Water fluoridation invalves the adjustment of the fluoride ion content of a domestic municipal water supply to the optimum physiologic concentration to provide maximum protection against dental caries and enhance the appearance of teeth, with the minimum risk of enamel fluorosis. Fluoridation has been established as the most efficient, effective, reliable, and inexpensive means for improving and maintaining oral health. Fluoride (fluorine) should be positioned as a nutrient essential for the formation of sound teeth and bones, just as calcium, phosphorus, and other elements obtained from food and water, prior to the introduction of water fluoridation. Fluoride (fluorine) has already been mentioned in the national standard of essential nutrients in the European Union and United States. Fluoride (fluorine) is expected to be referred to in the Japanese standard of essential nutrients, and water fluoridation will be introduced in Japanese communities.

View full abstract

 The period of junior high school is a time when students face changes both physically and mentally with the development of secondary sex characteristics, which also influence their emotional stability. They are, however, less conscious about their health since their physical resistance strengthens. The aim of this study was to gain an insight into the consciousness between consultation behavior and awareness of various diseases and symptoms, including dental diseases. A questionnaire survey was conducted and analyzed for junior high school students.
 The survey showed that the students considered the necessity of medical care for cardiac disease, otitis media, and dental caries, but not for gingivitis, rhinitis, and myopia. With regard to the relation between subjective symptoms and consultation behavior, they considered that the items: "Found a hole in my tooth" and "Terrible tooth aches" are much more serious than "Vomiting" and "Got a fever of 38 degrees", which require medical treatment. They, however, considered that the items: "Bleeding on toothbrushing", "Stuffy nose", and "Runny nose" do not require medical treatment.
 This survey revealed that the students considered tooth cavities as a serious problem, although more than half of them had no experience of decay accompanied by pain and discomfort. In addition, they were totally unaware of the presence of caries until pointed out in a school regular health examination. Therefore, in order to improve the oral health of students, it is important to design a strategy which promotes students' consciousness of their own oral health and checking their mouth carefully on a regular basis. In addition, it is also important to provide appropriate information and education promoting voluntary awareness of the difference between healthiness and illness.

View full abstract

 The purpose of this study was to evaluate the effects of chewing gum containing phosphoryl oligosaccharides of calcium (POs-Ca) and green tea extract fluoride on the activity of early caries lesions in 6〜7-year-old children. Subjects were 92 elementary school students. Chewing gum containing POs-Ca was given to 50 subjects (control group), and chewing gum containing POs-Ca and green tea extract fluoride was given to 42 subjects (F group). All subjects chewed two tablets of gum for 5 minutes once a day after lunch. Quantitative light-induced fluorescence (QLF) images of the occlusal surface of the 1st permanent molars were acquired using QLF equipment. QLF images were then examined to detect early caries lesions. The detected early caries lesions were analyzed in order to determine the volume of demineralization. The activity of early caries lesions was classified as progressing, arrested, or recovering based on changes in the results of QLF analysis over time. Chewing gum use was continued for one year, and examinations were repeated at 6-month intervals. QLF analysis of the activity of early caries showed that 32% of early caries lesions recovered in the control group, whereas 46% of lesions recovered in the F group (p<0.05). This suggests that chewing gum containing POs-Ca and green tea extract fluoride recovers early caries lesions on the occlusal surface of 1st molars in 6〜7-year-old children more effectively than chewing gum containing POs-Ca.

View full abstract

 The objective of this study was to analyze various factors related to dental caries in Japanese infants. Subjects study comprised infants living in a rural area of the northern part of Honshu Island (n=162). They received dental check-ups provided by the local government when they were 18 months, 2 years, and 3 years old.
 In the follow-up studies, intraoral examinations, interviews, and mutans scores were recorded using the Dentocult-SM^TM at dental check-ups, performed to identify factors affecting the number of decayed, missing, and filled permanent teeth (DMFT) at the age of 11 years.
 Contingency table and logistic regression analyses revealed that DMFT scores at 11 years of age were closely associated with the caries incidence in 2 and 3 year olds, brushing teeth by a carer, eating snacks, having a mentor during the daytime, and Dentocult-SM^TM scores.
 Risk factors for developing dental caries were suggested, and their screening in infants is essential to prevent permanent tooth caries.

View full abstract

 We conducted this questionnaire survey (December, 2010) to clarify the working situations of female dentists at schools of dentistry, dental colleges, and graduate schools, and the availability and use of support systems for them. Responses from 28 schools were analyzed. The percentages (%) describe the rate of institutions using support systems "now (2010)" and "until now", while those answering "unknown" were excluded.
 Paid full-time female dentists at schools of dentistry and dental colleges accounted for 17% of all dentists, and this figure significantly decreased with career progression: 28% of assistant professors, 15% of instructors, 7% of associate professors, and 2% of professors. The rate of utilizing the "maternal leave" system, available at all institutions, was more than 90%, and the users were mostly tenured during their leave (27 institutions). Although "reduced-hour working positions for childcare (full-time workers)" were provided for women (27 institutions), the rate of utilization remained low (24% now and 40% until now). A limited number of institutions had "on-site childcare facilities (11 institutions)"and "back-to-work support systems (2)", both of which were fully utilized. However, the rates remained low as a whole (28 and 4 now and 35 and 7% until now, respectively). A "system to provide substitutes for those on leave" was available at only a small number of institutions (7) and was scarcely used (7% now and 11% until now). No work-sharing system was available at any institution. Public institutions had better support systems of "on-site childcare" and "substitutes" than private ones. Women's career development requires the reform of social awareness as well as improvement in the social environment with more diversified working styles. It is essential to prepare a better environment to ease the burden on women, users of the systems, and the people around them.

View full abstract