The control of bacterial dental plaque through daily oral hygiene is essential to prevent oral diseases such as caries or periodontal disease, especially in at-risk populations, including the elderly with mild cognitive impairment and dementia. The aim of this study was to determine the association between different levels of cognitive impairment and dementia in an elderly population and their capacity to maintain adequate oral hygiene. A case-control study (elderly with versus without mild cognitive impairment or dementia) was performed in Granada, Spain. Outcome variables were tooth/prosthesis-brushing frequency/day, bacterial plaque index, and gingival bleeding index. Statistical models were adjusted by age, sex, educational level, and tobacco and alcohol habits. The study included 240 cases and 324 controls. The final model, adjusted by age, sex, educational level, and tobacco and alcohol consumption, showed a significant association between degree of cognitive impairment and daily oral hygiene, accumulation of bacterial plaque, and gingival bleeding. In summary, deficient daily oral hygiene, evidenced by greater bacterial dental plaque accumulation and gingival inflammation, is independently associated with cognitive impairment, even at its earliest stage.
