Salivary microbiome in children with Down syndrome: a case-control study.

BACKGROUND: Down syndrome (DS), a most frequently occurring genetic disorder, is associated with oral morphological abnormalities and higher incidence rates of oral diseases. Recent studies have analyzed the oral microbiome to elucidate their relationships with oral diseases and general health; however, reports on the oral microbiome in individuals with DS are scarce. This study aimed to characterize the oral microbiome in children with DS. METHODS: A total of 54 children aged 1-13 years were enrolled in this case-control study. Of these children, 27 had DS (Case: DS group) and 27 were age-matched healthy children (Control: ND group). Saliva in the oral cavity was collected with a swab, cultured, and tested for cariogenic and periodontopathic bacteria by quantitative polymerase chain reaction (qPCR) detection, and the salivary microbiome was analyzed using next-generation sequencing. The student's t-test, Fisher's exact test, Mann-Whitney U test, and permutational multivariate analysis of variance were used for statistical analysis. RESULTS: Results of culture and qPCR detection tests for cariogenic and periodontopathic bacteria showed no significant differences in the detected bacteria between the DS and ND groups, with the exception of a significantly higher detection rate of Candida albicans in children with DS with mixed dentition. A comparison of the salivary microbiomes by 16S sequencing showed no significant difference in α diversity; however, it showed a significant difference in ß diversity. Children with DS had a higher relative abundance of Corynebacterium and Cardiobacterium, and lower relative abundance of TM7. CONCLUSIONS: This study provided basic data on the salivary microbiome of children with DS and showed the microbiological markers peculiar to children with DS. However, further research to identify the relationship with oral diseases is warranted.

Evaluation of a dysphagia screening system based on the Mann Assessment of Swallowing Ability for use in dependent older adults.

AIM: Dysphagia is common in dependent older adults. Thus, a method of evaluating eating and swallowing functions that can be used to diagnose and manage dysphagia in a simple and robust manner is required. In 2002, the Mann Assessment of Swallowing Ability (MASA) was introduced to identify dysphagia in acute-stage stroke patients. As the MASA enables easy screening, it might also be applicable to dependent older adults if appropriate MASA cut-off values and the most useful assessment items could be determined. In the present study, we attempted to determine suitable MASA cut-off values, and the most useful assessment items for predicting aspiration and pharyngeal retention in dependent older adults. METHODS: Using the MASA, we evaluated the eating and swallowing functions of 50 dependent older adults with dysphagia. All of the patients also underwent videoendoscopic-based swallowing evaluations to detect aspiration and pharyngeal retention. The participants' characteristics and the utility of each assessment item were compared between various groups. Using the patients' videoendoscopic findings as a reference, receiver operating characteristic curve analysis was carried out to determine appropriate cut-off values for predicting aspiration and pharyngeal retention in dependent older adults. RESULTS: The optimal MASA cut-off values for predicting aspiration and pharyngeal retention were 122 points and 151 points, respectively. A total of 17 of the 24 clinical items assessed by the MASA were found to be associated with aspiration in dependent older adults. CONCLUSIONS: The MASA is a useful screening tool for evaluating eating and swallowing functions in dependent older adults. Geriatr Gerontol Int 2017; 17: 561-567.

Longitudinal Evaluation of Community Support Project to Improve Oral Function in Japanese Elderly.

Change in oral function was evaluated longitudinally in elderly persons participating in an Exercises for Healthy Oral Function program implemented as part of the Long-Term Care Prevention Project. The participants comprised high-risk and healthy persons aged 65 yr or over. A questionnaire was used to classify them into two groups ('every day or sometimes' or 'rarely') at the end of the study for a comparison of change in repetitive saliva swallowing test (RSST) scores and oral diadochokinesis between 3 time points: at before, at immediately after, and at 1 yr after completion of the program. The average RSST score showed a decrease at 1 yr after intervention, but the difference was not statistically significant. Oral diadochokinesis showed a significant increase for all syllables upon completion of the program compared with at the beginning. This was followed by a significant decrease at 1 yr later compared with at the time of completion in the 'rarely' group for all syllables, but not in the 'every day or sometimes' group. In addition, the number of repetitions was significantly lower in the 'rarely' group than in the 'every day or sometimes' group for all syllables at 1 yr after completion. The results of the present study suggest that Long-Term Care Prevention Projects are necessary to maintain and improve oral function.

Comparison of the oral health problems and behavior of male daytime-only and night-shift office workers: An Internet survey.

