Fourier transform infrared spectroscopy and machine learning for Porphyromonas gingivalis detection in oral bacteria.

Porphyromonas gingivalis, a Gram-negative anaerobic bacillus, is the primary pathogen in periodontitis. Herein, we cultivated strains of oral bacteria, including P. gingivalis and the oral commensal bacteria Actinomyces viscosus and Streptococcus mutans, and recorded the infrared absorption spectra of the gases released by the cultured bacteria at a resolution of 0.5 cm-1 within the wavenumber range of 500-7500 cm-1. From these spectra, we identified the infrared wavenumbers associated with characteristic absorptions in the gases released by P. gingivalis using a decision tree-based machine learning algorithm. Finally, we compared the obtained absorbance spectra of ammonia (NH3) and carbon monoxide (CO) using the HITRAN database. We observed peaks at similar positions in the P. gingivalis gases, NH3, and CO spectra. Our results suggest that P. gingivalis releases higher amounts of NH3 and CO than A. viscosus and S. mutans. Thus, combining Fourier transform infrared spectroscopy with machine learning enabled us to extract the specific wavenumber range that differentiates P. gingivalis from a vast dataset of peak intensity ratios. Our method distinguishes the gases from P. gingivalis from those of other oral bacteria and provides an effective strategy for identifying P. gingivalis in oral bacteria. Our proposed methodology could be valuable in clinical settings as a simple, noninvasive pathogen diagnosis technique.

Association between oral health status and functional independence measure on admission in convalescent hospitalized patients.

BACKGROUND: Oral health management has become increasingly important for acute inpatients. Older patients often require extended periods of medical care, and oral health management is necessary in the convalescent period following the acute period. During the convalescent period, oral health management remains unclear as convalescent hospitals have limited dental resources, and effective dental care must be provided if the objective of hospitalization is to improve life functions. This study aimed to clarify the relationship between daily functioning and oral health status at the time of admission to a convalescent hospital to aid in improving daily functioning in the convalescent period. METHODS: We included patients admitted to the rehabilitation department of a specific convalescent hospital from January to December 2021. A total of 375 patients were included in the study, with complete data records. At admission, we gathered information from the medical records, including the patient's age, sex, primary disease, Charlson Comorbidity Index, Mini Nutritional Assessment Short-Form (MNA-SF), Functional Oral Intake Scale (FOIS), Functional Independence Measure (FIM), number of teeth, and Oral Health Assessment Tool (OHAT). Statistical analysis was conducted using SPSS Ver. 27, with a significance level of 5%. RESULTS: The mean age of the 375 participants (189 men and 186 women) was 75.0 ± 12.1 years (range, 42-97 years), and over 80% were > 65 years. About 30% of major diseases could be attributed to strokes and fractures, followed by spinal cord and spine diseases. In non-stroke patients, multiple regression analysis using FIM motor, FIM cognitive, and FIM and OHAT total scores as objective variables showed that higher total scores of MNA-SF, FOIS, and lower modified Rankin Scale and OHAT were significantly associated with better FIMs. Lower OHAT scores were significantly associated with lower FOIS and MNA-SF scores, male sex, having fewer teeth, and poor dietary patterns. CONCLUSIONS: The convalescent period is an opportune time to provide intensive dental care due to the generally stable condition and extended hospital stay. Our results suggest that oral health management, such as dysphagia rehabilitation and denture treatment, is important for maintaining and improving independence, a key objective of convalescent rehabilitation, and malnutrition improvement.

The Association between Oral Health Management and the Functional Independence Measure Scores at the Time of Admission of Inpatients to a Convalescent Hospital.

Many older patients admitted to convalescent hospitals present with impaired oral function, which is an important function of daily life. This study aimed to investigate the actual status of the oral healthcare needs of inpatients in a convalescent hospital and to clarify the relationship between the level of independence at admission and the oral function. The participants were 147 patients (94 males, 53 females, mean age: 74.6 ± 13.1 years) who received dental visits during their stay at a convalescent hospital. Information regarding general and oral health was extracted from medical records. Most patients were found to have low Functional Independence Measure motor scores, and approximately 70% had some form of oral intake, but approximately 80% had nutritional problems. The mean number of present and functional teeth were 16.6 and 20.8, respectively, and 65% of patients lost molar occlusal support. Multiple regression analysis showed significant positive correlations of high functional independence measure with age, eating status, nutritional status, and the number of functional teeth. This implied that oral health management is important for patients in a convalescent hospital and that enhancing oral health may be related to improved eating textures and better nutritional status.

