Factors affecting the number of bacteria in saliva and oral care methods for the recovery of bacteria in contaminated saliva after brushing: a randomized controlled trial.

BACKGROUND: Oral care is important in preventing aspiration pneumonia in older adults. However, it is not clear what kind of oral care can reduce the number of bacteria in saliva. The purposes of this study are to clarify whether there is a relationship between plaque amounts and salivary bacterial counts, and how bacteria dispersed into the oral cavity by brushing can be reduced. METHODS: First, saliva samples were collected from 10 healthy adult volunteers after 30 h of unbrushing and after thorough brushing, and the total bacterial count was determined by real-time PCR. Next, 40 older adults attending an outpatient dental clinic were randomly assigned into two groups: a wiping group (20 patients) and a mouthwashing group (20 patients). Saliva was collected before and after brushing, and after wiping in the wiping group and after mouthwashing in the mouthwashing group, and the total bacterial count was quantified by real-time PCR. RESULTS: In a study of volunteers, there was no association between plaque amounts and salivary bacterial counts. In a study of older adult patients, salivary bacterial counts were significantly higher in patients with higher oral hygiene index and fewer remaining teeth. Brushing increased salivary bacterial counts. Wiping did not significantly reduce the number of bacteria, while mouthwash returned the increased number of bacteria after brushing to the pre-brushing level. CONCLUSIONS: There is no direct relationship between the amount of plaque and the number of bacteria in saliva. Brushing disperses bacteria into the oral cavity, resulting in a marked increase in the number of bacteria in saliva. Wiping does not collect the dispersed bacteria, and it seems essential to rinse the mouth after brushing. TRIAL REGISTRATION: UMIN000045854.

Relationship between Tongue Pressure and Salivary Bacteria in the Older Adults Requiring Long-Term Care.

INTRODUCTION: Aspiration pneumonia, an important issue for the older adults, is caused by an increase in pathogenic microorganisms in the saliva, aspiration, and weakened host immunity. Recently, decreased tongue pressure has been reported to be associated with dysphagia. This study aimed to investigate the relationship between decreased tongue pressure and the number of bacteria in the saliva of the older adults requiring long-term care. METHODS: This cross-sectional study involved 95 older adults requiring long-term care in a facility or at home, eating orally, and who could understand the instructions for measuring tongue pressure. Sex, age, slowness, weakness, shrinking, exhaustion, low activity, number of teeth, functional teeth unit, denture use, oral hygiene, tongue coating index, dry mouth, tongue pressure, and number of bacteria in the saliva were examined. Bacterial counts were analyzed by real-time PCR for total bacteria, total streptococci, methicillin-resistant Staphylococcus aureus, Streptococcus pneumoniae, Pseudomonas aeruginosa, Porphyromonas gingivalis, and Candida albicans. RESULTS: Multiple regression analysis showed that poor oral hygiene and decreased tongue pressure were independent risk factors for increased bacteria in the saliva. Decreased tongue pressure is significantly correlated with an increased number of total bacteria and the presence of P. gingivalis. DISCUSSION/CONCLUSION: Our results suggest that tongue pressure not only maintains the swallowing function but also prevents the increase of bacteria in the saliva of older adults requiring long-term care.

Dental needs in palliative care and problems in dental hygienist education: survey study of palliative care ward homepage, university syllabus, and academic conference abstracts.

