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

Factors related to subjective evaluation of difficulty in chewing among community-dwelling older adults

AIM

Awareness of difficulty chewing may limit the diversity of food intake in older adults. However, few studies have clarified which factors are related to subjective difficulty in chewing. The aim was to identify factors related to subjective difficulty in chewing in 70- and 80-year-old Japanese older adults.

METHODS

A total of 1680 participants (792 men, 888 women) were surveyed. Difficulty in chewing was assessed with questionnaires regarding food intake, such as rice, apples, beef, and hard rice crackers. The participants were classified into two groups, the "with difficulty" group (participants who answered "cannot eat," "can eat with difficulty," and "can eat if small") and the "without difficulty" group (participants who answered "can eat without problems"), according to their answers to questionnaires for each food. A logistic regression analysis with subjective difficulty in chewing as the dependent variable was performed for each food.

RESULTS

Subjective difficulty in chewing was associated with age, occlusal force, and depression for rice; age, number of remaining teeth, occlusal force, and depression for apples; number of remaining teeth, occlusal force, and depression for beef; and number of remaining teeth and occlusal force for hard rice crackers.

CONCLUSIONS

Age, number of remaining teeth, and occlusal force, as well as depression, might be related to subjective evaluation of difficulty chewing in community-dwelling Japanese older adults. Geriatr Gerontol Int 2024; 24: 327-333.

Association between oral health and locomotive syndrome: a cross-sectional study in Japanese adults

BACKGROUND

Many studies have examined the association between oral health, care needs, and physical function, but few have focused on the association between oral health and locomotive syndrome (LS). We examined the association between LS and oral-health status, such as the number of teeth and chewing function, in an adult population.

METHODS

The study included 2888 participants who underwent examinations of motor function and oral health. Individuals with LS stage 1 or higher were classified as having LS, while others were classified as not having it. Logistic regression analysis was performed using the presence or absence of LS as the dependent variable and age, sex, smoking status, drinking habit, exercise habit, walking speed, history of stroke, bone density, body mass index, metabolic syndrome, chewing function, and the number of teeth as independent variables to calculate the odds ratios (ORs) and 95% confidence intervals (CIs) for each independent variable.

RESULTS

When the number of teeth and chewing function were included separately in multivariate analyses, the OR for LS was significantly higher for participants with 0-19 teeth than for those with 28 teeth, and for participants with poor chewing function than for those with good function (adjusted ORs, 1.47 [95% CI, 1.01-2.15] and 1.73 [95% CI, 1.37-2.18], respectively). In analyses that included tooth number and chewing function as a combined independent variable, relative to individuals with 28 teeth and good masticatory function, the adjusted ORs were 2.67 (95% CI, 1.57-4.52) for those with 28 teeth and poor chewing function, 1.63 (95% CI, 1.20-2.22) for those with 20-27 teeth and poor chewing function, and 1.83 (95% CI, 1.06-3.18) for those with 0-19 teeth and poor chewing function.

CONCLUSION

Having fewer teeth and poor chewing function may be associated with LS. The maintenance of masticatory function may be important to prevent LS in adulthood.

Bolus rheology of texture adjusted food-Effect of age

Swallowing disorders, or dysphagia, affect a large part of the population due to factors such as degenerative diseases, medication side effects or simply age-related impairment of physiological oropharyngeal function. The management of dysphagia is mainly handles through texture-modified foods of progressively softer, smoother, moister textures, depending on the severity of the disorder. Rheological and physiological-related properties of boluses were determined for a group of five older persons (average age, 74) for a set of texture-modified foods: bread, cheese and tomato and the combination into a sandwich. The softest class was gel food, after which came a smooth timbale; both were compared to boluses of regular food. The subjects chewed until ready to swallow, at which point the bolus was expectorated and measured regarding saliva content, linear viscoelasticity and shear viscosity. The results were compared to those of a previously studied younger group (average age, 38). The general physiological status of the subjects was determined by hand and tongue strength, diadochokinesis and one-legged standing and showed that all subjects were as healthy and fit as the younger group. Age-related properties such as one-legged standing with closed eyes and salivary flow plus bolus saliva content were lower for the older group, but the average chews-until-swallow was surprisingly also lower. Consequently, bolus modulus and viscosity were higher than for the younger group. Overall, the intended texture modification was reflected in bolus rheological and physiological-related properties. Bolus modulus, viscosity, saliva content and chews-until-swallowed all decreased from regular food to timbale food to gel food.

Comprehensive Analyses of Masticatory Function in Maxillectomy Patients with Functioning Removable Prostheses: A Retrospective Cross-Sectional Study

The aim of this retrospective cross-sectional study was to comprehensively assess masticatory function in maxillectomy patients with functioning removable prostheses. Their general and oral profiles, the measurement values of their oral functions, including masticatory function, and the history of tumor therapy were extracted from medical charts. The correlations of masticatory function with numerical data and the effects of tumor therapy-related factors on masticatory function were evaluated. In addition, a stepwise conditional logistic regression analysis was performed to identify the potential predictive factors comprehensively. The data from 55 maxillectomy patients revealed that the median value of masticatory function (138.0 mg/dL) was higher than the threshold (100.0 mg/dL) based on the concept of oral hypofunction. Moderate correlations of masticatory function with the number of remaining teeth, the number of functioning occlusal supports, and maximum occlusal force were found, as well as a weak correlation with maximum tongue pressure. These variables also showed statistically significant coefficients (p < 0.01). No significant effect of each tumor therapy-related factor on masticatory function was detected. A logistic regression analysis identified the number of functioning occlusal supports as a significant predictive factor. These results implied the crucial interactions of masticatory function with various factors and the specificities of maxillectomy patients.

Association between masticatory performance and oral conditions in adults: A systematic review and meta-analysis

OBJECTIVES

To give an overview of the evidence on the associations between oral condition factors and masticatory performance of adults, and to evaluate the direction and level of the associations.

DATA/SOURCES

Medline (PubMed), Embase (Ovid) and CINAHL Plus (EBSCOhost) were searched up to May 2022 for cross-sectional studies on oral conditions and masticatory performance in adults. Methodological quality of the included studies was independently evaluated based on the Joanna Briggs Institute critical appraisal checklist for analytical cross-sectional studies. Data on the associations between oral condition factors and masticatory performance were extracted. Meta-analysis was conducted on correlation coefficients.

STUDY SELECTION

Of the 8,035 records identified, 97 articles (88 studies) were included in the qualitative synthesis, and 18 studies were included in the meta-analyses. Among the oral condition factors that had associations with masticatory performance, the number of natural/remaining teeth or functional tooth pairs was reported by the largest number of studies, followed by perioral muscle status, dental prosthetic status, oral moisture status and periodontal status. Results of the meta-analyses showed that the positive association with the number of natural/remaining teeth was the strongest (pooled correlation coefficient: 0.51, 95%CI: 0.48 to 0.54), followed by the number of functional tooth pairs, maximum tongue force/pressure, while the association with the oral moisture status was the weakest.