OBJECTIVE: The aim of this study was to compare the oral health problems and behavior of full-time male daytime-only and night shift office workers. METHODS: The participants were recruited by applying screening procedures to a pool of Japanese registrants in an online database. During the period of 20 February 2015 to 11 March 2015, participants were asked to complete a questionnaire about their oral health. A total of 325 daytime-only workers and 351 workers who sometimes worked night shifts, ages 30 to 69, were analyzed in this study. RESULTS: Overall, the mean number of teeth of the night shift workers was lower than that of the daytime-only workers (p=0.002). When analyzed by age group, a significant difference was seen in the 50-69 age group (p=0.016). The percentage of night shift workers with decayed teeth was higher than that of the daytime-only workers (p<0.001). The night shift workers were more likely to report gingival bleeding (p=0.015) and stomatitis (p=0.025) than the daytime-only workers. The percentage of night shift workers reporting frequent brushing behavior was lower than that of the daytime-only workers (p=0.040). The independent variables found to correlate significantly with tooth decay were night shift work (OR, 1.79; 95% CI, 1.20-2.67), current smoking habit (OR, 1.66; 95% CI, 1.13-2.46), and BMI of ≥25 (OR, 1.56; 95% CI, 1.02-2.39). CONCLUSIONS: These results indicate a relationship between night shift work and oral health problems. Night shift workers may require additional support for oral health maintenance.

Comparison of Dental Explorers and CPI-probes in Diagnosing Dental Caries.

The primary aim of the present study was to compare efficiency in detecting suspected caries requiring observation (CO) and decayed teeth (DT) between dental explorers and Community Periodontal Index (CPI)-probes in school dental examinations and evaluate the effect of their respective use on Decayed, Missing, Filled Teeth (DMFT) Index scores. A total of 126 elementary and high school students were examined. All the clinical findings were obtained by a pair of trained dentists examining each student at routine annual school dental examinations. A dental explorer or CPI-probe and dental mirror were used for the examination. One dentist used the dental explorer, while the other used the CPI-probe. The choice of which instrument to use by the first dentist to examine the student was made at random. A comparison of the explorers and CPI-probes revealed that the numbers of patients and permanent teeth classified as CO were greater with the former in 6th-grade elementary and high school students (p<0.05). The Kappa value for CO and DT was 0.560 for 6th-grade elementary school and 0.846 for high school students. All DMFT scores were higher with the explorers than with the CPI-probes in the 6th-grade elementary school students. No significant difference was observed between the explorers and CPI-probes in any of the DMFT scores in any group, however. The present results indicate that as long as the low rate of caries in Japanese school children is maintained, the epidemiological data on this disease should not show any significant change if a CPI-probe is used instead of an explorer in school dental examinations.

Cohort study on incidence of coronal and root caries in Japanese adults.

The purpose of this study was to investigate the incidence of coronal and root caries in participants aged 20-59 years in Japan. The participants comprised 118 men and 23 women undergoing a re-examination 5 years after an initial examination. Lesions were classified as gingival recession, decayed root caries, or filled surfaces. The rates of incidence of coronal caries over the 5 years were 87% in women aged 20-29 years, 77% in men aged 20-29 years, 62% in men aged 30-39 years, 64% in men aged 40-49 years, and 60% in men aged 50-59 years. The rates for those observed to be at risk for the incidence of root caries were 25% for women aged 20-29 years, 16% for men aged 20-29 years, 11% for men aged 30-39 years, 43% for men aged 40-49 years, and 35% for men aged 50-59 years. The distribution for the number of new coronal and root caries lesions was 68.8% and 24.1%, respectively. Univariate logistic regression analyses for new coronal caries revealed that the risk factors were age group at baseline (OR=0.702, p=0.0440), number of coronal decayed and filled surfaces at baseline (OR=2.893, p=0.0107), and number of sound teeth at baseline (OR=3.381, p=0.0013). Moreover, univariate logistic regression analyses for new root caries revealed that the risk factors were age group at baseline (OR=1.787, p=0.0039), presence or absence of gingival recession at baseline (OR=3.288, p=0.0062), and presence or absence of root decayed and filled surfaces at baseline (OR=11.00, p<0.0001). It was concluded from these results that the target of caries prevention in adults should not only be focused on root surfaces, especially in those aged 40 years or over, but also on the coronal surfaces of the dentition in those in their twenties.

Monitoring caries risks before the window of infection and later caries increment: a caries prediction study on rapid detection of Streptococcus mutans using monoclonal antibodies.

A new semi-quantitative enumeration system has been developed for the detection of Streptococcus mutans in saliva. Using two kinds of species-specific monoclonal antibodies, this system can quickly detect salivary S. mutans within 30 min and classify the results into three levels. The aim of this study was to evaluate the potential of this test kit in determining risk for the development of caries. Saliva samples collected during a compulsory dental examination from 56 children aged 18-months were tested. The children were classified into 3 groups according to the level of salivary S. mutans determined. After 18 months, 36 of the children underwent a second examination to investigate whether there was a correlation between salivary S. mutans level at the first examination and subsequent increment in caries. The results showed a good correlation between the two. This indicates that salivary S. mutans level before the window of infection is an indicator of caries risk and can be quickly detected using this test kit. This rapid test should be particularly useful in assessing risk of future caries in very young children.

