Background There is growing international interest in identifying the effects of ageing on oral health and on appropriate strategies for managing oral disorders. The Japanese Society of Gerodontology (JSG), as the official representative of researchers and clinicians interested in geriatric dentistry in Japan, makes several recommendations on the concept of "oral hypofunction." Aims This study proposes diagnostic criteria and management strategies to reduce the risk of oral hypofunction among older people. Conceptual framework We define oral hypofunction as a presentation of 7 oral signs or symptoms: oral uncleanness; oral dryness; decline in occlusal force; decline in motor function of tongue and lips; decline in tongue pressure; decline in chewing function; and decline in swallowing function. The criteria of each symptom were determined based on the data of previous studies, and oral hypofunction was diagnosed if the criteria for 3 or more signs or symptoms were met. Conclusions We recommend that more evidence should be gathered from clinical studies and trials to clarify our diagnostic criteria and management strategies.

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Oral hypofunction in the older population: Position paper of the Japanese Society of Gerodontology in 2016

Periodontitis is a multifactorial chronic inflammatory disease associated with dysbiotic plaque biofilms and characterized by progressive destruction of the tooth-supporting apparatus. Globally, it is estimated that 740 million people are affected by its severe form. Periodontitis has been suggested to be linked to obesity and metabolic syndrome. Obesity, defined as excessive fat accumulation, is a complex multifactorial chronic inflammatory disease, with a high and increasing prevalence. Metabolic syndrome is defined as a cluster of obesity, dyslipidemia, hypertension, and dysglycemia. Obesity, metabolic syndrome and periodontitis are among the most common non-communicable diseases and a large body of evidence from epidemiologic studies supports the association between these conditions. Extensive research has established plausible mechanisms to explain how these conditions can negatively impact each other, pointing to a bidirectional adverse relationship. At present there is only limited evidence available from a few intervention studies. Nevertheless, the global burden of periodontitis combined with the obesity epidemic has important clinical and public health implications for the dental team. In accordance with the common risk factor approach for tackling non-communicable diseases, it has been proposed that oral healthcare professionals have an important role in the promotion of periodontal health and general well-being through facilitation of healthy lifestyle behaviours.

/pdf/the-association-of-periodontal-diseases-with-metabolic-343cbcb7ur.pdf

The association of periodontal diseases with metabolic syndrome and obesity

The paper reviews human mastication, focusing on its age-related changes. The first part describes mastication adaptation in young healthy individuals. Adaptation to obtain a food bolus ready to be swallowed relies on variations in number of cycles, muscle strength and volume of emitted saliva. As a result, the food bolus displays granulometric and rheological properties, the values of which are maintained within the adaptive range of deglutition. The second part concerns healthy ageing. Some mastication parameters are slightly modified by age, but ageing itself does not impair mastication, as the adaptation possibilities remain operant. The third part reports on very aged subjects, who display frequent systemic or local diseases. Local and/or general diseases such as tooth loss, salivary defect, or motor impairment are then indistinguishably superimposed on the effects of very old age. The resulting impaired function increases the risk of aspiration and choking. Lastly, the consequences for eating behaviour and nutrition are evoked

Age-related changes in mastication.

https://www.jstage.jst.go.jp/article/jpr/62/4/62_432/_pdf

Factors related to masticatory performance in healthy elderly individuals

https://onlinelibrary.wiley.com/doi/pdf/10.1111/idj.12329

Oral health for an ageing population: the importance of a natural dentition in older adults

Previous studies have identified various factors related to masticatory performance. This study was aimed to investigate variations and impacts of factors related to masticatory performance among different occlusal support areas in general urban population in Japan. A total of 1875 Japanese subjects (mean age: 66·7 years) were included in the Suita study. Periodontal status was evaluated using the Community Periodontal Index (CPI). The number of functional teeth and occlusal support areas (OSA) were recorded, and the latter divided into three categories of perfect, decreased and lost OSA based on the Eichner Index. Masticatory performance was determined by means of test gummy jelly. For denture wearers, masticatory performance was measured with the dentures in place. The multiple linear regression analysis showed that, when controlling for other variables, masticatory performance was significantly associated with sex, number of functional teeth, maximum bite force and periodontal status in perfect OSA. Masticatory performance was significantly associated with number of functional teeth, maximum bite force and periodontal status in decreased OSA. In lost OSA, masticatory performance was significantly associated with maximum bite force. Maximum bite force was a factor significantly influencing masticatory performance that was common to all OSA groups. After controlling for possible confounding factors, the number of functional teeth and periodontal status were common factors in the perfect and decreased OSA groups, and only sex was significant in the perfect OSA group. These findings may help in providing dietary guidance to elderly people with tooth loss or periodontal disease.

A multifactorial model of masticatory performance: The Suita study

Background: For quantitative evaluation of masticatory ability of the elderly patients, there should be a simple and reliable method without special techniques and instruments.

Objective:  The purpose of this study was to examine the validity and reliability of a visual scoring method for assessing masticatory performance.