CONCLUSIONS

Number of natural/remaining teeth and functional tooth pairs, perioral muscle status, oral moisture status, dental prosthetic status and periodontal status are the main oral condition factors influencing masticatory performance. Based on the limited evidence available, among these factors, the number of natural/remaining teeth has the strongest positive association, with a very low quality of evidence.

CLINICAL SIGNIFICANCE

This study provides valuable information on the oral condition factors associated with masticatory performance, which would be important for policymakers and clinical practitioners when deciding on the strategies for improving the masticatory performance of adults. This review highlights the need for standardization of measures and classifications of masticatory performance and oral conditions.

REGISTRATION

PROSPERO (registration number: CRD42021256824).

Association of self-rated chewing function and oral health status with metabolic syndrome

PURPOSE

The study aimed to examine the association of self-rated chewing function, the number of teeth and periodontal status with metabolic syndrome.

METHODS

The participants were 11,119 adults aged 40-74 years who underwent specific health checkups, including an oral health examination, in 2018 in Japan. This study used the standard questions of the specific health checkups to obtain information on self-rated chewing function. A multinomial logistic regression analysis was performed with metabolic syndrome status as the dependent variable, and age, sex, lifestyle questions, self-rated chewing function, number of teeth, and periodontal status as the independent variables.

RESULTS

Number of teeth and periodontal status were significantly associated with metabolic syndrome after adjusting for confounding variables. Self-rated chewing function was significantly associated with metabolic syndrome in the crude analysis, but not after adjustment for confounding variables. Both number of teeth and periodontal status were significantly associated with self-rated chewing function.

CONCLUSION

There was no significant direct association between self-rated chewing function and metabolic syndrome. Self-rated chewing function may be an indicator of poor oral condition that links to metabolic syndrome.

Assessment of subjective and objective masticatory function among elderly individuals with mild cognitive impairment

BACKGROUND

Masticatory function is known to be related to cognitive ability; therefore, factors for improving masticatory function should be identified.

AIMS

This study aimed to identify factors influencing masticatory function associated with mild cognitive impairment (MCI) in elderly individuals.

METHODS

A total of 123 elderly participants [mean age: 76.5 ± 6.5 years; 82 females (66.7%), 41 males (33.3%)] were included. Cognitive function was evaluated by the Korean version of the Mini-Mental State Examination (KMMSE). Questionnaires for subjective evaluation were administered, and dynamic objective masticatory function evaluations, including chewing tests and bite force measurements, were performed. Intergroup differences were evaluated by the Wilcoxon rank-sum and chi-square test, and correlations between cognitive ability and masticatory function were evaluated by multilinear logistic regression.

RESULTS

The number of teeth, number of posterior teeth, bite force, masticatory ability index (MAI) and posterior support status showed significant differences between the normal (KMMSE > 23) and MCI (KMMSE ≤ 23) groups. However, only the MAI, representing dynamic masticatory performance, was significantly associated with MCI regardless of age, sex and removable prostheses. The number of teeth and posterior teeth, bite force, subjective masticatory ability and posterior occlusal support showed no significant association with MCI.

DISCUSSION

These results suggested the importance of chewing function for preventing the progression of cognitive impairment.

CONCLUSIONS

Considering that only the MAI was significantly associated with MCI, it is more important to improve chewing efficiency by harmonizing therapeutic prosthetics with the surrounding masticatory system than simply increasing the number of teeth to prevent or delay cognitive impairment in elderly individuals.

Associations Between Abdominal Obesity, Chewing Difficulty and Cognitive Impairment in Dementia-Free Chinese Elderly

OBJECTIVE

To investigate the independent and synergistic associations between abdominal obesity, chewing difficulty and cognitive impairment in a community-dwelling older adults sample in China.

METHODS

Cognitive function was measured by the 5 min- Montreal Cognitive Assessment (5 min-MoCA) and abdominal obesity was measured by A Body Shape Index (ABSI) in 572 participants recruited from local communities. Chewing difficulty was assessed via a self-report questionnaire. Linear regression and general logistic regression were performed to investigate the association of chewing difficulty and abdominal obesity with cognition.

RESULTS

Chewing difficulty score [β (95% CI) = -.30 (-.49, -.11)] and ABSI [β (95%CI) = -.30 (-.55, -.05)] were independently associated with worse performance on the 5 min-MoCA. Whilst ABSI was not associated with cognitive impairment, the co-existence of chewing difficulty and abdominal obesity [OR (95% CI) = 2.22 (1.18, 4.17)] was found associated with the presence of cognitive impairment.

CONCLUSION

Chewing difficulty and abdominal obesity were independently associated with cognition. Abdominal obesity and chewing may have an additive effect on cognitive function.

Association between denture use and food form in older adults requiring long-term care: A multicenter cross-sectional study

PURPOSE

This study aimed to determine whether denture use contributes to maintaining and improving food forms in long-term care facility (LTCFs) residents.

METHODS

In 888 residents of 37 LTCFs in Japan, the following were investigated: nutritional intake status, food forms, age, sex, Barthel index (BI), clinical dementia rating (CDR), number of teeth present, number of occlusal supports, swallowing function, and use of dentures. Among all residents, those who were well-nourished and had ≤9 occlusal supports were analyzed. Based on standardized criteria, the food forms consumed by the subjects were divided into two groups: dysphagia and normal diet, which were further classified into four levels. Analysis was performed using a generalized estimation equation with the four levels of food forms as dependent variables and age, sex, BI, CDR, presence of dysphagia, number of teeth present, and use of dentures as independent variables.

RESULTS

The final analysis included 622 (70.0%) residents. Of these, 380 (61.1%) used dentures. The analyses revealed that food form was significantly associated with age (adjusted odds ratio [OR], 0.98), BI (OR, 1.04), number of teeth present (OR, 1.03), presence of dysphagia (OR, 0.44), and use of dentures (OR, 2.82).

CONCLUSION

Denture use was associated with food forms among Japanese LTCF residents. This indicates that the use of dentures is related to the maintenance of food forms, even in the elderly who participate in few activities of daily living, have reduced cognitive function, and require long-term care.

Decline in Oral Function and Its Management

With the renewed focus on eating abilities in the ageing population, new concepts referred to as oral frailty and oral hypofunction have been introduced in Japan. We aimed to provide an overview of (i) the evaluation and management of oral function in ageing populations according to oral frailty and oral hypofunction and (ii) recent scientific evidence of the associations of poor oral function with physical function and nutritional status. Both oral frailty and oral hypofunction are multidimensional concepts that describe poor oral function. In epidemiologic and/or clinical settings, they are defined as the accumulation of factors leading to poor oral status. Oral hypofunction is a core component of oral frailty. To date, there are no systematic strategies for addressing oral frailty or oral hypofunction. Nevertheless, recent randomised controlled trials revealed that several components of oral function can be improved through appropriate training. On the other hand, multiple observational studies published in recent years have demonstrated that oral frailty and oral hypofunction are associated with physical function (gait performance, frailty, and sarcopenia) and nutritional status (low protein intake, poor dietary diversity, and malnutrition) in community-dwelling older adults. Moreover, studies have reported a significant association between insufficient participation in social networks and poor oral function. However, most of the studies conducted to date have utilised a cross-sectional design, which does not permit assessment of the temporal association between comprehensive oral function and general health. Maintaining good oral function may be key to longevity. However, evidence is limited thus far, and comprehensive oral function has not been studied in detail; thus, additional high-quality studies are needed.

