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BackgroundThe association between dental status and mortality in community-dwelling older adults has been documented by several studies. The aim of this study was to analyze the contribution of self-assessed chewing ability, number of remaining teeth and serum albumin levels to mortality and the interactions between the three factors.MethodsA 20-year follow-up study was conducted with 666 subjects aged 80 years (from 1996 to 2017) who resided in the 8 areas served by one health center in Iwate Prefecture. Health check-ups including physical fitness measurements were conducted at a meeting place or gymnasium. Medical interview and blood sampling were conducted by physician. Oral examination was examined by dentist. The number of remaining teeth, serum albumin levels, and self-assessed chewing ability were used as predictors of mortality.ResultsAmong the 608 subjects (233 men and 375 women) included in this study, only 12 subjects (1.97%) survived after 20 years of follow-up. For men, dental status and serum levels of albumin were significantly associated with mortality. The hazard ratios of self-assessed chewing ability calculated by item response theory analysis and the inability to chew at least one food adjusted for serum albumin and tooth conditions were statistically significant in men. When adjusted by health status evaluated by blood tests, self-assessed chewing ability was statistically significant in men. According to path analysis, self-assessed chewing ability and serum albumin independently affected mortality in men.ConclusionMasticatory dysfunction may be an important risk factor for mortality in men, even though it was self-assessed. Retaining chewing ability might be a useful predictor of longevity in older male adults.

Background/purpose Few papers were available on the interproximal cleaning efficiency by manual toothbrushes when used alone. The aim was to investigate the efficiency of commercially available toothbrushes on interproximal cleaning and determine the key properties that would make the differences. Materials and methods Artificial-teeth were coated with manicure type experimental dental plaque covering mainly the interproximal surface and fixed in the jaw model of a dental simulator. A modified scrubbing technique was employed to brush out the plaque conducted by one trained dentist using 26 different toothbrushes from the equal number of separate interproximal conditions. The rate of the plaque removal (%) was calculated by measuring the plaque free areas on the post-brush images. Results The data analysis using mixed effect modelling showed that stiffness, number of tufts and total length have effect on the rate of the plaque removable from the interproximal surfaces. Conclusion This study indicated consideration should be given to toothbrush properties to enhance plaque removal from the interproximal surfaces.

This study was designed to evaluate the cariogenic potential of Lactobacillus gasseri YIT 12321.L. gasseri YIT 12321 was isolated from the human oral cavity as a probiotic candidate strain. Three types of experimental biofilm formations on bovine enamel specimens were assessed using Streptococcus sobrinus ATCC 33478, L. gasseri YIT 12321, and a co-culture of S. sobrinus and L. gasseri YIT 12321 in vitro. L. gasseri YIT 12321 was analyzed for its ability to utilize seven carbohydrates. L. gasseri YIT 12321 was cultured in tryptic soy broth without dextrose and containing a test carbohydrate at 37 °C for 16 h.The decrease in pH in the region under the biofilm produced by L. gasseri YIT 12321 was unusually slow, and the pH was maintained above 5.5 for 16 h. The amount of biofilm and the reduction in enamel hardness were minimal in the L. gasseri YIT 12321 group among the three experimental groups. The amount of co-culture-derived biofilms was less than that of S. sobrinus biofilms. When S. sobrinus was grown using sucrose, the pH decreased to 3.98. In contrast, L. gasseri YIT 12321 cultures maintained the pH above the critical pH for dentin demineralization.L. gasseri YIT 12321 is suggested to have a low cariogenic potential. The application of this strain as a probiotic may contribute to oral safety.

Oral frailty is defined as the mild decline in oral function and located at the early and reversible stage of frailty. Therefore, early detection and early treatment of oral frailty is very useful. Simple and easy questionnaires, such as an oral frailty checklist, have been widely used for the screening and enlightenment of oral frailty of the Japanese people. We evaluate the structure and validity of the oral frailty checklist. The questionnaire of oral frailty was distributed for the citizens more than 50 years old from December 2018 to January 2019. The structural validity of the questionnaire is analyzed by structural equation modeling (SEM). The characteristics of the items are analyzed by Item Response Theory (IRT). The data of 725 subjects (360 men, 359 women, 6 no answer, mean age 71.3 &plusmn, 9.05) are analyzed. The questionnaire consisted of three latent variables. Items of &ldquo, Brushing teeth at least twice a day&rdquo, &ldquo, Regular attendance of dental clinic&rdquo, and &ldquo, Using denture&rdquo, had low discrimination ability. The questionnaire used in this study is a useful tool for the screening of oral frailty. However, its scoring system needs to be improved.

