To study how school dental health activities in junior high schools should evolve, we carried out a fact-finding survey in 237 junior high schools in Niigata Prefecture. For this purpose, we followed up the incidence of dental caries in students who enrolled in 1996 and 1997 until they went through the annual spring dental health examination for third graders. In addition, we retrospectively looked into the dental caries rate of these students when they were elementary schoolchildren. Taking into account the regular use of fluoride mouthrinsing at school, statistical analyses were performed after the junior high schools were divided into two groups by the average number of DFT during the two-year period (DFT incidence). 1. Fluoride mouthrinsing in elementary and junior high schools affected the DFT incidence in junior high schools, and a significant difference was observed in the DFT incidence between those schools which implemented the use of fluoride mouthrinsing and those which did not. 2. More than 80% of the junior high schools surveyed implemented eight of 25 items in the school dental health activities, but there were 11 items which were put into practice by less than 50% of the schools. The implementation rate of dental health activities differed depending on whether fluoride mouthrinsing was carried out or not in elementary schools or junior high schools or both schools. 3. When the relationship between the DFT incidence and the implementation rate of the school dental health activities was examined, it was found that the rate of implementation of health guidance, periodontal disease prevention measures and special dental exams were higher in the schools with low DFT incidences than those with high DFT incidences. Among the factors contributing to a decrease in the DFT incidence were the use of fluoride mouthrinsing, a lower number of DFT when subjects were in the first grade of elementary schools, and the implementation of the above-mentioned items in the school dental health activities. From these findings, we concluded that in order to arrest the development of dental caries, it is important to put children under continuous dental health supervision from their infancy and give junior high school students scientific dental health education in addition to encouragement in the use of fluoride mouthrinsing.

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The stimulative effects on blood flow after interdental papillary massage by a toothpick [Dentalpick ® (Koeisha, Osaka) : Toothpick K] compared with an interdental brush were evaluated by a laser Doppler flowmeter using 22 subjects. The values of blood flow before and after massage with toothpick K were 16.0 ± 6.5 and 19.5 ± 5.7 (ALF value), while those before and after massage with an interdental brush were 15.2 + 5.9 and 18.1 ± 4.7 (ALF value). There were significant differences between before and after massage with both supplementary cleaning instruments (p<0.05). Furthermore, the correlation coefficient (r) of the value of blood flow between before and after massage for individual subjects with a toothpick K was 0.83 (p<0.05). These results suggest that toothpick K has the same capability as that of an interdental brush and every subject after massage had a raised value parallel with the value before massage.

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Mouthrinsing is a common oral hygiene practice prescribed for oral malodor. However, commercially available domestic mouthrinsing solutions are not effective against volatile sulfur compounds (VSC) in the oral cavity, which are the main cause of oral malodor. Therefore, we examined the effect of zinc chloride which has been reported as an effective metal salt for oral malodor. Cross-over studies and double blind experiments were designed. Mouth air VSC analyses of eight adult male subjects, diagnosed with oral malodor by gas chromatography, were carried out before mouthrinsing (baseline) with 0.1% zinc chloride or a placebo. Thereafter, the mouth air VSC analyses were repeated following mouthrinsing at 0, 30, 60, and 90 min using a gas chromatograph. Mouth air VSC was dramatically reduced after mouthrinsing with 0.1% zinc chloride solution, and the effect was maintained for at least 90 min. There were no complaints of unpleasant symptoms. However, mouth air VSC was not reduced significantly after mouthrinsing with placebo. The results of this study demonstrate that 0.1% zinc chloride mouthwash is effective for oral malodor. Accordingly, it is reasonable to expect that a mouthwash such as 0.1% zinc chloride will be available in the domestic market.

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In order to establish a preventive program against dental caries for school children, we have performed school dental health activities based on caries risk tests over four years since 1997 in the Izena Elementary and Junior High Schools located on Izena Island in Okinawa Prefecture. Testing of caries risk in all the students (approx. 250 subjects) was carried out annually. Based on the "caries-risk score" calculated from the test assessment, each student was instructed concerning dental health and was motivated to take care of his/her own teeth. Several years after starting the activities, we found some significant outcomes, including a decrease in DMFT in every grade, an increase in the rate of caries-free students, and a decrease in the caries-risk score. This suggested that the dental health activities based on caries risk tests were effective for caries prevention.

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A cohort study was carried out with regard to the development of some systemic functions of 47 pre-kindergarten children aged from 0 to 2 years. Primitive oral reflexes, maintaining a proper posture, oral muscle movement function, proper eating style, systemic function, speech function, and eruption of teeth were surveyed and evaluated as percentile numbers. The following results were obtained : The children whose rooting, sucking, and biting reflexes disappeared earlier than those at the 50 percentile for each of parameters kept their necks steady, sat straighter, crawled, drank with a closed mouth, holding with lips, performed complicated lip movements, cheilion systemic movement, performed opening and closing jaw movements, bit their tongue, and palate, and alveolar tissue, developed hand to mouth eating, and spoke earlier than the group with later disappearance of these reflexes (p<0.05). However, there was no relationship between the primitive reflexes and the systemic functions of running, jumping, and keeping one leg still for more than 2 seconds. Furthermore, the children who could keep their neck steady, sit straighter, stand, and walk earlier than those at the 50 percentile for each of these parameters, drank with a closed mouth, holding with their lips, performed complicated lip movements, showed cheilion systemic movement, performed opening and closing jaw movements, bit their tongue, palate, and alveolar tissue, and displayed hand to mouth eating earlier than the group with later development of maintaining a proper posture (p<0.05). We concluded that with regard to proper eating style, speech function, and systemic function, it is important for infants to be trained in practice as with usual childcare conforming to their development level.

