Bacteria linked to gum disease traveled to the brains of people with Alzheimer’s, suggesting dental hygiene might play a role in the memory-robbing illness, British researchers said yesterday.

Signs of the bacterium, known as Porphyromonas gingivalis, were found in four of 10 brain-tissue samples of Alzheimer’s patients, while no signs were found in 10 brains from people of a similar age without dementia, said the study published in the Journal of Alzheimer’s Disease.