The increasing healthcare cost imposes a large economic burden for the Japanese government. Predicting the healthcare cost may be a useful tool for policy making. A database of the area-basis public health insurance of one city was analyzed to predict the medical healthcare cost by the dental healthcare cost with a machine learning strategy. The 30,340 subjects who had continued registration of the area-basis public health insurance of Ebina city during April 2017 to September 2018 were analyzed. The sum of the healthcare cost was JPY 13,548,831,930. The per capita healthcare cost was JPY 446,567. The proportion of medical healthcare cost, medication cost, and dental healthcare cost was 78%, 15%, and 7%, respectively. By the results of the neural network model, the medical healthcare cost proportionally depended on the medical healthcare cost of the previous year. The dental healthcare cost of the previous year had a reducing effect on the medical healthcare cost. However, the effect was very small. Oral health may be a risk for chronic diseases. However, when evaluated by the healthcare cost, its effect was very small during the observation period.

Although a significant association between periodontal disease and atherosclerotic cardiovascular disease has been reported, their cause-to-effect relationship remains controversial. This randomized controlled clinical trial aimed to investigate the effect of advanced self-care on atherosclerotic cardiovascular disease-related vascular function markers flow-mediated brachial artery dilatation (FMD) and serum asymmetric dimethylarginine (ADMA) level in patients with early-stage periodontal disease. The study was designed as a parallel group, 3-month follow-up, open-label, randomized controlled trial. The control group received standard care for periodontal diseases, whereas the test group additionally applied disinfectant using a custom-fabricated prescription tray for advanced self-care twice a day. Overall, 110 patients provided data for FMD and serum ADMA level. No significant improvements in FMD were observed in the control (mean increase, −0.1%; 95% confidence interval [CI], −1.0–0.8; P = 0.805) or test (mean increase, −0.3%; 95% CI, −1.1–0.4; P = 0.398) group. No significant changes in serum ADMA levels were observed (mean reduction, 0.01 μmol/L; 95% CI, −0.00–0.02; P = 0.366 and mean reduction, 0.00 μmol/L; 95% CI, −0.01–0.01; P = 0.349, respectively). No significant between-group differences were found in FMD (mean difference, −0.2%; 95% CI, −1.4–0.9; p = 0.708) or serum ADMA levels (mean difference, 0.01 nmol/L; 95% CI, −0.00–0.03; p = 0.122). Significant improvements in the average probing pocket depth were observed in the control and test groups. The bleeding on probing score in the test group was significantly reduced, while that in the control group was reduced, although not significantly. Periodontal care for a 3-month duration did not provide better endothelial function although improvements of periodontal status in patients with early-stage periodontal diseases. This trial is registered in UMIN Clinical Trials Registry (www.umin.ac.jp/ctr/; ID: UMIN000023395).

Quality of life (QOL) and mortality are true endpoints of epidemiological or medical research, especially for community-dwelling older adults. Nutritional status and activities of daily living (ADLs) are associated with QOL and mortality. Good oral health status supports a good nutritional status. The aim of this study was to elucidate the complex structure of these important health-related factors. We surveyed 354 healthy older adults at the age of 85. Nutritional status was evaluated by the serum level of albumin. QOL, ADLs, self-assessed chewing ability, serum albumin level, and mortality during the 15 year follow up period were analyzed. Self-assessed chewing ability was associated with QOL and ADLs. Self-assessed chewing ability for slight-hard foods was associated with mortality in men. However, it was not associated with the serum albumin level. The serum albumin level was associated with mortality in women. These results indicate that maintaining good oral function is not enough. Nutritional instruction in accordance with oral function is indispensable for health promotion in older adults. When planning health promotion strategies for older adults, different strategies are needed for men and women.

This study was based in a hospital setting. Patients with acute symptoms face a life-threatening crisis and often have systemic complications during the convalescence stage. During the acute stage, oral function does not work and oral hygiene status deteriorates. A gauze or sponge brush is generally used to wipe the oral cavity, however, this process does not clean the oral cavity enough. Effective oral care requires better methods. Patients participating in this study were all hospitalized by ambulance and with acute symptoms. During the convalescence stage, patients were assigned application of mucosal brushing or wiping by gauze or sponge brush by order of hospitalization. The effects were evaluated by the number of bacteria on the tongue surface, serum C-reactive protein (CRP) and body temperature. Changes in bacterial count, body temperature, and CRP were effectively reduced in the mucosal brushing group compared to the wiping by gauze or sponge brush group. Based on mixed effect modeling, the coefficient of mucosal brushing for CRP was &minus, 2.296 and for body temperature was &minus, 0.067 and statistically significant. This simple method can effectively prevent systemic complication of inpatients with deteriorated oral conditions. This method may also be effective for the elderly in nursing homes or perioperative oral-care management.

