How Does Oral Health Status Correlate with Cognitive Decline in Individuals with Dementia and Alzheimer’s Disease: An Umbrella Review

Background Issues pertaining to oral health have been recognised as a common concern among dementia patients. Past studies have indicated several mechanisms through which poor oral health could contribute to cognitive decline, such as systemic inflammation and direct effects on daily functioning and quality of life. Methods An umbrella review was conducted through an extensive search across a range of databases. The search strategy combined specific terms that would specifically pick out relevant studies for oral health and cognitive decline in dementia. A standardized tool to evaluate systematic reviews was applied to assess the quality and potential bias of the studies included. Results We included 8 reviews in our investigation, which revealed a complex relationship between oral health and cognitive decline in dementia. It was observed that poor oral health, characterized by high levels of dental plaque, gingival bleeding, and periodontal disease, was frequently associated with worse cognitive outcomes. There were some studies that focused on the inflammatory process as a bridge, while others stressed that oral health directly influences quality of life and cognitive performance. Variability in severity was noted for periodontal disease and its correlation to cognitive impairment, and in a few studies, a protective effect of good oral hygiene was reported. Conclusion The findings of this umbrella review confirm that poor oral health is indeed associated with cognitive decline among individuals with dementia. This association was mediated by pathways, such as systemic inflammation, which exacerbates neurodegeneration and directly impacts the quality of life and daily functioning. Such results underscore the need for comprehensive oral health care as well as regular assessments in the care setting for people with dementia as one potential way of preventing deterioration in cognition.