How Brushing Your Teeth Hurts
"The action of brushing your teeth, especially with an electric toothbrush, actually pushes these organisms beneath the skin in your mouth," says R. Thomas Glass, DDS, PhD, professor of dentistry and pathology at Oklahoma State University Center for Health Sciences.
Since many of these germs are on your toothbrush because they were already in your mouth, they may not cause new disease unless shared with others. But he says they play a role in recurring illness.
"When your resistance is low, that's when this becomes clinically important," he says. "In essence, you are reinfecting yourself."