Compromised oral health can alter food choices. Poor masticatory function leads to imbalanced food intake and undesirable nutritional status. The associations among nutritional status, oral health behavior, and self-assessed oral functions status were investigated using a community-based survey. In total, 701 subjects more than 50 years old living Ebina city located southwest of the capital Tokyo were investigated. The number of remaining teeth was counted by dental hygienists. Oral health behavior and self-assessed oral functions were evaluated by oral frailty checklist. Nutritional status was evaluated by the brief-type self-administered diet history questionnaire using Dietary Reference Intakes for Japanese as reference. More than 80% of subjects&rsquo, intakes of vitamin B12, pantothenic acid, copper, and proteins were sufficient. In contrast, only 19% of subjects&rsquo, intake of vitamin A was sufficient and 35.5% for vitamin B1. More than 90% of subjects&rsquo, intakes of vitamin D and vitamin K were sufficient. Only 35.5% of subjects&rsquo, intakes of dietary fiber were sufficient. Overall, 88.9% of subjects had excess salt. The number of remaining teeth was not correlated with nutritional intakes. Oral health behavior significantly correlated with nutritional intakes. Oral functions are important for food choice, however, oral functions were not directly correlated with nutritional intakes. Comprehensive health instructions including nutrition and oral health education is necessary for health promotion.

The oral microbiome of healthy older adults has valuable information about a healthy microbiome. In this study, we collected and analyzed the oral microbiome of denture plaque and tongue coating samples from four female centenarians. After DNA extraction and purification, pyrosequencing of the V3&ndash, V4 hypervariable regions of the 16S rRNA was carried out. The bacterial taxonomy for each lead was assigned based on a search of the EzBioCloud 16S database. We obtained a total of 199,723 valid, quality-controlled reads for denture plaque and 210,750 reads for tongue coating. The reads were assigned 407 operational taxonomic units with a 97% identity cutoff. Twenty-nine species were detected in both denture plaque and tongue coatings from all subjects. Firmicutes was the most abundant phylum, the Streptococcus salivarius group was the most abundant species in both the denture plaque and tongue coatings, and the Fusobacterium nucleatum group was detected in all subjects. In the bacterial profile, species formed clusters composed of bacteria with a wide range of prevalence and abundance, not dependent on phyla, each cluster may have specific species that could be candidates for a core microbiome. Firmicutes and Veillonella were abundant phyla on both plaque and tongue coatings of centenarians.

Several studies have shown that the oral microbiome is related to systemic health, and a co-relation with several specific diseases has been suggested. The oral microbiome depends on environmental- and community-level factors. In this observational study, the oral microbiomes of children of isolated mountain people were analyzed with respect to the core oral microbiome and etiology of dental caries. We collected samples of supragingival plaque from children (age 9&ndash, 13) living in the Chin state of Myanmar. After DNA extraction and purification, next-generation sequencing of the V3&ndash, V4 hypervariable regions of the 16S rRNA was conducted. From thirteen subjects, 263,458 valid reads and 640 operational taxonomic units were generated at a 97% identity cut-off value. At the phylum level, Proteobacteria was the most abundant, followed by Firmicutes and Bacteroides. Forty-four bacteria were detected in total from all the subjects. For children without dental caries, Proteobacteria was abundant. In contrast, in children with dental caries, Firmicutes and Bacteroides were abundant. The oral microbiome of children living in an isolated area may be affected by environmental- and community-level factors. Additionally, the composition of the oral microbiome may affect the risk of dental caries.

Background In Japanese super aging society, there is a need to establish home dental care service supply system. Current situation of home dental care should be analyzed.Methods A cross-sectional survey was conducted using a self-administered postal questionnaire distributed to all members of Iwate Dental Association. Implementation of home and nursing home dental care, number of staffs of dental clinic and the contents of dental home care were analyzed. For the analysis, correspondence analysis, item response theory, and zero-inflated model were used.Results Among 354 dental clinics, 187 (52.8%) were implemented home dental care and 195 (55.1%) were implemented nursing home dental care. Dental clinics handle home dental care by part-time workers. Denture treatment and oral care was the common treatment of dental home care.Conclusion More than half of the dental clinics were not managed the home dental care. Infrastructure improvement is necessary for the sufficient supply of dental home care service.