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The purpose of this study was to examine the chief dental complaints and demands for different types of dental treatment among the home-bound aged requiring care, and to identify the factors that cause eating disorders. A survey was conducted of 1,055 aged persons living in urban areas in Japan who had requested home-visit dental treatment. The subjects were interviewed in the format of a questionnaire to obtain information on their dental complaints, demands for different types of dental treatment, oral health condition, chewing problems with their dentures, and general health condition. We also recorded the time of contraction of their causative diseases, the time when they began to receive care, and the time of contraction of their dental disease forming the chief complaints. The results were as follows : 1. By needing care new demands for dental treatment, such as dentures, had been generated. 2. The proportions of demands for different types of home-visit dental treatment among aged persons requiring care were ; 73.5% for denture treatment, 28.8% for periodontal treatment, and 23.6% for caries treatment. 3. 37.0% of the chief dental complaints occurred within 12 months after the aged persons began to require care, 16.8% within 24 months, and 11.3% within 36 months. 4. From comparison of the intervals between beginning to need care and the occurrence of the chief dental complaints, according to the types of dental treatment, the interval to denture treatment was shorter than that to caries treatment and periodontal treatment. 5. The shortest interval according to the age brackets was in the more elderly group (75-84 years old). 6. The chewing condition with dentures before requiring care had no relation to the time of occurrence of eating disorders after requiring care.

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The purpose of this study was to evaluate the effect of a new toothbrush with ion-coated nylon filaments (Ion-coated toothbrush) compared to a toothbrush with conventional nylon filaments (Nylon toothbrush). This was a 2-part study. In part 1, the cell proliferative activity of the junctional epithelium and adjacent connective tissue was evaluated in dog gingiva. A total of six dogs, four teeth of each dog (two for the Ion toothbrush and the others for the Nylon toothbrush), were used. During the 3 weeks of the experimental period each tooth received the daily toothbrushing. The proliferative ability of the basal cells of the junctional epithelium and fibroblasts of the adjacent connective tissue were evaluated for expression of the proliferating cell nuclear antigen (PCNA). The numbers of PCNA-positive basal cells and fibroblasts were counted, and the width of the junctional epithelium was measured. As a result, the numbers of PCNA-positive cells in the basal cells of the junctional epithelium were significantly lower in the brushed sides with the Ion-coated toothbrush (p<0.05, Wilcoxon-test). However, no significant differences were observed in the numbers of basal cells, fibroblasts, PCNA-positive fibroblasts and the width of the junctional epithelium between the two groups. In part 2, the inhibitory effect of plaque formation was evaluated. Ten healthy volunteers, aged 25-42, participated in this double blind study. Following professional toothcleaning, the participants brushed their teeth with one toothbrush for 3 days, and then changed to the other toothbrush for the next 3 days. At the end of each trial the inhibitory effect of plaque formation was evaluated. Dental plaque was scored using the Turesky-modified Quigley and Hein Plaque Index (Q & H) and the Debris Index of the Oral Hygiene Index (DI) by one examiner. The use of the Ion-coated toothbrush resulted in statistically significantly lower Q & H scores than the Nylon toothbrush (p<0.05, Wilcoxon-test). No significant difference was observed in DI scores. There were no side effects from either toothbrush. This study suggests that the new toothbrush has the potential to prevent periodontal disease.

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The purpose of this study was to describe the dental service distribution of endodontic treatment in private dental clinics in Japan. Dental care records registered in the national medical expenditure survey of 1980, 1983, 1985, 1990 and 1994 were used. The results were as follows, 1. The age groups in the dental care records changed from 30-39 years old (in 1980) to 50-59 years old (in 1994). 2. The mean age of patients receiving pulpectomy went up 9 years during the 14 years of the survey period, and that of patients receiving infected root canal treatment increased by 11 years. A remarkable increase was seen in the mean age of patients receiving endodontic treatment of single rooted teeth. 3. The 15 to 24 year age group continued to receive the highest number of pulpectomy of multi-rooted teeth over the 14 years. This suggests the need for new measures to prevent pulpectomy in molars. The elder group received single rooted teeth pulpectomy more frequently than the young group and the frequency increased year by year. 4. The distribution of pulpectomy of single rooted teeth peaked in 1990 while that of multirooted teeth decreased from 1985 to 1994. The frequency of infected root canal treatment of both single and multi-rooted teeth declined year by year.

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