Those little blue microbeads in your Crest toothpaste may be getting stuck in your teeth and gums, prompting dentists to ask toothpaste manufacturers for a change. The tiny scrubbers contain the ingredient polyethylene, a form of plastic that does not degrade and can stay embedded in your mouth. “Your body will see them as a foreign body, bacteria will clamp to them and it has the potential to cause gum disease, some form of gingivitis or harm to it,” Dr. Wade Pilling of Meri