Factors Predicting Tongue Pressure Decline among Community-Dwelling Older Adults: The Takashimadaira Study

A limited number of longitudinal studies have explored factors contributing to decreases in tongue pressure (TP). This longitudinal study aimed to clarify the factors affecting TP decline among community-dwelling older adults. We followed the Takashimadaira Study participants with a baseline TP ≥ 30 kPa for 2 years. A TP of <30 kPa at follow-up was defined as TP decline. We used Poisson regression with robust standard errors to explore the factors related to TP decline. The studied baseline variables were dental status, sociodemographic characteristics, health behaviors, appetite, medical conditions, physical function, cognitive status, and anthropometric and body composition characteristics. Inverse probability weighting (IPW) was used to adjust for selection bias. Overall, 357 individuals (159 men and 198 women) with a mean (standard deviation) age of 75.9 (4.1) years were included in the analyses. Of these, 59 study participants (16.5%) exhibited TP decline. After adjusting for baseline TP and applying IPW, poor appetite (incident rate ratio [95% confidence interval] = 1.58 [1.01−2.48]), low skeletal muscle mass index (1.66 [1.02−2.70]), and cognitive impairment (1.93 [1.12−3.33]) were associated with TP decline. In conclusion, we demonstrated that baseline appetite, body composition, and cognitive status could predict future TP decline among community-dwelling older adults.

Development a new chewing problem directory and its validation for Korean elders

Objectives

This study aimed to develop a new chewing problem directory (CPD) and validate it with oral health indicators such as total occlusion force, number of natural and rehabilitated teeth (NRT), NRT posterior, natural teeth, natural teeth posterior, and dental status among Korean elders.

Background

Chewing problem is the main oral health problem in elders. However, there has been no validated tool using both subjective and objective assessment of chewing problem.

Subjects and methods

A total of 537 participants aged 65 years or more were randomly assigned into 2 subsamples: developing sample (n = 260) for developing and internally validating the new CPD as the 1st stage and confirmation sample (n = 277) for confirming validation of CPD as the 2nd stage. CPD was developed using three subjective questionnaires (general eating, chewing nuts, and chewing meat problem) and objective NRT. Periodontitis, age, sex, education, smoking, alcohol drinking, metabolic syndrome, and frailty were considered as confounders. Following the development of CPD, CPD was validated using multiple multivariable logistic regression after controlling for confounders in confirmation sample and total sample.

Results

The Cronbach’s alpha value for three subjective questionnaires of CPD was 0.87. Among oral health indicators, NRT (0–28) showed the highest impact association with subjective chewing problem score (partial r = − 0.276). The chewing problem from the new CPD was associated with all items of oral health indicators. The prevalence of chewing problems by CPD was 57.7% in developing sample. Elders with NRT ≤ 24, compared with those with NRT ≥ 25, showed the highest impact on chewing problems by new CPD (Odds Ratio = 7.3 in the confirmation sample and 5.04 in the total sample, p < 0.05) among oral health indicators.

Conclusion

This new CPD was developed as a valid tool to evaluate the chewing problem for Korean elders in dental clinics and community-based settings.

Association between dietary hardness score and activities of daily living among individuals aged 90 years

Objectives

With the rapidly aging world population, Japan has many older people with difficulties in maintaining oral health. This study aimed to investigate the relationship between dietary hardness score and performance of activities of daily living (ADL) of 90‐year‐old individuals in rural areas of Japan.

Material and Methods

A total of 236 individuals (64 men and 172 women) aged 90 years in Mitsugi town, Hiroshima, Japan, were included. Assessment of oral status and survey of ADL were performed. The association of ADL with dietary hardness score and the number of remaining teeth was determined.

Results

The mean dietary hardness score was 8.3 ± 2.6. Eighty individuals showed independence in ADL, whereas 156 individuals showed dependence. Logistic regression analysis, adjusted for potential confounding factors, showed that dietary hardness score was associated with ADL status but not the number of remaining teeth.

Conclusion

Our findings suggest that a low dietary hardness score is associated with dependence on ADL in 90‐year‐old individuals.

Associations of general health conditions with masticatory performance and maximum bite force in older adults: A systematic review of cross-sectional studies

OBJECTIVES

To give an overview of the current evidence on the associations of general health conditions with masticatory performance and maximum bite force in older adults.

DATA/SOURCES

Three electronic databases (Medline via PubMed, Embase via Ovid and CINAHL Plus via EBSCOhost) were searched up to September 2021 for cross-sectional studies on general health conditions and masticatory performance or maximum bite force in older adults. Methodological quality of the included studies was independently evaluated based on Joanna Briggs Institute critical appraisal checklist for analytical cross-sectional studies. Data on the associations between general health conditions and masticatory performance or maximum bite force were extracted.

STUDY SELECTION

Of the 5133 records identified, 39 studies (43 articles) were included in this review. Significant negative associations were found between masticatory performance and stroke, sarcopenia, amyotrophic lateral sclerosis, chronic obstructive pulmonary disease, dyspepsia, dysphagia, anorexia, and carotid atherosclerosis. Significant negative association was found between maximum bite force and sarcopenia. There were equivocal results on the association between masticatory performance and diabetes mellitus, and between maximum bite force and stroke, and amyotrophic lateral sclerosis. There was no significant association between masticatory performance and metabolic syndrome, and between maximum bite force and progress of Parkinson's disease. Most studies revealed positive associations of physical function with masticatory performance and maximum bite force.

CONCLUSIONS

Negative associations between masticatory function of older adults and presence of several systemic diseases have been reported in a number of studies while there are positive associations between masticatory function and some physical function indicators.

CLINICAL SIGNIFICANCE

This study provides valuable information on the association of masticatory function with general health, which draws clinicians' attention to the masticatory function of older adults who suffer from certain systemic diseases or physical dysfunction, and to the need to improve their masticatory ability to achieve healthy aging.

The Relation between Masticatory Function and Nutrition in Older Individuals, Dependent on Supportive Care for Daily Living

Introduction: Associations between masticatory function and nutritional status have been suggested. Masticatory function can be divided into two subdomains, the objective capacity of an individual to mix solid food and the individual’s subjectively assessed ability to masticate solid food. Aim: The aims of this study were to assess the relationship between these subdomains and nutritional variables in older, care-dependent individuals. Materials and methods: From a group of 355 individuals with care dependency and functional limitations, individuals aged 60 and older were selected. By home visits, the subjects underwent an oral examination and answered chewing related questions. Nutritional status was assessed using the Mini Nutritional Assessment. A total of 196 individuals met the age requirement of 60 years or older. Of these, 86 subjects were able to answer the questions. Results: We could not find any concluding significant associations between the subdomains of masticatory function or the nutritional variables. Conclusions: The absence of associations could be explained by the lack of standardized and validated methods to assess masticatory function and they possibly reflect varying underlying constructs. Self-reported questionnaires seem less useful among older and care-dependent individuals, while an objective clinical measurement will be needed when evaluating masticatory function.

