Effects of oral health interventions on cognition of people with dementia: a systematic review with meta-analysis

Increasing studies have shown that poor oral health contributes to the progression of dementia. It is meaningful to find out the role of oral health interventions in maintaining people's cognition levels and delaying the progression of dementia. Thus, we conducted this review to summarize the present evidence on the effect of oral health interventions on the cognition change of people with dementia. Literature search was conducted in the databases of PubMed, Embase, Web of Science, Cochrane library, and Dentistry and Oral Sciences by two independent reviewers from inception to 6 March 2024. Clinical studies such as randomized controlled trials reporting on the effect of oral health interventions on the cognition of people with dementia were included in this review. Mini-Mental State Examination (MMSE) scores were used to measure cognition level. The mean deviation (MD), generated by subtracting the baseline MMSE score from the MMSE score at follow-up was used to assess the change in cognition. Studies with oral hygiene practice as an oral health intervention were further conducted with a meta-analysis. A total of 6646 references were identified by the literature search, and 5 studies were eligible to be included in this review. Among the included studies, 4 studies reported the cognition change after having various oral hygiene practice as oral health intervention, while the other study adopted oral exercises as the intervention. Two studies presented positive MD values after intervention provided, indicating improved cognition level at follow-up (MD = 0.6, MD = 0.9, respectively). Another two studies reported less cognition deterioration with smaller absolute MD values in the intervention group, (intervention vs. control, -0.18 vs. -0.75, p