Materials and Methods:  A 10-stage scale for visually scoring was rated based on the range of the glucose concentration dissolved from comminuted jelly. Photographic images of comminuted jellies were produced as a standard material for each score. Fifty subjects were recruited as raters who graded the visual score for 50 photographic images of comminuted jellies on the screen of a lap-top three times in random order.

Results:  There were strong correlations (rs = 0.911– 0.981, Spearman’s rank coefficient) between the actual scores determined from the glucose concentration and the visual scores graded by subjects in all three measurements. The intraclass correlation coefficients (ICCs) of the inter-rater reliability and the ICCs of the intra-rater reliability of the visual scoring ranged from 0.946 to 0.947 and from 0.860 to 0.987 in three measurements, respectively.

Conclusions:  These results indicated that the visual scoring method was valid and reliable for evaluation of masticatory performance.

Validity and reliability of a visual scoring method for masticatory ability using test gummy jelly.

Despite the importance of masticatory performance in health promotion, assessment of masticatory performance has not been widely conducted to date because the methods are labour intensive. The purpose of this study is to investigate the accuracy of a novel system for automatically measuring masticatory performance that uses β-carotene-containing gummy jelly. To investigate the influence of rinsing time on comminuted jelly pieces expectorated from the oral cavity, divided jelly pieces were treated with two types of dye solution and then rinsed for various durations. Changes in photodiode (light receiver) voltages from light emitted through a solution of dissolved β-carotene from jelly pieces under each condition were compared with those of unstained jelly. To investigate the influence of dissolving time, changes in light receiver voltage resulting from an increase in division number were compared between three dissolving times. For all forms of divided test jelly and rinsing times, no significant differences in light receiver voltage were observed between any of the stain groups and the control group. Voltages decreased in a similar manner for all forms of divided jelly as dissolving time increased. The highest coefficient of determination (R(2)  = 0·979) between the obtained voltage and the increased surface area of each divided jelly was seen at the 10 s dissolving time. These results suggested that our fully automatic system can estimate the increased surface area of comminuted gummy jelly as a parameter of masticatory performance with high accuracy after rinsing and dissolving operations of 10 s each.

Fully automatic measuring system for assessing masticatory performance using β-carotene-containing gummy jelly

There are numerous reports on the relationship between regular utilization of dental care services and oral health, but most are based on questionnaires and subjective evaluation. Few have objectively evaluated masticatory performance and its relationship to utilization of dental care services. The purpose of this study was to identify the effect of regular utilization of dental services on masticatory performance. The subjects consisted of 1804 general residents of Suita City, Osaka Prefecture (760 men and 1044 women, mean age 66.5 ± 7.9 years). Regular utilization of dental services and oral hygiene habits (frequency of toothbrushing and use of interdental aids) was surveyed, and periodontal status, occlusal support, and masticatory performance were measured. Masticatory performance was evaluated by a chewing test using gummy jelly. The correlation between age, sex, regular dental utilization, oral hygiene habits, periodontal status or occlusal support, and masticatory performance was analyzed using Spearman's correlation test and t-test. In addition, multiple linear regression analysis was carried out to investigate the relationship of regular dental utilization with masticatory performance after controlling for other factors. Masticatory performance was significantly correlated to age when using Spearman's correlation test, and to regular dental utilization, periodontal status, or occlusal support with t-test. Multiple linear regression analysis showed that regular utilization of dental services was significantly related to masticatory performance even after adjusting for age, sex, oral hygiene habits, periodontal status, and occlusal support (standardized partial regression coefficient β = 0.055). These findings suggested that the regular utilization of dental care services is an important factor influencing masticatory performance in a Japanese urban population.

https://onlinelibrary.wiley.com/doi/pdf/10.1002/cre2.10

Does the utilization of dental services associate with masticatory performance in a Japanese urban population?: the Suita study

The masticatory efficiency in normal dentate people and complete denture wearers has been evaluated by using testing gumi-jelly. However, some complete denture wearers who cannot chew the testing gumi-jelly (20×20×10mm) within a given chewing stroke are occasionally encountered. In this study, the masticatory efficiency test using testing gumi-jelly (20×10×10mm) cut in half was examined to evaluate the masticatory function of these cases. It was indicated that there was a significant proportional correlation between the surface area of the four kinds of specimens divided into equal parts and the amount of glucose discharged from the surface of the gumi-jelly. The increasing rate of surface area after chewing the half-type was higher than the whole-type in ten complete denture wearers. In particular, the rate of increase after chewing was remarkable in patients whose masticatory efficiency was not shown by using the whole-type. It was suggested that the masticatory efficiency test using testing gumi-jelly cut in half would be an extremely useful method for patients with low masticatory function.

Sakae Yasui

Papers

A multifactorial model of masticatory performance: The Suita study

Validity and reliability of a visual scoring method for masticatory ability using test gummy jelly.

Fully automatic measuring system for assessing masticatory performance using β-carotene-containing gummy jelly

Does the utilization of dental services associate with masticatory performance in a Japanese urban population?: the Suita study

A Method of Improving the Evaluation of Masticatory Efficiency in Complete Denture Wearers by Using the Testing Gumi-jelly.