Association between simple evaluation of eating and swallowing function and mortality among patients with advanced dementia in nursing homes: 1-year prospective cohort study.

BACKGROUND: A simple and predictable method of evaluating eating and swallowing has not been yet established; thus, it is difficult to implement advance care planning according to deterioration in this function. This study aimed to clarify the association between a simple evaluation of eating and swallowing function and 1-year mortality in advanced dementia patients in nursing homes in Japan. METHODS: The study included 325 residents with advanced dementia. In a baseline survey, we examined medical history, physical function, and eating and swallowing function. We recorded mortality for 1 year from baseline. Kaplan-Meier survival analysis and Cox proportional regression were performed to investigate the association between the simple evaluation of eating and swallowing function and mortality. RESULTS: Statistical analysis included data from 312 of the 325 residents who had completed the baseline survey (7 individuals with non-oral ingestion and 6 who were alive but did not reside in the nursing home 1 year later were excluded). The participants' mean age was 85.2 years, and 79.5 % of participants were female. At the 1-year follow-up, 70 patients had died. According to Cox proportional regression analysis, age, male gender, history of cerebrovascular disorder, poor results of palpation of masseter muscle tension, and modified water swallowing test were significantly associated with 1-year mortality. CONCLUSION: The results of palpation of masseter muscle tension and modified water swallowing test were associated with 1-year mortality. These routine observations can predict mortality, and may thus provide evidence of the opportunity to implement advance care planning.

Relationship between oral and gut microbiota in elderly people.

AIM: Recent studies have suggested that oral bacteria induce systemic inflammation through the alteration of gut microbiota. We examined the relationship between oral and gut microbiota to evaluate the transition of oral bacteria to the gastrointestinal tract. METHODS: Oral samples from subgingival plaque and tongue-coating and fecal samples were collected from 29 elderly subjects (age, 80.2 ± 9.1 years) and 30 adults (age, 35.9 ± 5.0 years). Genomic DNA was extracted from all samples, and DNA sequencing of bacterial 16S rRNA genes was performed for microbiota analysis. UniFrac distances were calculated to evaluate the similarity between microbial communities. RESULTS: Unweighted UniFrac distance indicated that the elderly group had a higher similarity between fecal and subgingival plaque microbiota than the adult group. Indeed, some bacterial taxa found in oral samples had a significantly higher prevalence in the feces of the elderly group than in that of the adult group. CONCLUSIONS: The prevalence of oral bacterial transition to gut may be higher in the elderly than in adults, expecting that oral health care in the elderly will affect their gut microbiota composition and consequently promote human health.

Effects of lactoferrin and lactoperoxidase-containing food on the oral microbiota of older individuals.

The oral microbiota influences health and disease states. Some gram-negative anaerobic bacteria play important roles in tissue destruction associated with periodontal disease. Lactoferrin (LF) and lactoperoxidase (LPO) are antimicrobial proteins found in saliva; however, their influence on the whole oral microbiota currently remains unknown. In this randomized, double-blinded, placebo-controlled study, the effects of long-term ingestion of LF and LPO-containing tablets on the microbiota of supragingival plaque and tongue coating were assessed. Forty-six older individuals ingested placebo or test tablets after every meal for 8 weeks. The relative abundance of bacterial species was assessed by 16S rRNA gene high-throughput sequencing. Most of the bacterial species in supragingival plaque and tongue coating that exhibited significant decreases in the test group were gram-negative bacteria, including periodontal pathogens. Decreases in the total relative abundance of gram-negative organisms in supragingival plaque and tongue coating correlated with improvements in assessed variables related to oral health, such as oral malodor and plaque accumulation. Furthermore, there was significantly less microbiota diversity in supragingival plaque at 8 weeks in the test group than in the placebo group and low microbiota diversity correlated with improvements in assessed variables related to oral health. These results suggest that LF and LPO-containing tablets promote a shift from a highly diverse and gram-negative-dominated to a gram-positive-dominated community in the microbiota of supragingival plaque and tongue coating. This microbial shift may contribute to improvements in oral health, including oral malodor and state of the gingiva.

Validity of using multi-frequency bioelectrical impedance analysis to measure skeletal muscle mass in preschool children.

