This investigation was performed to find the variability of tactile sensation in examiners concerning adhesive force during probing. Six dentists, who had sufficient experience in epidemiological survey of carious lesions, pulled an explorer 120 times each. The explorer had been already inserted into a soft vinyl chloride plate as adhesive as carious pits or fissures. The tactile sensation of the subjects was classified as“discernibly adhesive”, “questionably adhesive”, and“not adhesive”. At the same time, the adhesive force of pulling the explorer was measured by the previously reported system.
From the frequency distribution of adhesive forces in the two groups, “discernibly adhesive”and“questionably adhesive”, the discriminating degree at each supposed adhesive force was calculated from sensitivity and specificity by the following formula.
Discriminating degree=Sensitivity×Specificity.
Then, the discriminating point of each examiner was taken to be the adhesive force at the maximum discriminating degree, indicating the level of discriminating ability of an examiner.
The discriminating points of the six examiners varied widely from 106.1-106.7 to 232.9-244.7g and this could be one of the factors which lead to low inter-examiner consistency in caries detection.
These results suggest that, in order to obtain the reproducible findings of carious lesions in an epidemiological survey, it is necessary to standardize an adhesive force in the detection of sticky carious pits and fissures.

View full abstract

The factors influencing the caries prevalence of children of three years of age were investigated using multivariant analysis.
The number of subjects were 543 who received the 3-year-old dental examination at Naruto Community Health Center in Tokushima from July to December in 1987. The caries-decisive factors examined were“Order of birth”, “Guardian”, “Kind of feeding”, “Nursing in bed”, “Frequency of between-meal eating”, “Place of between-meal eating”, “Amount of sweet snacks”, “Frequency of tooth brushing”and“Brushing by whom”and these factors were asked by questionnaire to mothers of children. Quantification types I and II were used as analytical methods. The former was applied to analyze the factors which had an influence on the dmft number, and the latter to analyze the factors which had an influence on the onset of dental caries.
The results were summarized as follows.
1. The factors strongly related to caries onset were“Place of between-meal eating”, “Amount of sweet snacks”and“Nursing in bed”, in order.
2. The factors strongly related to the number of dmft were“Guardian”, “Kind of feeding”and“Nursing in bed”, in that order. In“Guardian”, the category grandparents seemed to be a cariespromoting factor, and nursery school seemed to be an inhibitory factor.
3. A significant relationship between habitual tooth-brushing and caries onset or the number of dmft was not observed in this study.

View full abstract

The school dental health activity is practiced mainly in primary schools and junior high schools in Japan.
But health education throughout every stage of life is very important.
The purpose of this study was to reveal the oral health status and to consider school dental health activity in senior high schools.
The students of a high school (SAITAMA Pref.) were given a dental examination in 1982 and 1987.
The following results were obtained;
1) There was no change in the mean DMFT between 1982 and 1987. But the mean MT was decreased in 1987.
2) The treated teeth rate increased and the caries prevalence rate of anterior teeth decreased significantly.
3) The PMA index of the anterior teeth decreased significantly.
4) Almost all subjects need the hygiene instruction and about 90% of the subjects need prophylaxis.
5) There were positive correlations between CPITN and DI-S or PMAindex of the anterior teeth.
6) We conclude that CPITN is very useful for the dental management of high school students and we discuss its application in public dental health practices.

View full abstract

Synthesis of glucans and fructans from sucrose and adherence to glass by extracellular enzymes of two strains of oral Streptococcus salivarius were compared.
The enzyme of strain Y5 produced a large amount of sticky deposits on a glass surface whereas the nzyme of strain S2 formed a much smaller amount of fragile deposits. Products of the S2 enzyme consisted of nearly equal amounts of water-insoluble and water-soluble glucans and fructans (IG, SG, IF, SF). Major products of the Y5 enzyme were IG with a trace of SG and IF. Methylation analysis together with glucanase susceptibility tests revealed that IGs and SGs of both strains consisted of an α-1, 3-linked linear chain as a backbone sequence possessing α-1, 6- and α-1, 4-linked side chains of which both may constitute a single molecule or either may be located on different molecules. The IG of strains Y5 contained higher proportions of α-1, 3, 6 branch and α-1, 6-linked residues than the S2-IG. Adherence of IG to glass was markedly inhibited by the presence of glucanases. Dextranase shortened the α-1, 6-linked, and mutanase the α-1, 3-linked linear chains in IG and thereby reduced the amounts of IG products and lowered their molecular size, which resulted in less stickiness and/or insolubility of the products.
These results suggest that adhering deposits produced from sucrose by S. salivarius strains Y5 and S2 consist primarily of IG, and the α-1, 3- and α-1, 6-linked linear chains in IG, which are involved, respectively, in the water insolubility and adhesive property, act together to produce adherence of IG. Amounts of IG synthesized and relative proportion of the two linkages in IG determine the extent of adhesive mass formation. Thus, the glucanases would be effective to eliminate S. salivarius from various sites of the mouth, particularly the tongue dorsum and/or tooth surfaces.

