Seishi Matsumura

Culture-based PCR analysis of plaque samples of Japanese school children to assess the presence of six common cariogenic bacteria and its association with caries risk.

The aim of the study was to assess the presence of six common cariogenic bacteria from Cariostat-inoculated plaque samples of Japanese elementary school children through PCR analysis and check its associations with caries risk testing the validity of Cariostat as a caries risk assessment tool. This epidemiological school-based study investigated plaque samples of 399 Japanese elementary school children. Assessed using the Cariostat, 48.2% of the children had high caries risk. DNA detection of Streptococcus mutans, Streptococcus sobrinus, Streptococcus salivarius, Lactobacillus casei, Lactobacillus plantarum, Lactobacillus fermentum and both S. mutans and S. sobrinus was seen in 65.2%, 24.1%, 69.7%, 17.5%, 7.8%, 19.3%, and 17.3% of the participants, respectively. Except for S. salivarius, the presence of all other investigated bacteria resulted in a statistically significant increase among the proportion of subjects with high caries risk. Caries risk assessed using Cariostat was significantly influenced by the presence of cariogenic bacteria. Being a selective medium for cariogenic bacteria, the Cariostat can be a useful and direct source of cariogenic bacterial DNA for PCR analysis while effectively assessing caries risk.

Cariogenic Bacteria and Caries Risk in Elderly Japanese Aged 80 and Older with at Least 20 Teeth

OBJECTIVES: To assess caries risk and check the presence of four commonly found oral cariogenic bacteria in “8020” achievers.

The relationship between body balance and occlusal balance of Japanese children during the deciduous dentition period

Abstract The relationship between childrens deciduous dentition occlusal balance and bodys gravity center movement was studied. The participants of this study were 128 children with Hellmans Dental Age IIA stage at a nursery school. The distance and the area of gravity center movement (GCM) when the participants had their eyes-opened and eyes-closed were measured with automatic posture analytical devices. Occlusal abilities including occlusal contact area, average pressure, maximum occlusal pressure, occlusal force and occlusal balance were measured with the Dental Prescale® system. Analysis of occlusal balance was determined by separating the middle group (|x|≤5mm) from the deflection group (|x|>5 mm) based on the position of occlusal balance center. A significant difference was found between the occlusal balance of the middle group (n=96) and the occlusal balance of the deflection group (n=32) in the distance and area of gravity center movement with eyes-opened and closed. The distance and area of gravity center movement of the middle group was less than that of the deflection group. Analysis of body balance was determined by the good balance group and bad balance group based on the GCM area with eyes-closed. A difference was found between the good balance group and the bad balance group in the occlusal contact area and occlusal force. The occlusal contact area and occlusal force of good balance group were higher than the bad balance group. Body and occlusal balance was observed to have some interactive influence during Hellmans Dental Age IIA period. The influence of occlusal balance on body balance is much stronger and obvious than the influence of body balance over occlusal balance. Occlusal balance can influence on the body balance most of the time while body balance can sometimes influence on the occlusal balance.

Risk behaviors and its association with caries activity and dental caries in Japanese children

Abstract The aim of this study was to assess risk behaviors and its association with caries activity and dental caries in Japanese children. The subjects were 392 young Japanese children who underwent dental health check-up at 18, 30 and 42 months of age. Oral examinations, Cariostat tests and dental health questionnaires were carried out at each time. The caries prevalence of children was 1.5% at 18 months, 9.9% at 30 months and 28.1% at 42 months. Caries activity based on the Cariostat scores of children was correlated with caries status (caries-free/carious) at 42 months. In children with caries during each examination period at 42 months, eating snacks while playing was ranked as the most important behavioral risk ( P P P P P P P

Viability of the Cariostat® medium as a source of DNA for further analysis through polymerase chain reaction

Abstract This simulation study was carried out to analyze and evaluate Cariostat-inoculated samples through a conventional PCR protocol specific for Streptococcus mutans strains and also for the purpose of establishing acceptable storage conditions for Cariostat-inoculated samples in cases in which optimal storage conditions are not feasible. A reference strain of Streptococcus mutans (ATCC 25175) was used in the study. The samples were subjected to different inoculation, incubation and storage conditions, and bacterial viability was checked through a conventional PCR technique and by assessment of colony growth on different agar media. Band detection of all samples incubated for even up to 120 hours at 37°C was still possible, indicating less DNA degradation. Samples stored at −20°C yielded results closest to those of samples incubated normally (without storage), followed by samples stored at 4°C and then samples stored at room temperature. The difference in these results, however did not influence the quality of DNA to an unsatisfactory level. For bacterial viability through agar plating, even if there were no more viable growth on the plates, band detection from strains inoculated and stored in Cariostat was still possible. From these results, we conclude that samples stored under various conditions can be further analyzed using DNA extraction protocols for conventional qualitative PCR amplification.

