Changes in oral and cognitive functions among older Japanese dental outpatients: A 2‐year follow‐up study

Abstract

Background The relationship between oral and cognitive functions among older people is highly debated. Objective To examine whether oral functions are related to changes in the levels of mild cognitive impairment (MCI) biomarkers in older Japanese outpatients. Methods This observational study included 52 outpatients aged ≥65 years who underwent dental examinations at the Fukuoka Dental College Hospital. The Mini‐Mental State Examination (MMSE) was performed, and MCI blood biomarker levels were assessed at baseline and after 2 years. The present dental and periodontal conditions and the oral functions (tongue pressure and masticatory performance) were evaluated. Changes in parameters from baseline to follow‐up were compared using the Wilcoxon signed‐rank test, McNemar test or chi‐squared test. Associations among changes in the parameters were analysed using Spearman's rank correlation coefficient. Results The follow‐up rate in this study was 67%. The masticatory performance was improved (p < 0.001), whereas gingival inflammation was decreased (p < 0.001) over the 2‐year period. A significant increase in the MMSE score (p < 0.001) and a decrease in MCI risk (p < 0.001) were noted. The decrease in MCI risk was correlated with the increase in both masticatory performance (ρ = −0.34; p < 0.05) and MMSE score (ρ = −0.56; p < 0.01). Conclusion A decrease in MCI risk, as demonstrated by the levels of the blood biomarkers, was correlated with an increase in the masticatory performance in Japanese outpatients.

Patients with mild cognitive impairment diagnosed at dementia clinic display decreased maximum occlusal force: a cross-sectional study

“…Furthermore, the median MMSE score of MCI patients in this study was 24: lower than the cut-off MMSE score [ 41 ] for MCI diagnosis. This may be due to the participants in this study having been diagnosed with MCI based on a comprehensive evaluation using neuropsychological tests, such as the MMSE [ 24 ], in addition to neuroimaging and hematological tests and because many of them were patients who sought medical attention at a dementia clinic.…”

“…Previous research indicates that patients with MCI are more likely to have poor oral health and impairments in oral functions, such as oral diadochokinesis (ODK), which may be due to few remaining teeth and impaired tongue and lip motor function [ 21 – 23 ]. Furthermore, Mizutani et al [ 24 ] conducted a 2-year longitudinal study of older adults without dementia and reported that an increased risk of MCI, as assessed by MCI biomarkers, was associated with decreased masticatory ability. These findings suggest that oral health management by dental professionals is important for patients with MCI.…”

Changes of Oral and Physical Functions in Older Japanese Who Participated in Keyboard Harmonica and Exercise Classes during COVID-19-Related Movement Restrictions

“…A penlight and dental tweezers were used for the examination, if they could confirm the tooth condition sufficiently. Teeth with residual roots not involved in occlusion and teeth with increased mobility (Miller’s classification 3) were excluded [ 16 , 17 ].…”

Association between oral function and physical pre-frailty in community-dwelling older people: a cross-sectional study

“…Moreover, they developed a measurement protocol before the initiation of the investigation, and measurements were conducted according to the procedure of the protocol. They examined and counted the number of teeth present in each participant, and teeth with increased mobility (Miller’s classification 3) and those without a crown were excluded from the count as they were nonfunctional [ 20 , 21 ].…”

“…The participants were instructed to chew the gum freely at a rate of once per second for 60 s at a comfortable point. The color of the chewed gum was measured on a 10-point scale immediately after chewing to minimize the color change with time [ 21 ].…”