Researchers from the University of California found that those women who brushed their teeth less than once a day were up to 65 per cent more likely to develop dementia than those who brushed three times a day, the Daily Mail reported.
"Not only does the state of your mind predict what kind of oral health habits you practise, it may be that your oral health habits influence whether or not you get dementia," Annlia Paganini-Hill, the study's lead author, said.
It's thought gum disease bacteria causes inflammation and brain damage when it reaches the brain.
The study followed nearly 5,500 elderly folk at a Californian retirement community from 1992 to 2010.
Some 18 years later, 1,145 of the original group had signs of dementia. Of 78 women who brushed their teeth less than once a day in 1992, 21 had dementia by 2010, about one case per 3.7 women.
In comparison, among those who brushed at least once a day, closer to one in every 4.5 women developed dementia