Relationship between skeletal bone mineral density and subjective masticatory difficulty

Background

Masticatory ability is an essential factor for sustaining quality of life and social and systemic well-being, particularly in elderly. This study aimed to reveal the association between subjective masticatory difficulty and skeletal bone mineral density (BMD).

Methods

Data from the Korean National Health and Nutrition Examination Survey, which was conducted from 2008 to 2011 were analyzed. This study included 13,092 Koreans (5656 males, 7436 females) over 50 years of age. Masticatory difficulty was evaluated based on a self-reported questionnaire. Areal BMD of the total hip, femoral neck, and lumbar spine as well as lean body mass were determined using dual-energy X-ray absorptiometry. Data about the sociodemographic characteristics, physical activity, number of teeth present, sum of decayed, missing, and filled permanent teeth (DMFT) index and Community Periodontal Index (CPI) were collected. Multivariate logistic regression analysis was conducted to analyze associations between subjective masticatory difficulty and BMD, adjusting for the confounding covariates.

Results

Significant differences were observed in the areal BMD of the total hip, femoral neck, and lumbar spine as well as lean body mass accordance with the presence of subjective masticatory difficulty in both males and females. The number of teeth, DMFT, and CPI score did not show significant differences based on the presence of self-reported satisfaction of chewing performance in both males and females. Results from multivariate logistic regression demonstrated that the subjective masticatory difficulty showed significant interactions with skeletal BMD and the associations between masticatory satisfaction and BMD of the total hip and femoral neck were more prominent in females compared to those in males.

Conclusions

The skeletal BMD, particularly areal BMD of the femoral neck was significantly associated with subjective masticatory difficulty in elderly, especially in elder females.

Interrelationships among whole-body skeletal muscle mass, masseter muscle mass, oral function, and dentition status in older Japanese adults

Background

Generalized loss of skeletal muscle mass (SMM) may modulate or otherwise affect the loss of masseter muscle mass and be responsible for low masseter muscle performance and strength (i.e., low oral function). Moreover, dentition status can affect oral function independent of the muscle state. This cross-sectional study aimed to simultaneously investigate the relationships among whole-body SMM, masseter muscle mass, oral function (masseter muscle performance and strength), and dentition status in 1349 Japanese adults (mean age = 73.6 years).

Methods

We determined the estimated masseter muscle mass (e-MMM) based on morphological measurements of the masseter muscle. Masseter muscle performance was assessed via masticatory performance evaluation scores using gum, and strength was assessed as the maximal occlusal force. Dentition status was assessed as the number of functional teeth. SMM was measured by bioelectrical impedance analysis. Structural equation modeling stratified by sex was employed to investigate associations among SMM, e-MMM, gum score, occlusal force, and number of functional teeth.

Results

The direct path from SMM to e-MMM was statistically significant, as was the direct path from e-MMM to oral function (gum score and maximum occlusal force) for both sexes. We additionally confirmed that SMM indirectly affected gum score and maximum occlusal force via e-MMM (men; standardized coefficient [95% CI] = 3.64 [1.31 to 5.96] for maximum occlusal force and 0.01 [0.01 to 0.02] for gum score, women; 2.01 [0.38 to 3.81] for maximum occlusal force and 0.01 [0.002 to 0.01] for gum score). The number of functional teeth had direct effects on e-MMM, gum score, and maximum occlusal force.

Conclusions

Low SMM was significantly indirectly associated with poor oral function through a low masseter muscle mass, and dentition status was independently associated with oral function.

Masticatory Ability for a Single Implant Mandibular Overdenture Retained by Two Different Attachments: A Randomized Controlled Trial

Objective

The aim of this randomized clinical trial was to compare the masticatory ability subjectively between ball and Cendres+Métaux Locator (CM-LOC) attachment for a single implant retained mandibular overdenture throughout a 24-month follow-up period.

Materials and Methods

Eighty completely edentulous patients were recruited. All patients received new complete dentures, and masticatory ability was recorded using a questionnaire (baseline record). All patients received a single implant in the midline of the completely edentulous mandible. After 3-month healing period, patients were randomized using sealed envelopes into two groups: ball or CM-LOC attachment. The same masticatory ability questionnaire was used to record masticatory ability for both groups after 2 weeks of pickup and 3-, 6-, 9-, 12-, and 24-month follow-up. Comparison between the study groups was done using Mann–Whitney U test for independent samples. Two-sided P values less than 0.05 were considered statistically significant.

Results

The mean masticatory scores improved for both attachments, with no statistically significant difference between them throughout the 24-month follow-up. The CM-LOC attachment group showed a greater improvement change in masticatory ability after 6- and 12-month follow-up (−12.47 ± 12.006, −11.46 ± 14.625; P=0.826), while the ball attachment group showed a slight improvement after the 24-month follow-up (−11.72 ± 12.368, −10.88 ± 11.963; P=0.778).

Conclusion

Single implant retained mandibular overdenture improved masticatory ability subjectively with no significant difference between both attachments used although the ball attachment showed better masticatory ability scores after 24-month follow-up.

Factors affecting subjective and objective masticatory function in older adults: Importance of an integrated approach

OBJECTIVES

This study aimed to subjectively and objectively assess masticatory function and identify related factors in older adults.

METHODS

From July 2017 to September 2018, we enrolled 115 healthy participants aged between 65 and 86 years. They underwent oral examination, and their stimulated salivary secretion rate and masseter muscle tone and biomechanical properties were assessed. Masticatory performance with two-colored chewing wax was objectively evaluated using the mixing ability index (MAI). Key food intake ability (KFIA) was subjectively assessed using a questionnaire.

RESULTS

The MAI score was significantly associated with the number of remaining teeth (r = 0.524, p < 0.001) and the tone (r = -0.222, p = 0.017), elasticity (r = -0.242, p = 0.009), and dynamic stiffness (r = -0.265, p = 0.004) of the masseter muscles. In contrast, the KFIA score was only significantly associated with the number of remaining teeth (r = 0.450, p < 0.001). A weak association between the MAI and KFIA scores was observed (r = 0.304, p = 0.001).

CONCLUSIONS

A combination of objective and subjective methods should be used to accurately assess masticatory function in older adults. In addition to physical factors such as the number of remaining teeth, properties of the masticatory muscles should be evaluated to improve the masticatory function of older adults.

CLINICAL SIGNIFICANCE

In addition to dental problems, various maxillofacial and oral factors must be considered when establishing management strategies for the improvement of masticatory function in older adults.