BACKGROUND: Although end-of-life patients have a variety of oral-related symptoms, the involvement of dentists and dental hygienists in the palliative care teams is limited. This study investigates the current state of palliative care education in universities that train dentists and dental hygienists and the need for dentistry in the clinical setting of palliative medicine in Japan. METHODS: First, we investigated the involvement of dentistry in hospitals with palliative care units from a website. The number of reports on palliative care presented by dental hygienists at academic conferences around 2016, when the public medical insurance system in Japan covered oral care for patients with terminal illnesses, were examined. We also surveyed the syllabuses of the university that trained nurses, dentists, and dental hygienists to determine their education regarding palliative care. RESULTS: Of the 376 hospitals with palliative care units, 176 (46.8%) had dentistry in the hospital. Additionally, 321 hospitals (85.4%), which included those without dentistry, responded that they provided oral care by dentists and dental hygienists in the palliative care unit. There were only two presentations on palliative care in the annual meetings of the two major academic societies by dental hygienists between 2012 and 2016. However, this number increased rapidly to 47 between 2017 and 2020. The syllabus surveys showed that, compared to nursing universities, universities that trained dentists or dental hygienists had lesser education in palliative care. Furthermore, education in the universities that trained dental hygienists was mostly related to the oral care of patients with terminal illnesses, while the physical and mental conditions of end-of-life patients were not well educated. CONCLUSION: Considering that society requires the involvement of dental hygienists in the field of palliative care, it is necessary to enhance basic and clinical education of palliative care in universities that train dentists and dental hygienists to provide good oral care to patients with terminal illnesses and contribute to improving their quality of life.

Geranylgeraniol Induces PPARγ Expression and Enhances the Biological Effects of a PPARγ Agonist in Adipocyte Lineage Cells.

BACKGROUND: The global incidence of diabetes mellitus (DM) has risen precipitously, even in middle- and low-income countries. Peroxisome proliferator-activated receptor γ (PPARγ) plays an important role in the control of cellular glucose metabolism. Activation of PPARγ beneficially results in increased insulin sensitivity. However, the expression of PPARγ is reduced by obesity and several nutritional factors. Here we examined the effect of geranylgeraniol (GGOH), a bioactive compound found naturally in fruits, vegetables, and grains, on the expression and activation of PPARγ. MATERIALS AND METHODS: C3H10T1/2 mouse embryonic fibroblasts and 3T3-L1 pre-adipocytes were used as in vitro models of adipocyte differentiation and function. Quantitative reverse-transcriptase polymerase chain reaction, western blotting, Oil Red O staining, and luciferase assay were performed to respectively assess mRNA expression, protein levels, lipid droplet formation and transcriptional activity. RESULTS: GGOH increased the expression of PPARγ in adipocyte lineage cells. GGOH also enhanced adipogenesis induced by rosiglitazone, a thiazolidinedione class PPARγ agonist. CONCLUSION: GGOH induces PPARγ expression and enhances the biological effects of a PPARγ agonist in adipocyte lineage cells.

Geranylgeraniol-induced Myogenic Differentiation of C2C12 Cells.

BACKGROUND: Geranylgeraniol (GGOH) is a C20 isoprenoid found in fruits, vegetables, and grains, including rice. As a food substance, GGOH is categorized as 'Generally Recognized as Safe'. GGOH is an intermediate product in the mevalonate pathway and acts as a precursor to geranylgeranyl pyrophosphate. MATERIALS AND METHODS: C2C12 mouse myoblasts derived from muscle satellite cells were used. Quantitative reverse-transcriptase polymerase chain reaction, western blotting analysis, and immunocytochemical analysis were performed to respectively assess mRNA expression, protein levels, and the number of myofibers. RESULTS: GGOH reduced the expression levels of skeletal muscle atrophy-related ubiquitin ligases in myofibers derived from C2C12 cells. GGOH induced myogenic differentiation of C2C12 cells via geranylgeranylation. GGOH did not adversely affect the proliferation of C2C12 cells. CONCLUSION: GGOH induces myoblast differentiation in C2C12 cells.

Validity and reliability of the oral health-related caregiver burden index.