[Purposes] Although it is recommended to develop a habit of physical activities, there is no easy way to measure skeletal muscle mass in preschool children, which cause the difficulty of evaluation. The purpose of this study was to examine the validity of body composition including the skeletal muscle mass assessment using multi-frequency bioelectrical impedance analysis by comparing body fat mass obtained by using multi-frequency bioelectrical impedance analysis method and body mass index formulas. [Subjects and Methods] Ninety-four children were surveyed for age, height, weight, grip strength, maximum occlusal force, thickness of muscle and fat mass (masseter and lower limb), body fat mass, skeletal muscle mass, and calf circumference. We assessed additional parameters, which were thought to be related to skeletal muscle mass, to ensure validity. [Results] A strong correlation was found in body fat mass values obtained using the multi-frequency bioelectrical impedance analysis method and those obtained using the body mass index formulas. Additionally, strong correlation coefficients were found between the skeletal muscle mass/height obtained using the multi-frequency bioelectrical impedance analysis method and grip strength and calf circumference. [Conclusion] Our results indicate that skeletal muscle mass can be reliably measured using the multi-frequency bioelectrical impedance analysis method in preschool children.

Factors affecting masticatory function of community-dwelling older people: Investigation of the differences in the relevant factors for subjective and objective assessment.

OBJECTIVE: This study aimed to examine relevant factors for subjective and objective assessment of masticatory functions and elucidate any differences between the two methods. BACKGROUND: Previous studies have reported that the results of subjective and objective assessment of masticatory function in older people do not necessarily agree. MATERIALS AND METHODS: This study included 487 community-dwelling Japanese older people (205 male and 282 female; mean age 74.1±6.3 years) who participated in a comprehensive geriatric health examination. Basic information (gender and age), higher level of competence in daily living, depression, subjective masticatory function (SMF) and objective masticatory function (OMF) assessments, cognitive function, skeletal muscle mass, handgrip strength, gait speed and oral status (number of remaining and functional teeth, mouth dryness and occlusal force) were recorded. RESULTS: Multiple logistic regression analysis showed that depression (odds ratio [OR]: 1.181, 95% confidence interval [CI]: 1.094-1.275), mouth dryness (OR: 2.037, CI: 1.212-3.423) and occlusal force (OR: 0.997, CI: 0.996-0.999) were significantly associated with SMF, whereas higher level of competence in daily living (OR: 0.730 CI: 0.586-0.910), skeletal muscle mass (OR: 0.521 CI: 0.283-0.960), number of functional teeth (OR: 0.862 CI: 0.775-0.959), number of remaining teeth (OR: 0.868 CI: 0.810-0.930) and occlusal force (OR: 0.994, CI: 0.991-0.998) were associated with OMF. CONCLUSION: Subjective masticatory functionSMF and OMF were associated with different factors, suggesting that both mental and physical factors should be taken into consideration when treating decreased masticatory function.

Effects of lactoferrin and lactoperoxidase-containing food on the oral hygiene status of older individuals: A randomized, double blinded, placebo-controlled clinical trial.

AIM: Lactoferrin and lactoperoxidase have antimicrobial effects against oral pathogens. This randomized, double-blinded, placebo-controlled parallel group study tested the efficacy of a lactoferrin and lactoperoxidase-containing tablet (LF + LPO tablet) in improving the oral hygiene status of older individuals. METHODS: A total of 46 participants (31 nursing home residents and 15 healthy older individuals) were randomly assigned to receive either lactoferrin and lactoperoxidase-containing tablets or placebo tablets, and were asked to suck on a tablet after every meal for 8 weeks. Oral and bacteriological assessments were carried out at baseline, 4 weeks and 8 weeks. RESULTS: A total of 47 participants (test group n = 20; mean age 80.4 ± 6.4 years; placebo group n = 17; mean age 85.9 ± 6.7 years) were included in the efficacy analysis. In the test group, the total number of bacteria in the tongue coating was significantly reduced at 4 and 8 weeks compared with that at baseline, and the number of Porphyromonas gingivalis and Fusobacterium nucleatum was significantly reduced at 8 weeks. The total number of bacteria and the number of P. gingivalis in the supragingival plaque were significantly reduced at 8 weeks. Furthermore, there was a significant difference in the change in the number of P. gingivalis in supragingival plaque at 8 weeks between the two groups. CONCLUSIONS: Lactoferrin and lactoperoxidase-containing tablet ingestion showed antibacterial effects on periodontal bacteria present in the tongue coating and supragingival plaque, indicating that long-term ingestion could improve the oral hygiene of older individuals. Geriatr Gerontol Int 2017; 17: 714-721.

