to chew. From the perspective of maintaining of homeostasis in the oral environment including dentition, it would be meaningful to assess occlusal balance. Furthermore, our study showed that masticatory function can be assessed from the perspective of occlusal balance measured three-dimensionally by the laser method.