OBJECTIVE: This study developed the Oral Health-related Caregiver Burden Index (OHBI), which contains nine questions with five response options each. As a secondary objective, we aimed to clarify the relationship between oral health-related caregiver burden and general caregiver burden. BACKGROUND: There are a few reports of the oral health-related caregiver burden. METHODS: Between January 2016 and February 2016, 155 participants enrolled in the study. We conducted the survey to examine the validity and reliability of OHBI. Additionally, the cut-off score for this scale was calculated, and the relationship between OHBI and general caregiver burden (BIC-11) was examined by binomial logistic regression. RESULTS: Survey 1 was completed by 102 caregivers, of whom 58 (56.9%) were female. Survey 2 was completed by 40 caregivers, of whom 22 (55.0%) were female. Factor analysis revealed four factors in OHBI. Cronbach's α was .691-.866. OHBI scores were significantly associated with scores for each factor of the BIC-11. OHBI had a cut-off score of 10 (AUC=.881, sensitivity=.828, specificity=.744). A good-poor analysis revealed significant differences for discriminant validity. ICC, an indicator of reliability, was .449-.842. There was a significant relationship between caregiver burden and oral health-related caregiver burden according to binomial logistic regression analysis (P<.05). CONCLUSION: We developed the OHBI as a multidimensional care burden scale, which comprises nine items covering five domains. Further, we verified the relationship between general caregiver burden and oral health-related caregiver burden.

Changes in food bolus texture during mastication.

The purpose of this study was to survey the changes that occur in bolus texture from intake to swallowing during the mastication process for four types of food materials and to identify how texture is related to the number of chews. We recruited 15 young Japanese participants for this study. The subjects were asked to spit the food bolus just before swallowing when eating four different foods: cracker, boiled rice, hard gelatine gel, and soft gelatine gel. Three physical properties (hardness, adhesiveness, and cohesiveness) were measured in the bolus after being chewed for 25, 50, 75, 100, and 125% of the normal number of chews. Occlusal force and pressure as well as stimulated whole saliva volume were also measured. Extensive variation in the number of chews existed between subjects, but minimal intra-subject variation was observed. Hardness was observed to decrease, whereas cohesiveness and adhesiveness increased in a chew-dependent manner for the cracker, soft gelatine gel, and hard gelatine gel, but not boiled rice. Bolus texture appears to be largely related to the number of chews. Hardness also tended to be influenced by occlusion. The adhesiveness and hardness of the boiled rice were also greatly influenced by saliva volume and occlusal force, respectively. Hardness is an important rheological factor in food bolus texture and likely plays a significant role in determining the appropriate number of chews. Adhesiveness and cohesiveness appear to be secondary factors in this process. PRACTICAL APPLICATIONS: We propose a model of oral processing for application in determining the appropriate number of chews for an individual. Hardness appears to be an important rheological factor in food bolus texture, with adhesiveness and cohesiveness being secondary aspects. When food is hard or difficult to swallow, chewing behavior will likely be more influenced by the perception of bolus texture.

Relationship between mouthful volume and number of chews in young Japanese females.

OBJECTIVE: Modification of eating behavior in Japan is promoted to prevent overweight and obesity, but the effects of such modifications are unclear. This study aimed to clarify the inter- and intra-individual relationship between bite size and number of chews of food. DESIGN AND METHODS: Subjects comprised of 50 young healthy Japanese women (mean age 19.5 years). Food materials were boiled rice and apple. First, the average bite size and the number of chews per mouthful of food were calculated across the study cohort. The number of chews was counted by the subjects themselves and then self-reported. Correlation between the individual one-bite volume and the number of chews per volume was analyzed using Spearman's rank correlation coefficient. Second, the number of chews for three different sized bites of food (half of one bite, one bite, and one-and-a-half bites) were calculated as a prospective observational study. The number of chews for each of the three volumes of food was compared using one way ANOVA with Bonferroni correction. RESULTS: For both food types, there was a negative correlation between individual mouthful volume and number of chews for both food materials. The number of chews per volume decreased as bite sizes increased. CONCLUSION: This study demonstrated an inter- and intra-individual relationship between bite size and the number of chews and suggested that smaller bite sizes were associated with more chews per volume of food.