Relationship between skeletal muscle mass and swallowing function in patients with Alzheimer's disease.

AIM: The present study verified the hypothesis that decreased skeletal muscle in older adults with Alzheimer's disease is related to Alzheimer's disease progression and decreased oral or swallowing function. METHODS: We investigated 232 patients with Alzheimer's disease (31 men, 201 women, average age 85.4 ± 5.9 years) in two regions in Japan. The patients provided basic information (sex and age), and were assessed for skeletal muscle index, dementia severity (clinical dementia rating), activities of daily living, nutritional status, oral status and swallowing function. RESULTS: Stratification by clinical dementia rating was as follows: clinical dementia rating 0.5:21 patients (9.0%), clinical dementia rating 1:85 patients (36.6%), clinical dementia rating 2:88 patients (37.9%) and clinical dementia rating 3:38 patients (16.3%). Alzheimer's disease severity was significantly related to skeletal muscle index. Logistic regression analysis showed that clinical dementia rating 3 (odds ratio 11.68, 95% confidence interval 4.52-30.20), body mass index < 18.5 (odds ratio 3.18, 95% confidence interval 1.27-8.00), calf circumference <30.5 cm (odds ratio 9.33, 95% confidence interval 2.01-43.27) and poor swallowing function (odds ratio 4.93, 95% confidence interval 1.10-22.04) had a significant effect on decreased skeletal muscle index. CONCLUSIONS: Therefore, decreased skeletal muscle mass in patients with Alzheimer's disease requires strategies to manage swallowing dysfunction. Geriatr Gerontol Int 2016; 17: 402-409.

Effects of gum chewing exercises on saliva secretion and occlusal force in community-dwelling elderly individuals: A pilot study.

AIM: Elderly individuals face the risk of reductions in saliva secretion and occlusal force caused by systemic diseases or medications that can eventually result in malnutrition and systemic complications. We tested the hypothesis that regular gum chewing exercises (GCE) would enhance saliva secretion and occlusal force in an elderly population. METHODS: A total of 12 community-dwelling elderly individuals (3 men and 9 women) participated in this study after providing informed consent. Participants carried out GCE regimens using a soft gum (GCE-S) or hard gum (GCE-H) for 2 weeks each, with a 2-week rest period between trials. Mucosal moisture on the tongue surface, resting saliva, and occlusal force were measured before and after each test gum, and changes in parameters at relevant time-points were statistically analyzed. Differences in each measurement item were assessed using the Friedman test for before and after the GCE. We used the Holm's correction for multiple comparisons if the Friedman test results were significant. The critical value for rejecting the null hypothesis was set at P < 0.05. RESULTS: Resting saliva secretion significantly increased after GCE-S, returned to baseline levels during the rest period and significantly increased again after GCE-H. Mucosal moisture and occlusal force followed a similar trend, with a significant rise after GCE-H. CONCLUSIONS: The results of the present study suggest that GCE can increase resting saliva secretion and occlusal force in elderly individuals. Further investigations are required on the appropriate use of soft and hard gums to address oral frailty in elderly individuals. Geriatr Gerontol Int 2017; 17: 48-53.

Relationship between swallowing function and the skeletal muscle mass of older adults requiring long-term care.

AIM: The present study investigated the risk factors for dysphagia among older adults who require long-term care, and also examined their systemic decrease in skeletal muscle mass. METHODS: We evaluated 399 people who required long-term care and who were residing in Omori town, Yokote city, Akita prefecture, Japan. We then analyzed data from 255 participants who had complete information available regarding their sex, age, case history (stroke, Parkinson's disease and dementia), Barthel Index, Skeletal Muscle Mass Index, oral function test and modified water swallowing test results. Participants' water swallowing test results were used to create groups with good or poor swallowing function, and a univariate analysis was carried out for each parameter. Parameters with a P-value of <0.25 in the univariate analysis were subsequently included in a multiple logistic regression model as explanatory variables, and good or poor swallowing function were defined as the dependent variables. RESULTS: After adjusting for age and sex, our analysis showed that poor tongue motility (odds ratio 17.23, 95% confidence interval 5.90-50.31, P < 0.001) and decreased Skeletal Muscle Mass Index (odds ratio 3.36, 95% confidence interval 1.41-7.99, P = 0.006) were significantly correlated with decreased swallowing function. CONCLUSIONS: Decreased swallowing function was closely correlated with poor tongue motility, and this finding is similar to those of previous studies. However, the present results also show that decreased Skeletal Muscle Mass Index is a novel risk factor for dysphagia among older adults who require long-term care.