Gender differences in masticatory function in elderly adults with natural dentition

The purpose of this study was to clarify the presence or absence of gender differences in masticatory function in elderly adults with completely natural dentition. Fifty-six elderly adults aged 65 years and older (elderly group) and 60 young adults in their 20-40 s (young group) with natural dentition participated in this study. The maximum occlusal force on the habitual chewing side was measured using dental prescale. Next, the amount of glucose extraction when subjects chewed a gummy jelly on their habitual chewing side for 20 s was measured. The maximum occlusal force and masticatory performance in the elderly and young groups were compared between males and females. The relationship between the maximum occlusal force and masticatory performance was also investigated. The maximum occlusal force in the elderly and young groups was larger in males than in females, and the difference was significant. The amount of glucose extraction in the elderly and young groups was higher in males than in females, and the difference was significant. Regarding the relationship between the maximum occlusal force and the amount of glucose extraction, there was a significant positive correlation. These results suggest that there are gender differences in the masticatory function of the elderly adults with completely natural dentition, and these differences need to be noted in the evaluation of masticatory function.

Relationship between Masticatory Function and Bone Mineral Density in Community-Dwelling Elderly: A Cross-Sectional Study

The relationship between masticatory function and bone mineral density (BMD) is unclear. This cross-sectional study examined this relationship after adjusting for confounding factors. The subjects were 702 community-dwelling elderly adults (306 men, 396 women) who had been recruited for the Community-Based Healthcare Research and Education study in 2019. Objective masticatory function was assessed using the gummy jelly method. The median for each descriptive statistic was 69.0 years for age, 86.2% for the young adult mean, and 18.0 for masticatory function. Comparisons of the groups with good and poor masticatory function by sex revealed a significant difference in muscle mass and the tooth number for both sexes (p < 0.05). Men showed significant differences in age (p < 0.05) and salivary occult blood findings (p < 0.05). Multivariate analysis using propensity scores showed a significant association between masticatory function and BMD in both sexes (men: odds ratio 163.0, 95% confidence interval 1.36–19,610.55, p = 0.04; women: odds ratio 48.65, 95% confidence interval 1.52–1561.15, p = 0.03 in women). Masticatory function and BMD in the community-dwelling elderly may be related. However, other factors, including frailty and sarcopenia, may also be involved. Regular oral health care by dentists and dental hygienists may benefit this population.

Assessment of Age-Related Changes on Masticatory Function in a Population with Normal Dentition

This study aimed to investigate the influence of changes in age-related physiological muscular and dental factors on masticatory function. This study was conducted in 211 healthy participants divided into four different age groups: 20–45 years (Gr1); 45–60 years (Gr2); 61–70 years (Gr3); and ≥71 years (Gr4). For objective evaluation of masticatory function, the masticatory performance, bite force, posterior bite area (PBA), functional tooth units (FTUs), the number of remaining teeth, tongue pressure, masseter muscle thickness (MMT), and handgrip strength were examined. Food intake ability (FIA) and the Oral Health Impact Profile-14 score were assessed subjectively using questionnaires. A significant decrease in the number of remaining teeth, FTUs, handgrip strength, and FIA was found in Gr4, and a significant decrease in the tongue pressure, PBA, and bite force was found in those aged ≥61 years. In groups 1 and 3, an association of the PBA with masticatory performance was observed. However, there was no significant decreasing trend in the MMT with respect to masticatory performance with aging. With sufficient FTUs and posterior tooth support, although age-dependent decreases in the bite force, tongue pressure and handgrip strength were observed, masticatory performance was maintained. Establishing the PBA by improving occlusion through dental treatment is thought to be important for masticatory function.

Number of teeth and masticatory function are associated with sarcopenia and diabetes mellitus status among community-dwelling older adults: A Shimane CoHRE study

Objectives

We aimed to examine the number of teeth and masticatory function as oral health indices and clarify their roles in the pathogenesis of sarcopenia and diabetes mellitus in community-dwelling older adults.

Subjects and methods

This cross-sectional study was conducted with 635 older adults in Ohnan, Shimane Prefecture, in rural Japan. The number of teeth and masticatory function (measured by the number of gummy jelly pieces collected after chewing) were evaluated by dental hygienists. Sarcopenia status was assessed using handgrip strength, skeletal muscle index, calf circumference, and a possible sarcopenia diagnosis based on the Asian Working Group for Sarcopenia 2019. Diabetes mellitus status was defined as a hemoglobin A1c level ≥6.5% or self-reported diabetes. A multivariable logistic regression model was used to analyze the association between oral health, sarcopenia, and diabetes mellitus after adjusting for confounders.

Results

After adjusting for all confounders, logistic regression analysis showed that the number of remaining teeth was negatively associated with a low level of handgrip strength (odds ratio [OR], 0.961; 95% confidence interval [CI], 0.932–0.992) and possible sarcopenia (OR, 0.949; 95% CI, 0.907–0.992). Higher levels of masticatory function were also negatively associated with a low level of handgrip strength (OR, 0.965; 95% CI, 0.941–0.990) and possible sarcopenia (OR, 0.941; 95% CI, 0.904–0.979). Logistic regression analysis showed that the number of remaining teeth and a higher level of masticatory function were negatively associated with diabetes mellitus (OR, 0.978; 95% CI, 0.957–0.999; OR, 0.976; 95% CI, 0.960–0.992, respectively).

Conclusion

Our findings suggest that improvement in oral health, including the maintenance of masticatory function and remaining teeth, may contribute to the prevention of sarcopenia and diabetes mellitus in older adults.

Influential Factors of Masticatory Performance in Older Adults: A Cross-Sectional Study

While appropriate nutrient intake is important for older adults, various oral problems cause decreased masticatory function. This cross-sectional study aimed to identify the factors associated with decreased masticatory performance in older adults. Oral examinations were performed on 80 participants (mean age: 75.10 ± 5.64 years) to determine the number of functional tooth units (FTUs). Symptoms of periodontal and temporomandibular diseases were evaluated via a questionnaire. The tone, elasticity, and dynamic stiffness of the masseter muscle were measured using the Myoton^® PRO device. The mixing ability test was used to assess the masticatory performance, and the mixing ability index (MAI) was calculated. The analysis of covariance test was performed to adjust for confounding factors, and multiple logistic regression analysis was performed to identify the risk factors affecting MAI. A lower MAI was significantly associated with higher tone (p = 0.006) and lower elasticity (p = 0.013). The number of FTUs (adjusted odds ratio (OR) = 0.724, p = 0.029), tone (adjusted OR = 1.215, p = 0.016), and elasticity (adjusted OR = 4.789, p = 0.038) were independently associated with the MAI. Muscle function training and prosthetic treatments may help increase masticatory performance in older adults, which would improve overall health.

[Relationship between the rate of a decreased oral function and the nutrient intake in community-dwelling older persons: An examination using oral function-related items in a questionnaire for latter-stage elderly people]

AIM

To determine the rate of a decreased oral function using questions from the Kihon checklist corresponding to the Questionnaire for Latter-stage Elderly People and to clarify nutrient intake in older persons.

METHODS

This study targeted 511 older people (217 men, 294 women, average age 73.1±5.6 years old). Their oral function was evaluated using questions on the masticatory function and swallowing function from the Kihon checklist, corresponding to questions on the oral function in the Questionnaire for Latter-stage Elderly People. Participants who had at least one symptom measured were defined as the applicable group (AG). In addition, to evaluate the nutrient intake of the participants, interviews were conducted using the Food Frequency Questionnaire Based on Food Groups.

