[The oral function of community-dwelling older adults complaining of an oral function deterioration: An examination using the oral function-related items of the Questionnaire for Latter-stage Elderly People].

AIM: The oral function-related items of the newly developed "Questionnaire for Latter-stage Elderly People" are based on two items of the Kihon checklist assessing the masticatory and swallowing functions. In this study, we estimated the questionnaire's application rate and investigated the oral function of the respondents. METHODS: Included were 699 older adults (274 men/425 women, average age, 73.4±6.6 years old). Those who responded positively to the related items were considered to have decreased swallowing and masticatory functions. The specific oral function was assessed based on the number of present and functional teeth; oral hygiene; oral moisture; occlusal force; oral diadochokinesis /pa/, /ta/, /ka/; tongue pressure; mixing ability; shearing ability; and Eating Assessment Tool (EAT)-10 (reference, score ≥3). RESULTS: The rates of decreased masticatory and swallowing functions were 21.5% and 26.6%, respectively, while 7.4% of participants had both. Those with a decreased masticatory function showed fewer present teeth; a lower occlusal force, oral diadochokinesis /pa/, mixing ability, shearing ability, and higher EAT-10 scores.Those with a decreased swallowing function only had higher EAT-10 scores. In the early- and latter-stage elderly, the decreased masticatory function rates were 15.6% and 29.4%, respectively, the decreased swallowing function rates were 27.8% and 25.0%, respectively, and the rates of both decreased masticatory and swallowing functions were 6.0% and 9.5%, respectively. CONCLUSION: The older adults who responded positively to the related questionnaire items, especially for items related to masticatory function, had a decreased oral function in multiple respects. The items related to the oral function in the Questionnaire for Latter-stage Elderly People are considered useful for identifying older adults with a decreased oral function.

Intra- and inter-investigator reliabilities of oral moisture measured using an oral moisture-checking device.

BACKGROUND: Oral mucosal moisture determined using oral moisture-checking devices is used as a mouth dryness evaluation method. Such devices are capable of evaluating the state of mouth dryness in a simple manner and have applicability in a wide range of subjects; however, their intra- and inter-investigator reliabilities have not yet been clarified. OBJECTIVE: This study aims to investigate the intra- and inter-investigator reliabilities of measuring oral moisture using an oral moisture-checking device for a wide range of age groups. METHODS: Intra- and inter-investigator reliabilities were investigated in 28 young subjects and 19 older subjects aged ≥65 years. Three trained investigators independently measured oral mucosal moisture values using an oral moisture-checking device. Intra-investigator reliability was assessed using the coefficient of variation (CV) and intraclass correlation coefficient (ICC) (1.1), and inter-investigator reliability was assessed using ICC (2.1). RESULTS: Mean CV was 0.015 and 0.016, mean ICC (1.1) was 0.806 and 0.877, and ICC (2.1) was 0.873 and 0.829 in the young and older subjects, respectively. CONCLUSION: In young subjects, the mean values of ICC (1.1) and ICC (2.1) of the oral moisture-checking device were 0.806 and 0.873, respectively, whereas in older subjects, these values were 0.877 and 0.829, respectively. Thus, this confirms that the examination of oral mucosal moisture using the oral moisture-checking device has sufficient intra- and inter-investigator reliabilities for a wide range of age groups.

Rate of oral frailty and oral hypofunction in rural community-dwelling older Japanese individuals.

OBJECTIVE: To clarify the rate of oral frailty and oral hypofunction in rural community-dwelling older adults in Japan. BACKGROUND: Recently, the oral function of Japanese older adults has been evaluated multilaterally based on two concepts: oral frailty and oral hypofunction. Oral frailty is defined as a decrease in the oral function accompanied by a decrease in mental and physical functions. Oral hypofunction is a disease where the oral function is comprehensively decreased. However, their rates have not yet been elucidated. MATERIALS AND METHODS: Oral frailty and oral hypofunction were evaluated in 679 older adults from rural areas. To investigate the differences in occurrence rates due to the evaluation methods, one of the subordinate symptoms of oral hypofunction, the reduced occlusal force, was evaluated based on both the occlusal force (main method) and the number of teeth (alternative method). RESULTS: The rate of oral frailty was 22.3% in men and 22.7% in women. The rate of oral hypofunction was 39.0% in men and 46.9% in women. The overall rate of oral hypofunction was 43.6% when the reduced occlusal force of oral hypofunction was evaluated using the main method and 46.4% when evaluated using the alternative method. The proportion of participants with decreased occlusal force, the number of present teeth, oral diadochokinesis, tongue pressure and masticatory performance increased with age in both men and women. CONCLUSION: Among rural community-dwelling older adults, the rate of oral frailty was 22.5% and that of oral hypofunction was 43.6%.