Inactivating effects of the lactoperoxidase system on bacterial lyases involved in oral malodour production.

The main components of oral malodour have been identified as volatile sulfur compounds (VSCs), including hydrogen sulfide (H(2)S) and methyl mercaptan (CH(3)SH). The lactoperoxidase (LPO) system (consisting of LPO, glucose oxidase, glucose and thiocyanate) was previously shown to exhibit antimicrobial activities against some oral bacteria in vitro and suppressive effects on VSCs in mouth air in a clinical trial. Here, we examined the in vitro effects of the LPO system on the activities of the bacterial lyases involved in the production of VSCs by oral anaerobes. The exposure of crude bacterial extracts of Fusobacterium nucleatum and Porphyromonas gingivalis or purified methionine γ-lyase to the LPO system resulted in the inactivation of their lyase activities through l-cysteine and l-methionine, which was linked to the production of H(2)S and CH(3)SH, respectively. The exposure of living F. nucleatum and P. gingivalis cells to the LPO system resulted in the suppression of cell numbers and lyase activities. The inactivation of the crude bacterial extracts of F. nucleatum and purified methionine γ-lyase by the LPO system was partly recovered by the addition of DTT. Therefore, the LPO system may inactivate bacterial lyases including methionine γ-lyase by reacting with the free cysteine residues of lyases. These results suggested that the LPO system suppresses the production of VSCs not only through its antimicrobial effects, but also by its inactivating effects on the bacterial lyases of F. nucleatum and P. gingivalis.

Characteristics of and weaning strategies in tube-dependent children.

BACKGROUND: Despite resolution of the symptoms of eating and/or swallowing disorders, prolonged tube feeding is maintained in some children. This study summarized the characteristics of children with tube dependence and investigated the causes of tube dependence. METHODS: Clinical and growth data were evaluated using medical records and referral forms for 35 tube-dependent children. RESULTS: The children in this study had a median age of 30 months (range, 17-37 months) on the first visit and 35.5 months (range, 21.3-44.8 months) at tube removal. Seven children were not weaned from the feeding tube within the study period. Twenty-two (63%) of the children were girls, 20 (57%) were able to walk, 24 (69%) had mild mental retardation, and 33 (94%) had underlying disease. Tube-dependent children tended to weigh less than age-matched normal children. Sixteen children (45.7%) were underweight. Children who had their feeding tubes removed before age 3 were significantly younger at the initial visit than those who had their tubes removed after 3 years of age. Increased finger feeding was observed during the period before tube removal. CONCLUSION: Tube-dependent children tend to be close to normal in body growth and intellectual development. When weaning from tube feeding, interventions at earlier ages are more efficient. Reduction in or discontinuation of tube feeding and encouragement of self-feeding were effective to wean off tube feeding.

Orosensory deprivation alters taste-elicited c-Fos expression in the parabrachial nucleus of neonatal rats.

In the present study we examined the effects of neonatal orosensory deprivation on taste-elicited gustatory activity in the rat parabrachial nucleus (PBN) using the functional anatomical marker c-Fos. Animals in three groups (GG, GO and GM) received gastric cannula implantation surgery on postnatal day 9 (P9). Animals in the fourth group (MR) did not receive any surgery. GG rats were fed by infusion of artificial milk directly into the stomach. GO rats were fed by intraoral infusion of artificial milk. GM and MR rats were reared by their mother with free access to mother's milk, water and rat chow. Rats from all groups were similar in body weight and length by P21. On P21 rats in all groups were intraorally presented with 0.5M sucrose solution and the brains were extracted and processed for c-Fos immunohistochemistry. Taste-elicited c-Fos expression in both the gustatory waist area, and the external lateral subnucleus of the PBN in rats in the GG group was significantly more robust than in the other three groups. These findings suggest a substantial alteration in orosensory-evoked neuronal response in this nucleus, due to sensory or motor deprivation during a critical developmental stage.