RESULTS

The rate of inclusion in the AG was 32.9% for the total sample, 28.2% for early-stage elderly people, and 40.1% for latter-stage elderly people. The AG rates did not differ significantly between men and women. For latter-stage elderly people, the protein-energy ratio and intakes of total energy, protein, pantothenic acid, folic acid, vitamin B6, niacin, vitamin K, copper, zinc, phosphorus, magnesium, potassium, and total dietary fiber were significantly lower in the AG than in the non-AG.

CONCLUSION

The evaluation of placement in the AG through questions on the oral function from the Kihon checklist corresponding to the Questionnaire for Latter-stage Elderly People demonstrated that the rate of a decreased oral function was higher in latter-stage elderly people than in early-stage elderly people. In addition, the latter-stage elderly people in the AG had a lower nutrient intake.

Determinants of masticatory performance assessed by mixing ability tests

STATEMENT OF PROBLEM

Studies determining the main predictors of masticatory performance by using mixing ability tests are sparse.

PURPOSE

The purpose of this clinical study was to identify potential determinants of masticatory performance assessed by analyzing a patient's masticatory ability using bicolored chewing gum and visual, quantitative, and interactive methods.

MATERIAL AND METHODS

Nondental participants attending healthcare centers were consecutively recruited in Granada, Spain. The inclusion criteria were older than18 years and resident in the coverage area of the reference healthcare centers for at least the previous 6 months. The participants were excluded if they had received dental treatment in the previous 6 months or they were unable to communicate. The masticatory performance was determined by using 2-colored chewing gum (Kiss 3 white and blue; Smint) that was masticated for a total of 20 strokes. The masticated gum was crushed between 2 transparent glass slides, creating a 1-mm-thick specimen that was subsequently scanned. The mixed-color area was calculated as a percentage by using Photoshop as described by Schimmel et al and designated as the gold standard method. In addition, all images made were analyzed by using the Web application the Chewing Performance Calculator. In addition, the masticated bolus was inspected visually, and mastication performance was classified as being poor, moderate, or good. Sociodemographic data, as well as data on behaviors, medical and nutritional status, health-related quality of life, saliva, and general oral health, were collected for all participants to identify the main determinants of masticatory performance.

RESULTS

One hundred thirty-seven participants were enrolled. The masticatory performance values obtained using both methods (gold standard method and Chewing Performance Calculator) were significantly greater for well masticated gum (P<.001), which had been visually classified as being poorly masticated (69.1% for gold standard method and 43.5% for Chewing Performance Calculator), moderately masticated (89.7% for gold standard method and 67.3% for Chewing Performance Calculator), and well masticated (97.3% for gold standard method and 80.3% for Chewing Performance Calculator). The bivariate analyses revealed that masticatory performance was significantly higher in younger people (<65 years) (P=.008), who also had a higher basal salivary flow rate (P<.001), were nondenture users (P=.002), and had more standing teeth and occlusal units (P<.001). However, the multiple regression analyses showed that the number of occlusal units was the only significant predictor of masticatory performance. In addition, the mean masticatory performance (95% confidence interval: 47.7% to 56.8%) was found to be greatly improved (by 1.2% to 2.2%), with each occlusal unit, in accordance with the Chewing Performance Calculator and between 0.8% and 1.8% according to the gold standard method; the basal masticatory performance was calculated as 72.1% to 81.2% (95% confidence interval).

CONCLUSIONS

The number of occlusal units is one of the main predictors of masticatory performance when a 2-color bolus is used to test mixing ability.

Dysphagia and masticatory performance as a mediator of the xerostomia to quality of life relation in the older population

Background

The impact of poor oral health on older adults’ quality of life is a public health problem. In this study, the mediating effects of dental status, occlusal condition, dysphagia, and masticatory performance on the association between xerostomia and oral health-related quality of life (OHRQoL) were assessed in the older adult population.

Methods

Stratified cluster sampling was used to recruit 1076 community-dwelling adults aged 65 years and older from Kaohsiung, Taiwan. Community care centers were randomly selected according to their geographic classifications (urban, rural, or mountainous areas). Assessments of dental status and occlusal condition were performed by dentists. Information on demographics, physical function, xerostomia, dysphagia and depression was collected through face-to-face interviews. Masticatory performance was evaluated using color-changeable chewing gum. OHRQoL was measured using the Geriatric Oral Health Assessment Index. Hierarchical regression models were used to assess the relationships between OHRQoL and physical function, dental status and oral function in older adults. Path analysis was used to estimate direct and indirect pathways between xerostomia and OHRQoL.

Results

Participants with xerostomia exhibited a 0.20 OHRQoL reduction (p < .001) compared with patients with no xerostomia, and the direct effect accounted for 83.3% of the total effect. Dysphagia and masticatory performance were found to exert significant mediating effects on the association between xerostomia and OHRQoL (βs = 0.20 and − 0.12, respectively; both p < .001; βs = 0.06 and − 0.09, respectively; both p < .05). Moreover, potential mediating effects of the number of functional teeth (βs = − 0.11 and − 0.43, respectively; both p < .001) and occlusal condition (βs = 0.09 and 0.13, respectively; both p < .05) on the relationship between xerostomia and masticatory performance were noted.

Conclusions

Dysphagia and masticatory performance may serve as pathways through which xerostomia affects quality of life. Early oral function intervention may be a valuable and actionable target for older adults to maintain quality of life. Our results further suggest that checkup and screening for oral dysfunction are essential to prevent or delay the onset of complications.

Masticatory ability in older individuals: A qualitative interview study

Aim

To explore older individuals’ experienced masticatory ability and the impact of masticatory ability in daily life.

Material and methods

This study applied an open‐ended exploratory approach using inductive reasoning. The design was inspired by the qualitative method grounded theory. The final sample consisted of twelve older participants. Seven were men, and five were women. The interviews were audio‐recorded and transcribed verbatim. The interviewer successively read the transcribed data and analysed the material in cooperation with the authors.

Results

Three categories developed from the data; Deteriorating oral health and functional loss, Eating habits, Prosthetic rehabilitation and function. A core category named Adaptation emerged. Adaptation describes how individuals successfully could adapt to a decreased function and in spite of this develop a positive view of their masticatory ability.

Discussion

The participants described an experience of gradually deteriorating oral function that had affected their masticatory ability. By adapting to this functional degradation, some of the participants overcame the functional deficiencies. Most participants perceived their masticatory ability to be good, even though their ability to process some food types was described as inadequate.

Conclusion

The participants had experienced deteriorating oral health and function throughout life, and they overcame this through adaptation by adjusting their eating habits. Even though prosthetic treatment might be considered successful by the participant, this does not necessarily improve dietary habits. Future research should therefore focus on how dental treatment can be combined with other interventions, such as dietary counselling and physiotherapy to recover physiological function.

Does Masticatory Ability Contribute to Nutritional Status in Older Individuals?

