A survey was carried out to determine the relation between eating ability and physical activities/nutritional condition in institutionalised elderly persons with a mean age of 80.9yr. Assessment of eating ability was made using the test jelly method. Physical activities assessed were grip strength, equilibrium, and activities of daily living (ADL).
Those that kept their eating ability also retained physical activities, and vice versa. Therefore, eating ability is related to physical activities. However, nutritional condition was not affected by eating ability bacause of the good nutritional managemement in this nursing home.

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[in Japanese]

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An attempt was made to measure the volume of saliva in the mouths of 121 young subjects by the modified simple method of J.A. Wheatherell (1992).
Immediately after swallowing, a small volume of fluoride solution (F: 100ppm) was placed in the mouth. The subjects mixed this with their saliva and expectoated. The fluoride concetration of the expectorate was measured and the volume of saliva in the mouth at the time of fluoride administration was calculated from the fluoride dilution. The results are as follows;
The nonstimulated volume was 2.44 (mean) ±0.14 (S.E.) ml. The stimulated volume was 3.96 (mean) ±0.14 (S.E.) ml. Significant difference was observed between the unstimulated and the stimulated volumes (p<0.01). There was a significant positive linear correlation between the stimulated and unstimulated volumes (r=0.59; p<0.01).

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[in Japanese]

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Epidemiological analyses using the Ramfjord Periodontal Disease Index (PDI), Calculus Index (CI) and Plaque Index (PI) were performed on 881 mental retardates possessing one or more subject teeth at 15-48 years of age. They were among a group of 1107 subjects who were admitted to the Niigata Prefectural Institute of Total Training for the Mentally Retarded, Colony Niigata Shiroiwa-no-Sato, during the years 1971-1988.
(1) The PDI was 1.14-1.87 for the 15-19-year-olds in the periods 1971-1975, 1976-1981 and 1982-1988, and 3.88 and 3.09 for 45-54-year-old males and females in 1982-1988; it increased with the age of the newcomers of all 3 periods with regard to the time of admission. The CI also gradually increased with age, to 1.25 and 1.16 in 45-54-year-old males and females in 1982-1988, from 0.27-0.73 in 15-19-year-olds in the same 3 periods. The PI tended to increase very gradually with age, within the range of 1.19-1.83 both for males and females of the same age group and admission period settings.
(2) A decrease of PDI, CI and PI was found between males admitted in the years 1971-1975 and those admitted during 1982-1988. Though there was a difference in the 3 indices by gender and by intelligence quotient in 1971-1975, no difference was recognized in 1976-1981 and 1982-1988. Institutional and non-institutional comparison revealed no difference as far as a newcomer's history before the admission to the Colony was concerned.

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The purpose of this study was to examine plaque formation and dental caries occurrence in hamsters and rats fed a cariogenic diet containing confectioners' sugar and white sugar.
Eighty-one golden hamsters were divided into two groups: Group I fed on Diet-2000 containing confectioners' sugar and Group II fed on Diet-2000 containing white sugar. In hamsters of Group I there was more plaque accumulation and more destruction of molars by caries than in Group II.
One hundred sixty-five rats were divided into four groups: Group I fed on Diet-2000 containing confectioners' sugar; Group II fed on Diet-2000 containing white sugar; Group III fed on 6PMV containing confectioners' sugar; and Group IV fed on 6PMV containing white sugar. In Groups I and III there was more plaque accumulation than in Groups II and IV.
For dental caries in rats the outer third fissure and the inner third fissure were assessed. Rats of Groups I and II showed higher caries scores than those of Groups III and IV in both fissures. Rats of Group I had higher caries scores than those of Group II in the outer third fissure but the differences were not significant. There was no difference in the caries scores in the inner third fissure between Groups I and II.
In rats of Group III the caries scores were higher than in rats of Group IV in both fissures.