Validity of a visual scoring method using gummy jelly for evaluating chewing efficiency in a large-scale epidemiological survey.

BACKGROUND: Several methods exist for objectively evaluating chewing efficiency by using gummy jelly. However, the validity of the subjective visual evaluation of chewing efficiency has not been assessed. OBJECTIVE: To verify with an epidemiological study, the validity of a visual scoring method using gummy jelly by testing the relationship between masticatory performance (MP) using a fully automatic measuring system and visual score (VS) using a visual scoring method. METHODS: Community-dwelling elderly individuals (n = 1234) ≥70 years old participated. One evaluator measured VS consecutively after participants chewed the gummy jelly (ie, actual-VS). The chewed jelly was photographed. Two evaluators used the photograph to measure the gummy jelly (ie, photo-VS). To test the validity of both methods, the correlation between actual-VS and MP and between photo-VS and MP were analysed. Inter-rater reliability between the evaluators of photo-VS was analysed. RESULTS: Significant correlations existed between actual-VS and MP and between photo-VS and MP (r = 0.86-0.87; P < 0.001). The intra-class correlation coefficient of the inter-rater reliability for photo-VS was very high (0.93; P < 0.001; 95% confidence interval: 0.877-0.953); however, the distribution of photo-VS deviated slightly from the actual-VS. A large coefficient of variation in the MP for low VSs suggested the influence of incomplete comminution, which was not reflected by the VS, and the accidental swallowing of small pieces during chewing. CONCLUSION: The VS deviated slightly from the MP calculated using a fully automated method; however, the VS can be utilised for epidemiological surveys with numerous participants.

Association between sarcopenia and oral functions in community-dwelling older adults: A cross-sectional study.

BACKGROUND: Few studies have examined the state of oral function in older adults with sarcopenia. We assessed the oral functions of community-dwelling older adults with sarcopenia from multiple perspectives to clarify their potentially low oral function. METHODS: A total of 1517 (86.2%; 990 women, 527 men; mean age 76.1 ± 7.6 years) participants were included in this study. Grip strength, gait speed and skeletal muscle mass index were assessed, and sarcopenia was evaluated according to the criteria of the Asian Working Group for Sarcopenia 2019. The degree of tongue coating, oral moisture, occlusal force, tongue-lip motor function, tongue pressure, masticatory function and swallowing function were assessed. The criteria for oral hypofunction (a disease that is a combination of multiple low oral functions) were used to assess oral function. Statistical analyses were performed using Kolmogorov-Smirnov test, unpaired t-test, Mann-Whitney U test, χ2 test, and univariate and multivariable logistic regression analyses, with each oral function as the dependent variable and sarcopenia as one of the independent variables. The significance level was set at P < 0.05. RESULTS: The prevalence rates of sarcopenia and severe sarcopenia were 14.2% and 3.8%, respectively. The prevalence of oral hypofunction was 39.9%. Compared with the robust group, the sarcopenia and severe sarcopenia groups tended to have a higher frequency of the following components (all P < 0.01): low occlusal force, low tongue-lip motor function, low tongue pressure, low masticatory function, low swallowing function and oral hypofunction. Univariate logistic regression analysis showed that sarcopenia was associated with low occlusal force, low tongue-lip motor function, low tongue pressure, low masticatory function, low swallowing function and oral hypofunction. The odds ratios and 95% confidence intervals of sarcopenia for each oral function were 2.62 [2.00, 3.43], 2.21 [1.69, 2.89], 3.66 [2.79, 4.81], 3.23 [2.46, 4.25], 1.66 [1.26, 2.20] and 3.59 [2.72, 4.72], respectively. Multivariable logistic regression analysis showed that sarcopenia was associated with low occlusal force (1.63 [1.10, 2.40]), low tongue pressure (2.28 [1.65, 3.15]), low masticatory function, (1.94 [1.27, 2.97]), low swallowing function (1.64 [1.17, 2.28]) and oral hypofunction (2.17 [1.52, 3.09]). CONCLUSIONS: This study demonstrated that multiple aspects of oral function were low among community-dwelling older adults with sarcopenia. The potential decline in oral functions in older adults with sarcopenia may have been overlooked until now. This study indicates the need for dental perspectives in intervening with older adults with sarcopenia and the need to encourage them to see dental professionals.