Mastication plays a primary role in the process of eating. Hence, compromised masticatory ability may affect the nutrition and quality of life, which are particularly important concerns among older individuals. It remains unclear how is the masticatory ability assessed regarding the nutritional status. We examined the effect of various oral factors on three masticatory ability tests conducted among older individuals. A total of 100 older individuals were enrolled in this study. Body mass index (BMI) as an indicator of nutritional status; and age, sex, and the number of occlusal and molar occlusal supports as clinical attributes were recorded. Three masticatory ability tests (masticatory efficiency, masticatory score, and satisfaction with mastication) were conducted, and tongue pressure, cheek pressure, and occlusal force were assessed as oral functions. A significant but weak correlation was found between masticatory efficiency and the masticatory score, but not between masticatory efficiency and satisfaction score. Objective masticatory efficiency was strongly associated with objective oral factors, whereas subjective assessments of masticatory ability (masticatory score and satisfaction score) were not. Furthermore, BMI was significantly associated with subjective assessments of masticatory ability but not with objective masticatory efficiency. Both subjective and objective assessments of masticatory ability, along with considerations of nutritional formulations, are required for the maintenance and improvement of nutritional status in older individuals.

Association between oral health and sarcopenia: A literature review

PURPOSE

Sarcopenia has recently been attracting attention as an early sign of the need for nursing care in older adults. Some studies have reported that oral health is related to sarcopenia and its diagnostic factors (hand grip strength, walking speed, and skeletal muscle mass). However, the relationship between oral health and sarcopenia remains poorly investigated and no review to date has compiled the available research on this relationship. The aim of this review was to summarize the current evidence describing the association between oral health and sarcopenia.

STUDY SELECTION

The internet database PubMed was searched using various combinations of related and synonymous keywords for "oral" or "dental" or "oral health" or "oral function" and "sarcopenia" or "walking speed" or "hand grip strength" or "skeletal muscle mass." A total of 27 studies found to be eligible were critically evaluated and their key findings were summarized.

RESULTS

Most of the studies were cross-sectional and conducted in Japan. A wide range of oral factors, including number of teeth, occlusal support, periodontal state, occlusal force, mastication, tongue pressure, and swallowing, were covered. The overall findings were that oral health indices could be significantly associated with sarcopenia and its diagnostic factors.

CONCLUSIONS

Relationships may exist between aspects of oral health and sarcopenia or its diagnostic factors. However, reports showing associations between oral health and sarcopenia are scarce, and definitive conclusions could not be drawn. Further longitudinal studies are necessary to confirm these relationships.

[Oral frailty is associated with food satisfaction in community-dwelling older adults]

AIM

The fact that accumulated reductions in the oral function with aging (i.e. oral frailty) lead to physical frailty has recently received considerable attention, and countermeasures are being promoted, mainly in the field of dentistry. We assessed the relationship between oral frailty and subjective food satisfaction under the hypothesis that oral frailty is also related to psychological problems.

METHODS

Participants were attendees of the fourth wave of the Kashiwa cohort study in 2016. We excluded individuals with cognitive impairment and those who had missing values in the main variables. Regarding food satisfaction, "tastiness," "enjoyment," and "amount of food" were evaluated with self-administered questionnaires. Oral conditions were evaluated based on the number of remaining teeth and oral frailty.

RESULTS

Of the 940 participants (mean age 76.3±5.1 years; 53% men), 71% responded that their food was "tasty," 96% said it was "enjoyable," 23% said that the amount of food was "large," and 63% said that the amount was "normal." While the number of teeth (20.8±8.5) was not significantly associated with food satisfaction, compared to those without oral frailty, those who had oral frailty were less likely to feel satisfaction with their meals ( "tasty," adjusted odds ratio [95% confidence interval] = 0.49 [0.29-0.83]; "large," 0.36 [0.15-0.84]; "normal," 0.44 [0.22-0.85]).

CONCLUSIONS

Our results indicated negative associations between oral frailty and food satisfaction. In addition, the absence of a significant association with the number of teeth suggests that it is necessary to maintain not only the number of teeth but also the comprehensive oral function to support older people's enriched diets.

Decreased mandibular cortical bone quality after botulinum toxin injections in masticatory muscles in female adults

This study aimed to clarify how masticatory muscle atrophy induced by botulinum toxin (BTX) injection affects cortical bone quality of the mandible using 3D modeling technology. A total of 39 young (26.9 ± 6.0 years) and 38 post-menopausal (55.3 ± 6.3 years) females were included. Computed tomography (CT) images were obtained before and after 12 months of treatment. Predictor variables were application of a stabilization splint, and/or two times of BTX injection in the bilateral temporalis and masseter muscles within a six-month interval. Outcome variables were changes in average Hounsfield units (HU) and cortical thickness of region of interest (ROI). 3D mandibular models were reconstructed using CT images, and models were used to calculate average HU and cortical thickness of ROIs, including inferior half of the lateral surface of ascending ramus, coronoid process, and temporomandibular joint condyle. Cortical bone quality at muscle insertion site was influenced by decreased muscle thickness but seemed not to be affected by decreased functional loading. Reduced functional loading seemed to influence cortical bone quality of the condyles. These effects were more remarkable in post-menopausal females. Hence, decreased masticatory muscle thickness may lead to alterations of the mandibular cortical structures, especially in post-menopausal females.

Are Self-Reported Masticatory Ability and Regular Dental Care Related to Mortality?

AIM

The aim of the study was to examine whether a combination of self-reported masticatory ability and regular dental care is linked to mortality and issuance of new long-term care insurance (LTCI) service certifications.

METHODS

Older residents in institutions or in need of LTCI certification requirements were excluded, and self-administered questionnaires were sent to 5,400 older adults in 2013; these participants were followed for 5 years. The total response rate was 94.3%, and our final sample comprised 4,824 older adults (89.3%). We used 3 items to assess self-reported masticatory ability and regular dental care. These included (1) decline in chewing abilities of the posterior teeth on either side, (2) not brushing one's own teeth or dentures at least once a day, and (3) not visiting the dentist at least once a year.

RESULTS

The mean age of the participants at baseline was 75.9 years, and 58.4% of them were women. Main outcomes included mortality (n = 562) or new LTCI certification requirements (n = 1187) during the 5-year period. Multivariate analyses revealed that a poor score on masticatory ability and on regular dental care produced significant adverse health outcomes leading to earlier negative outcomes. The score is considered poor as it increases relative to the 0-point reference.

DISCUSSION

Regular dental care (both self-and professional care) and maintaining masticatory ability are both important. Hence, public activities focusing on preventive oral health from middle age onward is important.