Trends in percentage of postgraduate dental trainees at dental clinics.

A facilities-group system designed to provide clinical training at dental clinics was developed after postgraduate clinical training became mandatory for dentists in Japan in 2006. As a result, there has been a steady increase in the number of dental clinics collaborating with dental school hospitals under this program. A larger number of dental clinics have also been designated as single-system facilities, program management facilities or collaborating facilities. However, it remains to be determined whether this increase in the number of dental clinics designated as clinical training facilities has led to an increase in the amount of training offered. Therefore, the purpose of this study was to investigate trends in the percentage of postgraduate dental trainees at dental clinics between fiscal years 2006 and 2010. The results showed no significant correlation among (1) the percentage of dental clinics designated as single-system collaborating facilities, (2) the percentage of training programs at dental clinics, and (3) the proportion of training program recruitment offers by dental clinics compared to the total number of recruits. These findings showed that increasing the number of collaborating dental clinics did not lead to an increase in the amount of clinical training at dental clinics. The findings also suggest that increasing the number of single-system or program management dental clinics is important in promoting clinical training at dental clinics.

Does mandatory postgraduate clinical training worsen geographic distribution of dentists in Japan?

Postgraduate clinical training for dentists has been mandatory in Japan since 2006. Hirata et al. reported that the geographic distribution of postgraduate dental trainees by prefecture in 2006 was worse than that of practicing dentists. This suggests that the postgraduate clinical training system could intensify the problem of distribution of dentists. In this study, therefore, we reviewed the geographic distribution of postgraduate dental trainees and practicing dentists between 2006 and 2010 in detail by city, ward, town and village by using the Lorenz curve and Gini coefficient. The results showed that while there was no significant worsening of geographic distribution of postgraduate dental trainees, the distribution of practicing dentists continued to deteriorate. A number of reasons may explain these findings: the clinical training system is based on a one-year employment contract, and dentists subsequently relocate as driven by the market; and geographic distribution among cities, towns and villages has worsened as a result of the merger of municipalities. The geographic distribution of practicing dentists is expected to deteriorate further if the number of dentists takes a downward turn in the future. Therefore, it is necessary to continuously review the distribution of postgraduate dental trainees.

Factor analysis on implementation of domiciliary dental care in Metropolitan Tokyo.

The need for domiciliary dental care has increased with the aging of Japanese society. The Tokyo Metropolitan Government and Tokyo Dental Association conducted a survey of dental institutions within Tokyo in order to clarify which factors influenced implementation of domiciliary dental care by dental institutions. The proportion was significantly higher in (1) dentists in their 50s or older, (2) those working in cooperation with primary care physicians, (3) those providing dysphagia rehabilitation, (4) those who give information on prevention of aspiration pneumonia, (5) those who attended training on medical or domiciliary dental care for the elderly in need of nursing care, and (6) those who attended training workshops and seminars provided by the Tokyo Dental Association in 2010. In the logistic regression analysis, a significant odds ratio was obtained for the same items, excluding age. Attendance at training on medical or domiciliary dental care for the elderly in need of nursing care had the highest odds ratio. Those who attended any kind of training course implemented domiciliary dental care significantly more often. Training conducted by the Tokyo Metropolitan Center for Oral Health of Persons with Disabilities, Tokyo Dental Association, and local dental associations showed a significant odds ratio, with the highest by the Tokyo Dental Association. Traditionally, education on domiciliary dental care in the elderly is not provided at the college level. The present results indicate the importance of educating students with regard to the unique challenges such work poses. Attending seminars hosted by the Tokyo Dental Association also significantly influenced implementation of domiciliary dental care. This seems to be an important result, suggesting the effectiveness of training provided by dental associations with regard to the promotion of domiciliary dental care. This indicates the need for dental associations to provide such training throughout Japan.

Effect of zeta potentials on bovine serum albumin adsorption to hydroxyapatite surfaces.

The aim of the present study was to examine the adsorption of bovine serum albumin (BSA) to hydroxyapatite surfaces by means of zeta potential. The electrophoretic mobility of both hydroxyapatite and BSA were negative, with BSA itself less negative than hydroxyapatite. The zeta potential of the surface of BSA-adsorbed hydroxyapatite was significantly more negative than that of hydroxyapatite alone (p<0.0001). The BSA histogram indicated two negative peaks, and the zeta potential of BSA-adsorbed hydroxyapatite also showed two similar negative peaks. These results suggest that BSA adsorption to hydroxyapatite surfaces is related to electrostatic interaction.