Impact of number of functional teeth on independence of Japanese older adults.

AIM: To examine the relationship between the number of present and functional teeth at baseline and future incidence of loss of independence. METHODS: Participants were community-dwelling older individuals who participated in a comprehensive geriatric health examination conducted in Kusatsu town, Japan, between 2009 and 2015. The primary endpoint was the incidence of loss of independence among participants, defined as the first certification of long-term care insurance in Japan. The numbers of present and functional teeth at baseline were determined via an oral examination. Demographics, clinical variables (e.g., history of chronic diseases and psychosocial factors), blood nutritional markers, physical functions, and perceived masticatory function were assessed. RESULTS: This study included 1121 individuals, and 205 individuals suffered from loss of independence during the follow-up period. Kaplan-Meier estimates of loss of independence for participants with smaller numbers of present and functional teeth were significantly greater than for those with larger numbers of teeth. Cox proportional hazard analyses indicated that a smaller number of present teeth was not a significant risk factor after adjusting for demographic characteristics. However, the number of functional teeth was a significant risk factor after the adjustment (hazard ratio: 1.975 [1.168-3.340]). Additionally, higher hazard ratios were observed in other adjusted models, but they were not statistically significant. CONCLUSIONS: The number of functional teeth may be more closely related to the future incidence of loss of independence than the number of present teeth. This novel finding suggests that prosthodontic rehabilitation for tooth loss possibly prevents the future incidence of this life-event. Geriatr Gerontol Int 2022; 22: 1032-1039.

Distribution of lip-seal strength and its relation to oral motor functions.

OBJECTIVES: Lip-seal strength, which represents the muscle strength of the lips, appears to chiefly contribute to mastication and pronunciation. However, the functional characteristics of lip-seal strength in adults are still undefined. The present study aimed to understand not only the distribution of lip-seal strength in adult men and women but also the effect of age on this strength and identify oral motor functions correlated with lip-seal strength. MATERIALS AND METHODS: The subjects included 339 participants (men: 170, age 39.2 ± 18.2 years; women: 169, age 43.1 ± 19.7 years). Oral motor function was evaluated for lip-seal strength, oral diadochokinesis (ODK), tongue pressure, occlusal force, and masticatory performance. Statistical analyses included the Shapiro-Wilk, Mann-Whitney U, and Jonckheere-Terpstra tests, in addition to the Spearman's correlation analysis and curvilinear regression analysis. RESULTS: Lip-seal strength did not have a normal distribution (p < 0.001). The mean ± standard deviation and median (first quartile, third quartile) of lip-seal strength were 11.2 ± 3.4 and 10.9 (8.7, 13.2)N for the whole sample, 12.3 ± 3.4 and 11.9 (9.4, 14.4)N for men, and 10.2 ± 3.0 and 9.9 (8.0, 12.0)N for women. A significant difference was observed in lip-seal strength between men and women (p < 0.001). Oral motor functions showed a marked correlation with lip-seal strength, including tongue pressure, occlusal force, and masticatory performance and ODK (/pa/ and /ta/), tongue pressure, and masticatory ability in men and women, respectively. In women, lip-seal strength declined with increase in age. CONCLUSIONS: Lip-seal strength was non-normally distributed in both men and women, and lip-seal strength was affected by age only in women. Lip-seal strength and multiple oral motor functions were significantly correlated. Because the indicators of perioral muscle strength and performance were correlated with lip-seal strength, lip-seal strength may also partially reflect the condition of the perioral muscles.

Factors associated with masticatory performance in community-dwelling older adults: A cross-sectional study.