Screening is a fundamental strategy for early detection, treatment, and prevention of progression of oral disease and those at high risk for oral disease. While numerous screening tools exist, questionnaires, and saliva tests are often suitable for screening. The questionnaire based on the PRECEDE-PROCEED model was developed, validated, and elucidated on the structural interrelationship between these two methods. In the current investigation, 311 adults had this questionnaire and saliva testing administered simultaneously during an occupational health checkup. The questionnaire was validated by classical test theory, item response theory, and path analysis. Through structural equation modeling, it was found that self-care guidance may be an important role of the family dentist. In addition, self-awareness of oral symptoms was significantly related to saliva test results. However, self-administered questionnaires and saliva tests together may provide more information than either of them alone for the detection, treatment, and prevention of progression of oral disease. Thus, simultaneous application of self-administered questionnaires and saliva tests is recommended during oral health checkups for adults.

There are no national data available of the oral health in Myanmar. In this study, we examined dental caries status of 187 school children located in the suburban area of Naypyidaw, capital of Myanmar, at the age of five and six and analyzed by the individual level and tooth level. Maxillary D and B were sensitive for dental caries almost at the same level. They were less sensitive than maxillary A. Mandibular A and B were tolerant for dental caries. Prevalence of dental caries in Myanmar children was still high. By applying item response theory and multilevel modeling, tooth level analysis can be implemented to confirm the tendency for sensitivity or tolerance for dental caries by the tooth level.

Background The association between oral health and malnutrition has been investigated in detail. The nutrition of elderly subjects in residential care homes is determined by caregivers, dietitians or nutritionists and managed by changing the consistency of their supplied food. However, few reports have described the relationship between oral condition and supplied food consistency. The objective of this study was to determine dentition status and care levels that correlate with supplied food consistency among elderly residents of care facilities. In addition, we estimated the care level at which ordinary food consistency can be supplied by caregivers who cannot diagnose dental status. Method Several factors, including dentition, wearing removable dentures, meals categorized as ordinary or processed (sliced, mashed, or liquefied), and care levels according to the Japanese standardized care-needs certification system were investigated in 276 elderly residents (male, n = 56; female, n = 220; mean age, 87.68 ± 5.94 years) of 12 fee-based care facilities. Results The results of this study showed that care levels were significantly correlated with the consistency of the food supplied to the residents. When supplied food consistency was categorized as ordinary or processed, the number of remaining teeth and the number of tooth contact pairs, either natural or artificial, were statistically significant. From logistic regression analysis, it was determined that the numbers of tooth contact pairs were statistically significant among residents requiring high levels of care. Conclusion The number of tooth contact pairs, either natural or artificial, was one of the contributing factors for deciding supplied food consistency among elderly residents of care facilities. Elderly residents requiring less than care level 3 should have ordinary meals. Electronic supplementary material The online version of this article (10.1186/s12903-019-0770-0) contains supplementary material, which is available to authorized users.

Older or heavier Rhinoceros Auklet Cerorhinca monocerata chicks are less likely to remain in their nest during pre-fledging mass recession. Older or heavier chicks have longer wings but the individual variation in wing length at fledging is small. To identify proximate triggers of fledging from a mix of candidates when chicks experienced mass recession, we selected 30 nest boxes each containing a chick and provided half of them with 30–60 g of supplementary foods in an attempt to expand their variation in growth rate. When chicks reached the minimum wing length required for fledging (130 mm), we stopped all provisioning (supplementary and parental) by closing a hatch on the nest box entrance thereby simulating mass recession and inducing fledging. With these treatments, we examined whether timing of fledging (=duration of mass recession) was only triggered by wing length to a threshold size or whether timing of fledging was delayed by younger age at peak mass or lighter peak body mass. Our result...

In developing countries, the prevalence of dental caries in children remains high, which means that implementing a simple and convenient classification is critical. The classification needs to be evidence-based and needs to reflect tooth-level information. In this study, the prevalence of dental caries in the primary dentition of 352 Myanmar school children at the ages of 5, 6, and 7 was analyzed at the tooth level to clarify the underlying data structure of the patterns of dental caries in the population. Ninety-three percent of subjects had caries in primary dentition and the mean number of decayed teeth in primary dentition was 7.54 &plusmn, 4.82. Based on the item response theory analysis, mixed-effect modeling, and Bayesian network analysis, we proposed the following classification: Group 1: No dental caries, Group 2: Dental caries in molar teeth or dental caries in maxillary anterior teeth, Group 3: Dental caries in both molar and maxillary anterior teeth, Group 4: Dental carries in mandibular anterior teeth. Dental caries (dmft) in the groups was different between groups. The results of characteristics of tooth-level information and classification presented in this study may be a useful instrument for the analysis of the data of dental caries prevalence in primary dentition.

