Cognitive health is subject to decline with increasing numbers of lost teeth which impacts mastication. This study is a descriptive data analysis of the association between masticatory and cognitive conditions using a large database. We obtained the dental and medical records from Japan's universal healthcare system (UHCS) from the national database in 2017. The data from 94% of the Japanese population aged 65 and over is included. It is inclusive of diagnostic codes for various types of cognitive impairment, as well as dental treatment records from 2012 to 2017. The cognitive impairment group was compared to those without a diagnosis of cognitive impairment. Crude odds ratio between loss of mastication with natural teeth (exposure) and cognitive impairments (outcome) were compared. Patients who have lost masticatory function are likely to have cognitive impairment with an odds ratio of 1.89 (p<0.0001) for early elderly (aged 65-75) and 1.33 (p<0.0001) for advanced elderly (over 75). Patients who are edentulous and function with complete dentures are likely to have cognitive impairment with an odds ratio of 2.38 (p<0.0001) and 1.38 (p<0.0001), respectively. The data shows a convincing and significant result of an association between cognitive health and oral health, related to masticatory conditions.

Japan’s universal healthcare insurance is facing economic challenges due to the advanced aging society, however, objective data of dental expenditure has never been introduced. This study aimed to identify the associated factors with dental expenditures using government-provided digitized insurance claims data and calculated the spending in the context of dental cost per person (DCPP). Seven associated factors analyzed were age, demographic, geographic, socioeconomic, regional wealth, the impact of the 8020-national campaign implementation (keep 20 teeth at age 80), and the effect of the home-visit dentistry for the elders. The average DCPP was high in older populations (75+) in all prefectures. The prefectures with the highest and lowest DCPP were significant compared to other states and retained their respective places in the cost hierarchy over the four years. The prefectures with more citizens participating in government assistance programs (GAP) had greater DCPPs. Dental costs were significantly related to geographic regions, age, per capita income, government assistance program prevalence, office complete denture frequency, and home visit care per patient. With a growing aging population, dental care costs will continue to increase, burdening its fiscal future. Associated factors identified should be considered to control the contentious increase of healthcare cost.