BACKGROUND: Decreased masticatory performance leads to deterioration of overall health among older adults. However, maintaining and improving masticatory performance in ways other than maintenance of natural teeth and appropriate prosthodontic treatment remains unclear. If the factors related to the mixing and shearing abilities for masticatory performance are clarified, it may be possible to maintain and improve the masticatory performance of older adults. We aimed to clarify the association among mixing ability, shearing ability, and masticatory performance-related factors. METHODS: Of the 707 community-dwelling older adults in Kusatsu Town, Japan, 344 who had been treated for any dental defects were enrolled in this study. Masticatory performance was evaluated on the basis of mixing ability and shearing ability. The number of natural teeth and artificial teeth, occlusal force, tongue pressure, and oral diadochokinesis /ta/ were measured as masticatory performance-related factors. Their relationship with mixing ability, shearing ability, and masticatory performance-related factors was examined by means of Spearman rank correlation coefficient and path analysis. RESULTS: Among masticatory performance-related factors, the number of natural teeth, occlusal force, and tongue pressure were directly associated with both mixing ability and shearing ability. Moreover, mixing ability was also directly associated with shearing ability. CONCLUSIONS: Tongue pressure, which can be improved by means of training, is a masticatory performance-related factor associated with both mixing and shearing abilities. PRACTICAL IMPLICATIONS: Training for tongue pressure after proper prosthetic treatment may provide an effective means of maintaining and improving masticatory performance in older adults.

Number of functional teeth more strongly predicts all-cause mortality than number of present teeth in Japanese older adults.

AIM: Previous studies on the association between intraoral conditions and mortality in community-dwelling older individuals reported that fewer present teeth (PT) are significant risk factors for mortality. However, how the number of PT relative to the number of functional teeth (FT), including both present and rehabilitated teeth, influences mortality has not been investigated fully. This study examined the impact of the number of FT on mortality among community-dwelling Japanese older adults. METHODS: This study was a retrospective, observational and population-based follow-up study, which examined 1188 older individuals who participated in an annual geriatric health examination from 2009 to 2015. The average follow-up period was 1697.0 ± 774.5 days. The primary outcome was all-cause mortality at follow-up. The numbers of PT and FT of each participant were counted during an oral examination. In addition, demographics, clinical variables, blood nutrient markers, physical functions and perceived masticatory function were measured. RESULTS: Kaplan-Meier analysis, followed by a log-rank test, revealed that fewer PT (P < 0.001) and FT (P = 0.002) were significantly associated with a reduced survival rate. Cox's proportional hazard analysis indicated that the number of FT, but not the number of PT, was a significant independent mortality risk factor after adjusting for demographics, clinical variables, nutrient markers and physical functioning (P = 0.036, hazard ratio: 2.089). CONCLUSIONS: Current results suggest that the number of FT more strongly predicts all-cause mortality than the number of PT among community-dwelling older adults. Further studies are necessary to consider the confounding of socioeconomic status and disability status. Geriatr Gerontol Int 2020; ••: ••-••.

Relationship between mild cognitive decline and oral motor functions in metropolitan community-dwelling older Japanese: The Takashimadaira study.

BACKGROUND: Diminished oral motor function is considered to be a factor influencing cognitive decline, but this association has not been clarified. The aim of the present study was to clarify the association between cognitive and oral motor function in older people with either from normal cognitive function or mild cognitive decline. METHODS: A cross-sectional study was conducted across 1118 older people (445 men, 673 women) aged ≥70 years (mean age, 77.0 ± 4.7 years) who lived in a city of Tokyo Metropolis, Japan. Cognitive function was assessed using the Mini-Mental State Examination (MMSE). Older people who had an MMSE score of 23 points or lower were excluded. To investigate the relationship between cognitive and oral motor function, Pearson's correlation, multiple linear regression, and path analysis were performed. RESULTS: Pearson's correlation revealed that, among the oral motor functions assessed, masticatory performance, occlusal force, and tongue pressure were correlated with MMSE score. Multiple linear regression showed that tongue pressure and oral diadochokinesis (ODK) were significantly associated with MMSE score. Path analysis revealed that decreases in tongue pressure and in ODK were directly associated with decreases in MMSE score. Decreases in tongue pressure were also indirectly associated with decreases in MMSE score via decreases in ODK. CONCLUSIONS: Among the oral motor functions assessed, tongue pressure and ODK were associated with cognitive function in older people ranging from those with normal cognitive function to those with mild cognitive decline. Diminished tongue pressure and ODK might thus lead to cognitive decline.