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[in Japanese]

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The purpose of this study was to examine the acid resistance of remineralized enamel after laser irradiation that could not be defined by microradiograph (MR). Forty-five human premolar enamel slabs were prepared for this study. The enamel slabs were ground down to about 400μm. Forty enamel slabs were divided into four groups, i, e., sound, demineralized (Dem), remineralized after laser irradiation (Lased) and remineralized (Rem) groups. The Other five slabs were used for MR. The Dem, Lased, and Rem groups were exposed to 0.1M lactic acid buffer (3.0mM Ca, 1.8mM P, 1.0% carboxymethylecllulose, pH 4.5, 37°C) for 12hours. The Lased group was irradiated with a Q switch Nd-YAG laser with 50J/cm² of total energy density. The Lased and Rem. groups were exposed to remineralizing solution (3.0mM Ca, 1.8m MP, 1.0% carboxymethylcelluse, 150mM NaCl, 3.0ppm F, pH 7.0, 37°C) for 10 days. The surface of the slabs for MR was divided into four, for all treatment. All slabs were exposed to 0.1M lactic acid solution (pH 4.5, 37°C, 5ml) for 12 hours. The dissolved calcium in the lactic acid solution was measured, and the disolved calcium per 10mm² was evaluated. The slabs for MR were sectioned their MRs were evaluated using the calculated mineral content. The Dissolved calcium of the Lased and Rem groups was significantly lower than in the Sound and Dem groups. Acid resistance for remineralization could be defined. However, there was no statistically significant difference between the lased and Rem group. The results were the same as the results of the MR evauation. The Lesions of the lased remineralized area were deeper than in unlased the remineralized area, but there was not statistic difference between these areas. It was thought that permeability of the enamel was increased by laser irradiation. However, the lesion depth was not related to the amount of dissolved calcium. It was thought that dissssolved calcium from the deep layer of the remineralized enamel after laser irradiation was not diffused easily because of reaction to each layer.

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The effects of the application of various fluorides on the remineralization and fluoride (F) incorporation of root surfaces with or without cementum were evaluated in vitro. Clinincally sound proximal root surfaces of premolars extracted from patients aged 9-14 years were used for experiments and divided into two categories: (1) a dentin group, where cementum was removed by abrasion, and (2) a cementum group, where the cementum was preserved. In both groups, two types of specimens were prepared: (1) sandwich specimens, for assessing mineral volume by a single section technique, and (2) block specimens, for the determination of F incorporation by biopsy.
After demineralization by immersion in 0.01M (for sandwiches, pH 5.1, 6mM Ca, 3.6mM P, 1% CMC, 37°C) or 0.1M (for blocks, pH 5.0, 3mM Ca, 1.8mM P, 1% CMC, 37°C) lactate buffer, specimens were treated with one of the following four fluorides during 14-day immersion in remineralizing solution (Rem solution: 3mM Ca, 1.8mM P, 150mM NaCl, 3ppm F, 1% CMC, pH 7.0, 37°C). The fluorides were APF solution (APF), APF gel (FG), F rinse solution (FR) and MFP dentifrice (FD). Control group (immersion in 3ppm F containing Rem solution only) and negative control group (immersion in F free Rem solution only) were also studied. APF and FG were applied for 4 minutes once just before remineralization, and FR and FD were applied for 1 minute every 24-hour remineralizing period. Sandwinch specimens were microradiographed before and after remineralization. The film density of lesions was convereted to aluminum thickness (Ta; μm) and the mineral volume of lesion (Ma; μm·μm) was defined as integrated values of Ta profiles. F content was determined by acid etch biopsy with 0.5M HClO₄.
The Results were as follows:
Remineralization of early root caries lesion in vitro was
(1) promoted by the application of fluorides, and accelerated more by the treatment with APF or FG than the treatment with FR or FD, and
(2) not significantly different between the cementum and the dentin groups.
(3) Cementum had no inhibitory effects on the remineralization of root surfaces.
F incorporation in remineralized root surfaces were
(1) different between various F treatments, and specimens treated with APF or FG showed significantly higher F uptake level, and
(2) greater in the cementum group than that in the dentin group and this fact indicates that cementum would be important tissue for demineralization and remineralization of root sufaces as a source of F ion supply.
According to the analysis of correlation coefficient, the degree of remineralization was obviously dependent on F incorporation in lesion surfaces.
In conclusion, these findings suggested that F application was effective for the remineralization of root surfaces and F incorporation into root surfaces did not depend on cementum. Thus, professional or self application of fluorides was considered to be higly suitable for the prevention of root caries in the elderly.

