Tooth Loss-associated Cognitive Impairment in the Elderly: A Community-based Study in Japan

Abstract

Objective Dementia is a major cause of disruption for a healthy life expectancy in Japan. It has been suggested that the number of teeth is a modifiable risk factor for cognitive impairment and dementia. We therefore examined the possible association between the cognitive function and the number of natural and artificial teeth in community-dwelling Japanese elderly individuals. Methods Among the participants in our prospective, community-based study, 210 elderly individuals (103 men and 107 women; 78.1±4.9 years; mean age±standard deviation) underwent both dental examinations and a Mini-Mental State Examination (MMSE), as well as various medical checkups, in 2016 and 2017. Results The number of natural teeth was significantly associated with an individual's MMSE score. The percentage of cognitively normal subjects (MMSE scores: 27-30) decreased significantly with a decrease in the number of natural teeth. Among the MMSE items, the calculation ability was significantly and independently associated with the number of natural teeth. Regression was calculated as the predicted score of MMSE =21+0.3×(years of schooling)+0.1×(number of natural teeth). Among individuals with 19 or fewer natural teeth, those who had a total of 20 teeth or more, including both natural and artificial teeth, had significantly higher MMSE scores than those who had 19 or fewer natural and artificial teeth combined. Conclusion The number of natural teeth was significantly associated with the cognitive function, especially the calculation ability, and the use of artificial teeth was associated with the preservation of the cognitive function in community-dwelling elderly individuals.

Neurodegeneration of Trigeminal Mesencephalic Neurons by the Tooth Loss Triggers the Progression of Alzheimer’s Disease in 3×Tg-AD Model Mice

“…Clinically, many cohort studies have demonstrated that poor oral health leading to tooth loss and periodontal diseases are major risk factors for the progression of cognitive impairment [8,9], and recently several studies indicated the association between tooth loss and cognitive function [10][11][12][13][14][15]. It has been suggested that tooth loss has effects on the progressive development of dementia due to chronic inflammation caused by periodontitis [15,16], the invasion of oral pathogens and their toxins into the brain [17], reduced masticatory forces [18,19], and neurodegeneration in the hippocampus [20].…”

The relation of poor mastication with cognition and dementia risk: a population-based longitudinal study

“…Several studies have shown that tooth loss is associated with steeper global cognitive decline [4,5], an increased risk for cognitive impairment [6][7][8] and dementia [9], as well as brain atrophy in cognitively normal older individuals [10]. One cross-sectional study found that jaw mobility, bite strength and complaints about AGING masticatory function were associated with variation in episodic memory and executive function [11].…”

Predictors of having a dentist among older adults in Iowa

“…Tooth loss can also impact facial appearance and therefore affect self‐esteem and socialization . Other systemic conditions, such as cognitive decline and peripheral arterial disease, as well as overall mortality, have been linked to tooth loss. Financial limitations have also been linked to reduced oral healthcare utilization among older adults in multiple countries, and increased oral health insurance coverage is associated with higher use of oral healthcare services …”