Three-dimensional descriptive study of the pterygomaxillary region related to pterygoid implants: A retrospective study

The objective of this study was to analyze three-dimensionally the morphological characteristics of the pterygomaxillary region related to pterygoid implants. Volume, height, width and bone density were studied in relation to age, sex and dental status. This retrospective observational study analyzed the CBCT of 52 hemi-maxillas three-dimensionally (females n = 28, males n = 24; dentate = 31, edentulous = 21). Patients were exposed between September 2009 and October 2014, and data collection was performed between November 2015 and May 2016. Bone density, volume, height and width were analyzed in various locations of the maxilla and pterygoid process, and the variables age, gender and dental status patients were compared. The results show that the mean width of the pterygomaxillary joint was 7.5 mm (SD 1.00 mm), mean height was 12.51 mm (SD 1,82 mm) and mean volume was 321.7 mm³ (SD 142.02 mm³). Statistically significant differences between dentate and edentulous patients were found, showing a higher osseous density in dentate patients in the pterygoid process (758.2, SD 106.8, 95% CI 729.2 to 787.3 GSD - Gray Scale Density - compared to 689.9, SD 107.3, 95% CI 660.8 to 719.1 GSD; P = 0.022). In the maxilla, density was statistically significant lower in female subjects (571.0, SD 74.1, 95% CI 594.9 to 645.4 GSD) than in male subjects (620.2, SD 93.8, 95% CI 594.4 to 645.4 GSD, P = 0.047). In conclusion, due to the significant variation in the morphological characteristics of the pterygomaxillary region among subjects, personalized pre-surgical radiological assessment should always be performed. Gender, age and dental status are critical factors as they significantly affect bone density in this region.

The association between bilateral maximum occlusal force and all-cause mortality among community-dwelling older adults: The Tsurugaya project

PURPOSE

This study aimed to investigate the relationship between the bilateral maximum occlusal force (MOF) of full dental arches and all-cause mortality in a group of community-dwelling older males and females in Japan.

METHODS

This 13-year prospective cohort study was conducted among 815 older adults (395 male and 420 female) aged 70 years or over (mean age ± standard deviation: 75.1 ± 4.5 years). Bilateral MOF in the intercuspal position was recorded with horseshoe-shaped pressure-sensitive film. Participants were grouped by gender into tertiles according to MOF. Demographic variables, chronicity, comorbidity, physical status, cognitive and psychological status, social functioning, and blood chemistry data were also assessed. Information regarding all-cause mortality and migration was obtained from the Sendai Municipal Authority. Cox proportional hazard modeling was performed to assess all-cause mortality during the follow-up period.

RESULTS

In total, 159 male and 109 female participants died over a median 12.9-year follow-up period, and the cumulative mortality significantly increased with lower MOF in both males and females. The multivariate Cox proportional hazard model demonstrated a significant increase in the risk of all-cause mortality associated with lower tertiles of MOF, relative to the upper tertile in males (hazard ratio: 1.62; 95% confidence interval: 1.05-2.51) and females (hazard ratio: 1.94; 95% confidence interval: 1.10-3.56).

CONCLUSIONS

There was a significant and independent association of bilateral MOF with all-cause mortality in community-dwelling elderly males and females in Japan. These findings suggested that maintenance of oral functioning contributes to general health.

Relationships of maxillofacial morphology and malocclusion with handgrip strength in adult women

OBJECTIVES

Maxillofacial morphology and malocclusion are related to maximum occlusal force (MOF). Although it has been reported that MOF was related to handgrip strength (HS), the relationships between maxillofacial morphology/malocclusion and HS remain unclear. This study aimed to examine the relationships between maxillofacial morphology, malocclusion and HS.

SETTING AND SAMPLE POPULATION

Eighty-five women with malocclusion, aged 18-40 years, were selected.

MATERIALS AND METHODS

Lateral cephalometric radiographs (SNA, SNB, ANB, mandibular plane-FH, and gonial angles, overjet and overbite), the Peer Assessment Rating (PAR) index and HS were measured. Subjects were classified by the Japanese normal mean value of cephalometric analysis or the reference value which was defined by degree of malocclusion in each PAR index measurement item (small/low: value < mean/reference value, large/high: value ≧ mean/reference value). Measurements were then compared between groups.

RESULTS

HS of the large-gonial angle group was lower than that of the small-gonial angle group. In the small-overbite group or high-transverse (PAR index score showing crossbite/scissor bite in the canine and molars) group, HS in the large-gonial angle group was significantly lower than that in the small-gonial angle group.

CONCLUSIONS

Our results suggest that gonial angle is the largest factor affecting HS. HS may be especially low in those subjects with a large gonial angle and a small overbite or a crossbite/scissor bite in the molar section.

Socioeconomic status, oral health and dental disease in Australia, Canada, New Zealand and the United States

BACKGROUND

Socioeconomic inequalities are associated with oral health status, either subjectively (self-rated oral health) or objectively (clinically-diagnosed dental diseases). The aim of this study is to compare the magnitude of socioeconomic inequality in oral health and dental disease among adults in Australia, Canada, New Zealand and the United States (US).

METHODS

Nationally-representative survey examination data were used to calculate adjusted absolute differences (AD) in prevalence of untreated decay and fair/poor self-rated oral health (SROH) in income and education. We pooled age- and gender-adjusted inequality estimates using random effects meta-analysis.

RESULTS

New Zealand demonstrated the highest adjusted estimate for untreated decay; the US showed the highest adjusted prevalence of fair/poor SROH. The meta-analysis showed little heterogeneity across countries for the prevalence of decayed teeth; the pooled ADs were 19.7 (95% CI = 16.7-22.7) and 12.0 (95% CI = 8.4-15.7) between highest and lowest education and income groups, respectively. There was heterogeneity in the mean number of decayed teeth and in fair/poor SROH. New Zealand had the widest inequality in decay (education AD = 0.8; 95% CI = 0.4-1.2; income AD = 1.0; 95% CI = 0.5-1.5) and the US the widest inequality in fair/poor SROH (education AD = 40.4; 95% CI = 35.2-45.5; income AD = 20.5; 95% CI = 13.0-27.9).

CONCLUSIONS

The differences in estimates, and variation in the magnitude of inequality, suggest the need for further examining socio-cultural and contextual determinants of oral health and dental disease in both the included and other countries.

Factors related to dissociation between objective and subjective masticatory function in Japanese community-dwelling elderly adults

Clinicians' evaluations of older adults sometimes reveal inconsistencies between objective and subjective dental status. This study investigated which factors contribute both to good objective masticatory function (OMF) and the poor subjective masticatory function (SMF) that often becomes a clinical issue. Study participants included 635 elderly community-dwelling Japanese adults who underwent a comprehensive geriatric health examination in 2012. SMF was assessed with a question from the Kihon Checklist on eating difficulties (poor or good). OMF was assessed by a colour-changing gum (poor or good). Also investigated were age, sex, depressive symptoms, instrumental activities of daily living (I-ADLs), number of people who joined the participant at dinner, grip strength, usual walking speed, number of remaining teeth, number of functional teeth and their occlusal force. The group with good OMF and good SMF, defined as group 1, and the group with good OMF but poor SMF, group 2, were compared. Logistic regression analyses confirmed that the number of remaining and functional teeth participants had was statistically unrelated to differences between OMF and SMF. Instead, differences were related to stronger depressive symptoms (OR = 1.67, CI = 1.14-2.44), less ability to conduct I-ADL activities (OR = 0.73, CI = 0.59-0.91), slower usual walking speeds (OR = 0.18, CI = 0.06-0.58) and less occlusal force (OR = 0.99, CI = 0.99-1.00). Depressive symptoms, I-ADLs, and physical function are shown to be significantly related to divergence between objective and subjective masticatory function in elderly Japanese. This suggests that dissociations between objective and subjective dental evaluations of elderly adults indicate need for assessment of their mental and physical function.