Evaluation of a Japanese "Prevention of long-term care" project for the improvement in oral function in the high-risk elderly.

AIM: The purpose of this study was to analyze the improvement in oral function and environment in high-risk elderly persons participating in a program to improve oral function organized by their local government. METHODS: Participants comprised 36 high-risk elderly and the mean age was 77.11 ± 7.24 years. The program involved training sessions carried out five or six times every 2-3 weeks for 3 months. Oral function and environment was evaluated before and after the program. The research period extended from 2008 to 2010. RESULTS: The effects of intervention were clearly observed in oral diadochokinesis score in the high-risk elderly. Persons with a lower repetitive saliva swallowing test (RSST) and oral diadochokinesis score before intervention showed a tendency toward even greater improvement. No significant changes were observed in saliva secretion or total amounts of Streptococcus mutans, Lactobacilli, Candida or total microorganisms. CONCLUSIONS: The effects of intervention were clearly recognized in regards to oral diadochokinesis. Improvement in RSST and oral diadochokinesis scores was marked in those persons showing a lower number of articulations before intervention.

Factors associated with root surface caries in elderly.

The purpose of this study was to determine the risk factors for root surface caries in the elderly and to evaluate the factors associated with gingival recession, one of the main risk factors for root surface caries. A total of 153 elderly people (35 men, 118 women) aged between 60 and 94 years (73.5+/-7.5 years) were surveyed. All participants were relatively healthy elderly who did not need special care in their daily lives. The survey was conducted in Chiba prefecture, Japan, and oral examinations and a questionnaire with face-to-face interviews were also carried out. Correlation analysis revealed that number of present teeth (p<0.001), gingival recession (p<0.001), bleeding on probing (p<0.001) and presence or absence of dentures (p<0.05) were significantly correlated with number of root surface caries. Stepwise multiple linear regression analysis for root surface caries revealed that the risk factors for increasing numbers of teeth with root surface caries were number of teeth with gingival recession (p<0.0001), bleeding on probing (p=0.0017) and self-reported dry mouth (p=0.0454). Sex (p<0.05), number of present teeth (p<0.001), bleeding on probing (p<0.01), the presence or absence of systemic disease (p<0.01), dentures (p<0.01), drinking alcohol (p<0.01) and smoking (p<0.01) were significantly correlated with amount of gingival recession by correlation analysis. Moreover, the risk factors for increasing number of teeth with gingival recession were living in an institution (p=0.0244), number of present teeth (p<0.0001) and smoking (p=0.0037), as determined by stepwise multiple linear regression analysis for gingival recession.

A study of occlusion in elderly Japanese over 80 years with at least 20 teeth.

OBJECTIVES: The purpose of this study was to identify the occlusal status of elderly Japanese over 80 years with at least 20 teeth. MATERIALS AND METHODS: The study enrolled 76 elderly Japanese (44 male, 32 female) with a mean age of 82 years and an average of 25.7 remaining teeth. The study consisted of intra-oral examination, intra-oral and facial photographs, radiographs and impressions for study casts. RESULTS: No gender difference was observed in age or number of remaining teeth. Anteroposterior occlusal relationship was characterised by maxillary protrusion in 67.6%, acceptable overjet in 31.0%, and anterior crossbite in 1.4%. Vertically, deep bite was noted in 33.8%, acceptable overbite in 64.8%, and open bite in 1.4%. Most of the subjects had either Angle class I (68.4%) or class II (25.7%) canine relationship. Only 3.9% of the subjects had upper anterior crowding. Lower anterior crowding was observed in 23.7%, but tended not to be severe. CONCLUSION: These results indicate that Japanese who attained the goal of '8020' have a relatively good occlusion.

Fluoride analysis of foods for infants and estimation of daily fluoride intake.

The mean daily fluoride intake in infants was estimated on the basis of their intake of commercial foods for infants in Japan and evaluated in order to establish the effectiveness and safety criteria for water fluoridation, which is practiced as a preventive measure for dental caries suitable in life stages from children to the elderly. Based upon the intakes of foods for infants, the mean daily fluoride intake was estimated to be 0.166 mg in infants aged 3-4 months, 0.202 mg in those aged 5-6 months, and 0.266 mg in those aged 7-8 months. The mean daily fluoride intake per kg of body weight at these ages was in the range of 0.023-0.029 mg/kg, which was about half of the standard daily fluoride intake for infants and children advocated by Ophaug et al., as 0.05-0.07 mg/kg. From our results, the daily fluoride intake of infants from foods in Japan is estimated to be equivalent to or lower than the values of previous reports in non-fluoridated areas. Consequently, our data support the argument that water fluoridation and the appropriate use of fluoride for dental caries prevention in Japan are needed on the basis of scientific criteria in terms of fluoride exposure related to food intake during tooth formation.