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[in Japanese]

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[in Japanese]

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The purpose of this study was to extract some factors from a 1.5-year-old dental health examination which affect the caries prevalence at 3 years of age in order to make dental health guidance more effective.
The subjects analyzed were 875 children who received a 3-year-old dental health examination at a certain public health center in Hiroshima City from April 1990 to March 1991. The dietary habits, tooth brushing habits and oral conditions at 1.5 years of age were surveyed and their relationships with dental health conditions at 3 years of age were examined.
The results were as follows.
1) The factors associated with caries prevalence in 3-year-olds were ‘Caries prevalence at 1.5 years of age’, ‘Order of birth’, ‘Regularity of snacks’, ‘Presently bottle feeding’, ‘Brushing by mother’ and ‘Drinking sweet beverages’.
2) The importance of giving dental health guidance to mothers before a 1.5-year-old dental health examination is discussed.

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The purpose of this study was to analyze the relation between oral conditions and caries activity tests (CAT) as a means of comprehending the oral conditions of outpatients.
We analyzed the data obtained from 116 patients (aged 11 to 71, who were examined by dental students and recalled from April, 1987 to March, 1988). The indices for multivariate analysis were age, sex, caries severity index (CSI), Ramfjord's periodontal disease index (PDI), missing teeth (MT), bleeding index (BI), debris index (DI), salivary flow rate (SFR), buffering capacity test (BCT), pH of saliva (SPH), lactobacillus colony count (LCC), and cariostat (CAR). The multivariate analysis was done with a program called ANALYST, which was developed for statistical analysis at the Educational Center for Information Processing, Kyushu University. The method of analysis was Kendall's ranking correlation.
A statistical significant correlation was shown between CSI and SFR, LCC, and CAR. The measurement of SFR was easy and effective for CAT in a general clinical examination. In addition, there was significant correlation between PDI and LCC and CAR. The examinations of LCC and CAR were useful as a means of comprehending oral conditions. Moreover, CSI had a significantly higher correlation to MT than to PDI. It was seen that the reason for missing teeth was still dental caries and then conditions that follow caries, such as pulpitis, apical foci, and so on.

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The interaction of sodium monofluorophosphate (MFP) with artificial plaque and the underlying enamel was investigated. Streptococcus mutans Ingbritt (serotype c) and Streptococcus sobrinus 6715 (serotype g) cells were grown on windowed human enamel blocks to form artificial plaque. Plaque-covered enamel and clean enamel samples were incubated anaerobically with 5 ppm (as F^-) of MFP or sodium fluoride (NaF) for 48 hr.
Fluoride concentration in the enamel was significantly increased in plaque-covered enamel in the presence of both MFP and NaF. More than 60% of the acquired fluoride from MFP in the enamel at a depth of 5μm was KOH-soluble fluoride. More fluoride was acquired from MFP in the enamel covered with the plaque of S. sobrinus 6715 than in that covered with the plaque of S. mutans Ingbritt.
Significant degradation of MFP was detected during the growth of S. sobrinus 6715 concomitant with the fall of broth pH around 5.4 within 48 hr incubation. Optimum MFP hydrolysis by S. sobrinus 6715 and S. mutans Ingbritt occurred at approximately pH 5.0, but no detectable MFP hydrolysis was found at alkaline pH. MFP hydrolyzing activity (MFPase) was sharply inhibited by low F^- concentration and was not activated by Mg²⁺. These data indicated that acid phosphatase, and not alkaline phosphatase, is responsible for MFP hydrolysis in mutans streptococci.

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