横井 美有希

ABSTRACT Background There is growing interest in the relationship between oral function and lifestyle‐related diseases. Objectives This study aimed to investigate the associations between the results of oral function tests and those of blood tests for lipid abnormalities, glucose metabolism and kidney function. Methods A total of 118 individuals aged ≥ 50 years (80 men and 38 women) who had undergone health check‐ups at our hospital in 2021 and 2023 were examined. Based on the fasting blood glucose (GLU), HbA1c, high‐density lipoproteins (HDL), low‐density lipoproteins (LDL), urea nitrogen (BUN) and estimated glomerular filtration rate (eGFR) values obtained from the health check‐up results; the subjects were divided into two groups: those with test values outside the reference range in 2021 and/or 2023 and those with test values within the reference range. The results of seven oral function tests were compared between the groups using the Mann–Whitney U test. p < 0.05 was considered significant. Results The group with GLU and HbA1c values outside the reference ranges had significantly lower numbers of remaining teeth (RTN) and oral diadochokinesis (OD) values compared to the group within the reference range. The groups with HDL and LDL values outside the standard ranges had a significantly higher tongue coat index (TCI) and significantly lower OD. Significant differences in TCI and OD/ta/ /ka/ were observed between BUN groups within and outside the reference range. Likewise, significant differences in TCI, RTN and OD/ta/ /ka/ were observed between eGFR groups within and outside the reference range. Conclusions Subjects with blood test values outside the reference range exhibited a decline in oral function, indicating that a decline in oral function might increase the risk of lifestyle‐related diseases and facilitate the progression of frailty.

Abstract Objective This study aims to investigate how experimental tooth loss affected learning, memory function, and brain pathophysiology in mice. Materials and Methods The mice (C57BL/6 J, 2‐month‐old, male) were divided into tooth loss and control groups. The behavioral test battery was performed at 6 and 12 months after tooth extraction. The protein levels of the tight junctions in the brains of the mice were analyzed. Hippocampal astrocyte was measured using immunohistochemical staining. Results The results of behavioral tests and biochemical analysis performed during the 6 months observation period did not show significant differences between the groups. However, the escape latency in the tooth loss group was significantly longer than that in the control group at the 12 months after tooth extraction. The level of claudin‐5 decreased in the tooth loss group. Additionally, hippocampal astrogliosis was found in the tooth loss group. Conclusions Experimental tooth loss reduced the level of claudin‐5 and caused astrogliosis in the brains of mice, which was accompanied by deterioration of learning functions. This study may provide a new insight about the association between tooth loss and cognitive dysfunction.