Presence of Streptococcus mutans or Streptococcus sobrinus in Cariostat®-inoculated plaque samples from Japanese mother-child pairs

Abstract The aim of this study was to determine the presence of Streptococcus mutans or Streptococcus sobrinus in Cariostat-inoculated plaque samples obtained from Japanese mother-child pairs through a conventional PCR technique and to establish the presence of these bacteria and caries risk. Oral examination and caries risk assessment using the Cariostat ® were carried out on 168 children, aged 6–31 months, and their mothers. The presence of S. mutans and S. sobrinus in Cariostat-inoculated plaque samples was checked through PCR and tested for relevance with caries risk. A significant correlation ( P S. mutans or S. sobrinus in plaque samples from their children in the 19–31-month-old age range. However, no significant relationship found between the presence of either strain in the plaque of younger children (6–18 months) and caries risk of mothers. Likewise, high caries risk was seen in 49.1% of the 19–31-month-old children of highrisk mothers ( P P S. mutans and S. sobrinus in plaque samples obtained from mothers and their children through conventional PCR techniques.

Postural stability and occlusal status among Japanese elderly

BACKGROUND There are still no data available on the relationship between postural stability and occlusal status among the elderly. OBJECTIVES To examine relationships between postural stability and occlusal status through a cohort study among elderly Japanese. METHOD Oral examination, occlusal status, postural stability and a questionnaire were conducted and given to 87 community-dwelling Japanese at enrolment. RESULTS The average occlusal pressure of the female group was statistically higher than the male group while average occlusal pressure and postural stability length were lesser in the group with more remaining teeth. Postural stability area and number of remaining teeth showed statistically significant correlations. Postural stability length was lesser in the group with strong occlusal force. Furthermore, the number of decayed teeth was fewer in the good hygiene group. CONCLUSIONS This study identified a close relationship between occlusal status and postural stability of Japanese older individuals. Occlusal hypofunction was observed more in those with occlusal problems, and a decrease in their occlusal functions resulted in postural instability.

In vitro antibacterial activities of Scutellaria baicalensis Georgi against cariogenic bacterial

Abstract Scutellaria baicalensis Georgi has been used for thousands of years in traditional Chinese medicine practice for several purposes. It possesses several biological activities such as anti-oxidative, anti-inflammatory, antibacterial and antiviral activities. Although the antibacterial activity of Scutellaria baicalensis Georgi has already been demonstrated, little is known about its antibacterial activity against oral pathogens in vitro . Therefore, the aim of this study is to evaluate the antibacterial activity by six different kinds of Scutellaria baicalensis Georgi extracts in vitro . The three kinds of bacterial strains were used as follows: Streptococcus mutans ATCC 25175, Streptococcus sobrinus ATCC 33478 and Streptococcus salivarius ATCC 7073. The antibacterial activity was determined by the agar diffusion method, and the zones of growth inhibition were measured. The MICs and MBCs were determined by the broth dilution and agar dilution methods. The bactericidal activity was determined by time-kill assay. In all the Scutellaria baicalensis Georgi solvent extracts, except for water and ethyl acetate, a significant inhibitory activity was observed. The acetone and 80% ethanol, and the ethanolic extracts showed higher activity than the methanol extracts and produced inhibition zones ranging from 7.11±0.18 to 14.79±1.02mm in diameter at a concentration of 750μg/disk. The MIC value of the Scutellaria baicalensis Georgi extracts ranged from 125 to 1,000μg/m l . The MBC values for different strains and extracts ranged from 250 to 2,000μg/m l . Thus, Scutellaria baicalensis Georgi would be useful for the suppression of oral pathogens, and has the potential for use in the prevention of dental caries.

Risk behaviors and their association with presence of S.mutans or S.sobrinus and caries activity in 18-month-old Japanese children

Abstract The purpose of this study was to investigate risk behaviors associated with the presence of S. mutans or S. sobrinus and caries activity. The subjects were 448 mother-child pairs who underwent dental health examinations between February 2004 and November 2004 when the children were 18 months old. Caries activity was assessed by the Cariostat test. The presence of S. mutans and S. sobrinus was detected using PCR techniques. Questionnaires regarding risk behaviors were completed by the mothers. A statistically significant correlation was found for the detection of S. mutans and/or S. sobrinus in children and mothers ( P P P P P P P P P

Caries activity test in Mongolian and Japanese children

Abstract The main objective of this study was to investigate the relationship between a caries activity test (CAT21 Test), and caries status. The subjects of this study were 419 preschool children, of Okayama City, Japan and, of Ulaanbaatar City, Mongolia. In all, subjects were examined for dental caries using a mouth mirror and probe. Then buccal plaque samples were obtained, incubated at 37°C for 48 hours, and scored as per the manufacturers instructions for the Cariostat method. The following results were obtained: 1.The caries prevalence and mean deft of the two subjects was 55.0% and 3.2 for Japanese, so 92.4% and 6.6 for Mongolians, respectively. 2.Results of the CAT21 Test score distribution are as follows: 14% of the Japanese, 7.6% of the Mongolians had a CAT score of 0 (very low risk), 38% of the Japanese, 12.4% of the Mongolians had a 1.0 (low risk), 16.3% of the Japanese, 17.9% of the Mongolians had a 2.0 (middle risk), 25.5% of the Japanese, 36.6% of the Mongolians had a 3.0 (high risk), and 6.2% of the Japanese, 25.5% of the Mongolians had a 4.0 (very high risk) score. 3.There was a statistically significant difference in the CAT21 Test scores and dental caries indices of Japanese and Mongolian preschool children (ANOVA P From these results, it was suggested that the CAT21 Test is useful in clinical application