Water-insoluble glucan (WIG) produced by mutans streptococci, an important cariogenic pathogen, plays an important role in the formation of dental biofilm and adhesion of biofilm to tooth surfaces. Glucanohydrolases, such as mutanase (α-1,3-glucanase) and dextranase (α-1,6-glucanase), are able to hydrolyze WIG. The purposes of this study were to construct bi-functional chimeric glucanase, composed of mutanase and dextranase, and to examine the effects of this chimeric glucanase on the formation and decomposition of biofilm. The mutanase gene from Paenibacillus humicus NA1123 and the dextranase gene from Streptococcus mutans ATCC 25175 were cloned and ligated into a pE-SUMOstar Amp plasmid vector. The resultant his-tagged fusion chimeric glucanase was expressed in Escherichia coli BL21 (DE3) and partially purified. The effects of chimeric glucanase on the formation and decomposition of biofilm formed on a glass surface by Streptococcus sobrinus 6715 glucosyltransferases were then examined. This biofilm was fractionated into firmly adherent, loosely adherent, and non-adherent WIG fractions. Amounts of WIG in each fraction were determined by a phenol-sulfuric acid method, and reducing sugars were quantified by the Somogyi-Nelson method. Chimeric glucanase reduced the formation of the total amount of WIG in a dose-dependent manner, and significant reductions of WIG in the adherent fraction were observed. Moreover, the chimeric glucanase was able to decompose biofilm, being 4.1 times more effective at glucan inhibition of biofilm formation than a mixture of dextranase and mutanase. These results suggest that the chimeric glucanase is useful for prevention of dental biofilm formation.

The aim of this study was to develop a method to test the anti-androgenic effects of chemicals in birds. Male Japanese quail were castrated to lead the regression of cloacal protrusion, and they were treated with testosterone or flutamide, an anti-androgenic chemical, after 3 weeks of castration. Then changes in the size of cloacal protrusion area were measured. The cloacal protrusion area increased until Day 14 in birds implanted with silastic tube containing testosterone. In testosterone-stimulated birds, the growth of cloacal protrusion was significantly suppressed by injection with a dose of 10,000μg/100g BW of flutamide. However, significant suppressive effects of flutamide were not observed with doses lower than 10,000μg/100g BW. The size of cloacal protrusion reached the maximum by Day 8 followed by decreasing from Day 13 in the birds implanted with silastic plate containing 1mg testosterone. The growth of cloacal protrusion was significantly suppressed by daily i.p. injection with 10,000μg flutamide. These results suggest that the cloacal protrusion of Japanese quail is a useful marker to test the anti-androgenic effects of chemicals in avian species.

Water-insoluble glucan (WIG) produced by mutans streptococci, an important cariogenic pathogen, plays an important role in the formation of dental biofilm and adhesion of biofilm to tooth surfaces. Glucanohydrolases, such as mutanase (α-1,3-glucanase) and dextranase (α-1,6-glucanase), are able to hydrolyze WIG. The purposes of this study were to construct bi-functional chimeric glucanase, composed of mutanase and dextranase, and to examine the effects of this chimeric glucanase on the formation and decomposition of biofilm. The mutanase gene from Paenibacillus humicus NA1123 and the dextranase gene from Streptococcus mutans ATCC 25175 were cloned and ligated into a pE-SUMOstar Amp plasmid vector. The resultant his-tagged fusion chimeric glucanase was expressed in Escherichia coli BL21 (DE3) and partially purified. The effects of chimeric glucanase on the formation and decomposition of biofilm formed on a glass surface by Streptococcus sobrinus 6715 glucosyltransferases were then examined. This biofilm was fractionated into firmly adherent, loosely adherent, and non-adherent WIG fractions. Amounts of WIG in each fraction were determined by a phenol-sulfuric acid method, and reducing sugars were quantified by the Somogyi-Nelson method. Chimeric glucanase reduced the formation of the total amount of WIG in a dose-dependent manner, and significant reductions of WIG in the adherent fraction were observed. Moreover, the chimeric glucanase was able to decompose biofilm, being 4.1 times more effective at glucan inhibition of biofilm formation than a mixture of dextranase and mutanase. These results suggest that the chimeric glucanase is useful for prevention of dental biofilm formation.