Association between occlusal support, salivary amyloid-β42 levels, and cognitive function in older adults: A cross-sectional pilot study

Background: Recent studies have highlighted a possible oral-systemic connection between decreased oral function, particularly reduced occlusal support, and cognitive decline. However, studies examining the relationship between occlusal support and peripheral biomarkers such as salivary amyloid-β42 (Aβ 42 ) remain limited. Objective: This study examined the association between occlusal support and cognitive decline by analyzing salivary Aβ 42 levels in older adults. Methods: A cross-sectional study was conducted among 62 participants categorized by occlusal support using the Eichner Index. Meanwhile, cognitive function and daily living abilities were assessed using the Mini-Mental State Examination (MMSE) and Lawton Instrumental Activities of Daily Living Scale (IADL). Salivary Aβ 42 levels were quantified using enzyme linked immunosorbent type assays. Results: Participants with reduced occlusal support exhibited lower MMSE and IADL scores, and higher salivary Aβ 42 levels (p < 0.05). Furthermore, salivary Aβ 42 concentrations increased across cognitive status categories and remained significant after adjustment for demographic, systemic, and oral health factors (ANCOVA p = 0.003). Multivariable regression identified unstimulated salivary flow rate as the strongest independent predictor of salivary Aβ 42 levels (β = −0.498, p < 0.001) Conclusions: Preserving occlusal support rather than solely focusing on replacing missing teeth may be relevant to cognitive health maintenance in older adults. These findings also support the potential role of salivary Aβ 42 as a non-invasive extracerebral biomarker of neurodegenerative disease, such as Alzheimer's disease.