The purpose of this study was to examine the effect of topical fluoride applications on remineralization of the incipient lesion, in situ using quantitative light-induced fluorescence (QLF) and scanning electron microscopy (SEM). Forty-five bovine enamel disks were polished on the surface side. Artificial incipient lesions were produced by the immersion of specimens in a demineralizing solution for 1, 2, or 4 days. Four enamel specimens (1 untreated specimen and 3 demineralized specimens) were mounted in an intra-oral appliance and exposed to the oral environment of 5 healthy adult dentate volunteers. This study was performed in 3 phases, each lasting 7 days. In phase 1, subjects brushed their natural teeth 3 times per day with a dentifrice containing no active ingredients (PD group). In phases 2 and 3, participants brushed their natural teeth 3 times per day with a fluoride dentifrice (FD group). Acidulated phosphate fluoride gel was applied at the beginning of phase 3 (FD+APF group). Mineral loss and the microstructure of each specimen were determined using QLF on days 0, 3, 5, and 7, and SEM on days 0 and 7 in each phase. For delta Q (mineral loss from lesion) calculated using QLF, there were no significant differences among the 3 groups (PD, FD, FD+APF) in specimens demineralized for 1 and 4 days (p>0.05). For specimens demineralized for 2 days, a significant difference was observed between the PD and FD+APF groups on days 3, 5, and 7 (p<0.05). Microstructural observation revealed that deposits and pits were found on the surface of the specimens in the FD+APF group. In the FD group, the enamel crystals was not disordered. In conclusion, it appeared that APF application inhibits remineralization of the incipient lesion, which was demineralized to a certain degree.

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Sodium fluoride (NaF) and Sodium monofluorophosphate (MFP) are the most common anticaries ingredients used in fluoride dentifrices. The purpose of this study was to investigate the differences in effects of NaF and MFP on acid resistance of enamel. In this study, we employed conditions of fluoride treatment which simulated the daily use of fluoride dentifrices. The treatment of enamel specimens was carried out in solution of 950 ppmF NaF or MFP (2 times/day, 3 min/time, for 22 days). Following fluoride treatments, specimens were immersed in demineralizing solution (pH 4.5). The changes in lesion mineral contents, ΔZ, and the lesion depth (Ld) were assessed by quantitative microradiography. Enamel specimens treated with NaF showed significantly higher acid resistance than with MFP treatment (ΔZ: NaF<MFP, Ld: NaF<MFP). After 22-day fluoride treatment, specimens were demineralized (pH 4.0) for 6 days to investigate the structure of the acid-resistant layer. Microradiography revealed large differences in acid resistance between NaF and MFP. NaF-treated enamel showed acid resistant at only a superficial area. However, MFP-treated enamel had a thick and deep acid-resistant layer. Therefore, NaF could not penetrate into the enamel, while MFP penetrated deeper. The results showed that NaF and MFP made an interesting contrast concerning the investment of acid resistance under acidic conditions.

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In our previous report, we investigated the effect of tablets containing the protease, actinidin, extracted from Kiwifruit on the reduction of human tongue coating, and observed that protease tablets were effective in biochemical cleaning of the tongue. The purpose of this study was to investigate the effects of protease tablets on controlling the concentrations of volatile sulfur compounds, VSC, composed of hydrogen sulfide, methylmercaptan, and dimethylsulfide, in human mouth air, evaluated by a gas chromatograph with a flame photometric detector and an automatic sample injection device. Crossover and double blind studies were designed using 14 male adults. The concentrations of hydrogen sulfide, methylmercaptan, and total VSC decreased significantly with the protease tablets at 90 minutes after administration, whereas VSC concentrations were not changed on using the placebo tablets. The results of this study suggested that the use of the protease tablet was effective in controlling VSC concentrations in mouth air.

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The present study was carried out to assess the efficiency of the Community Periodontal Index (CPI) and Loss of Attachment (LA) as well as to evaluate periodontal disease progression for 5 years in community-dwelling elderly aged 70 years. A total of 313 selected subjects received a full mouth examination at six sites around the teeth for assessing gingival bleeding, dental calculus, periodontal pocketing, and the level of epithelial attachment. All data were modified in CPI and LA classification according to the WHO Oral Health Basic Method, 4th edition. Comparisons were made between full mouth recording and partial 10 index teeth recording to indicate the % of subjects and sextants according to each category of CPI and LA. As a result, 93.7% of subjects were diagnosed as CPI-1 or higher score by partial recording, while 97.4% were diagnosed as such by full mouth recording. The percentage of LA-1 and higher sextants by partial recording was 66.9%, as compared to 78.8% by full mouth recording. Sensitivities of CPI and LA between the two different recordings were also relatively reasonable, with 76.1% for CPI-3 and higher, and 84.9% for LA-1 and higher. The percentage of subjects with PD 6+mm increased up to 51.7%, while that for LA 9+mm was 43.2% for the five years. Our results may suggest that CPI and LA in an original 10 index teeth examination would be useful to promote a better oral health status for elderly people in monitoring periodontal disease progression.

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Oral malodor was measured using a portable sulfide monitor in 54 subjects in a home for mentally handicapped persons. The volume of tongue coating, DMF scores, usage of dentures, Plaque Index, and Gingival Index were also measured. In addition, the staff members of the home answered a questionnaire concerning the subjects' degree of disorder, requirement of assistance, self-ability of toothbrushing, and awareness of oral malodor. About 22% of subjects had been recognized as those with oral malodor. The mean concentration of volatile sulfide compounds (VSC) in their mouth air was 65.6 ppb. There was no significant difference in the VSC concentration between male and female groups. There was no significant relation between the VSC concentration and the requirement of assistance or the self-ability of tooth-brushing. Multiple regression analysis showed that the volume of tongue coating was significantly related to the VSC concentration. However, dental and gingival conditions were not related to the VSC concentration. It was concluded that the subjects in the home for mentally handicapped persons have similar or slightly higher levels of oral malodor compared to the average. Intensive oral care and easy access to dental services might contribute to the prevention of oral malodor.

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In Kagoshima University, medical examinations of students are carried out every year, while an oral health checkup has not been performed. A dental checkup was performed for 1,990 newly enrolled students in 2005. The subjects examined were 1,178 males and 751 females (attendance rate was 96.9%, and the average age was 20.5 years). The examination items and criteria were based on the recording sheet for periodontal disease examination issued by Kagoshima Kokuhoken Kyokai. The ratios of the students who had dental diseases or disorders except dental caries or periodontal diseases were as follows: disease of the mucous membrane, 0.4%; abnormalities in the form or number of teeth, 4.5%; temporomandibular joint disorders, 5.2%; malocclusion, 22.8%; others, 0.5%. The mean number of present teeth, filled teeth, and decayed teeth per student were 28.4, 4.2, and 0.8, respectively. The DMFT index was 5.0, which was lower than the value stated in the "Report on the Survey of Dental Diseases (1999)" by the Health Policy Bureau, Ministry of Health and Welfare, Japan (7.2 for subjects aged 15 to 19 years). The prevalence ofperiodontal disease was 24.3%.

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