View full abstract

The purpose of this study was to examine the prevalence of periodontal disease in an industrial population, and to evaluate the effectiveness of introducing the CPITN into the industrial dental health. The CPITN survey was performed on 126 persons aged between 20 and 64 using the WHO periodontal examination probe.
Modified visible plaque index (VPI) examination and a conventional oral examination for periodontal disease were also carried out, and a questionaire about subjective periodontal symptoms was given to all subjects.
From the results of the CPITN code, subjects requiring periodontal treatment (TN-II) were over 92% in all age groups. The severity of periodontal disease increased with age. There were correlations between the CPITN and the VPI, and between the CPITN and subjective symptoms.
As a result, it is recognized that in this industry, nearly all subjects require treatment for periodontal disease, including dental health education. The CPITN is a simple and efficient method to evaluate the periodontal status in industrial workers.

View full abstract

The present study was made to evaluate the possibility of caries prediction by simplified S.T. MEDIA.
A clinical trial of simplified S.T. MEDIA was carried out on 292 kindergarten children aged 5 years. Relationship between the simplified S.T. MEDIA scores and caries prevalence of primary teeth at 5 years of age, and caries incidence on permanent teeth for 5 years were assessed. The subjects were controlled under the school dental health program, which included topical fluoride application during the primary school period. Cohort observations were made for relationship between caries activity test score at 5 years of age and DMFT index from 1982 to 1987, according to the primary school of the subjects.
We investigated the correlation with each test score and deft index and/or deft rate at 5 years of age. A high statistical significance was shown for the relationship between each test score of simplified S.T. MEDIA at 5 years of age and the DMFT index in the 6 th grade.
We recognized a high correlation between the simplified S.T. MEDIA of caries activity test and the clinical findings, and we concluded that the simplified S.T. MEDIA has a high level of caries predictivity.
This test is effective in kindergarten or primary school, because of its simple and easy application.

View full abstract

In order to examine the reduction of dental caries in Japanese adolescents, 1368 male students aged 15 to 19 years were examined from 1975 to 1987. Because an irregular yearly variation in caries prevalence among the same age groups was observed, the method of 3-year moving average was used and statistically analyzed on a linear regression. From the yearly trend in the same age groups, peaks were shown in the mean DMFT of students 15 to 17 years of age in 1979 to 1981 and in the mean DMFS of students 15 to 19 years of age in 1979 to 1983. After the peaks, a statistically significant decrease in caries prevalence was found in the mean DMFT of students 15 years of age and in the mean DMFS of students 15 and 17 years of age. It is therefore concluded that a decline in dental caries in Japanese adolescents is clear and will be more evident in the near future.

View full abstract

[in Japanese]

View full abstract

The purpose of this investigation is to evaluate the validity of the Treatment Priority Index (TPI), compared with the Index of Handicapping Labio-lingual Deviations (HLD Index) for the assessment of malocclusion.
163 plaster models were obtained from the students of dental hygienist schools. This sample was examined according to the two indices. Each score was classified and analyzed with regard to the categories of malocclusion proposed by Björk. The means and cummulative percentage frequency distributions of both indices were compared in each category, and the results were as follows: In the incisal segment, both indices could distinguish maxillary protrusion, mandibular protrusion, open bite, deep bite, maxillary crowding, and mandibular crowding from normal occlusion. TPI could discriminate inversion of incisors and edge to edge, but HLD Index could not. Neither index could give reasonable values for diastema, midline displacement, maxillary spacing, or mandibular spacing. In the lateral and molar segment, both indices could distinguish maxillary crowding, mandibular crowding, and scissors bite from normal occlusion. TPI could distinguish mandibular spacing, distal occlusion, mesial occlusion, cross bite, and open bite, but HLD Index could not. Neither index could give reasonable values for maxillary spacing, tended to distinguish the minor anomalies of individual teeth, eruption, and alignment from normal occlusion better than HLD Index. Therefore, it is concluded that TPI is a good tool, although some types of malocclusion are not well distinguished from normal occlusion, so that some modifications must be made.

View full abstract

[in Japanese]

View full abstract