Can a kiss lead to a cavity? Yes, says Middleton, Wisconsin, Dentist Chris Kammer, president of The American Academy of Oral Systemic Health. He contends that cavities can be caused by bacteria that are passed from one person to another, just like a cold or the flu.

“We aren’t born with tooth decay-causing bacteria,” says Kammer. “At some point, it is introduced to us from an external source, usually a family member,” through sharing food utensils, licking pacifiers, kissing and more. “Then it takes up residence in our mouths, where it is fed by sugars, which cause the bacteria to produce acid.”

Cavity-causing bacteria can be transmitted by sharing food, by drinking out of the same glass and by toothbrushes that make contact with the bathroom counter. If bacteria is not removed from teeth (existing in a protective biofilm called plaque), the acid byproduct is able to directly reach and soften tooth surfaces, creating the holes called cavities.

Easy solutions to the problem start with good oral hygiene for both parents and kids and proper brushing from a very young age, starting with finger brushing as soon as the first tooth erupts. Kammer advises making it fun and thus habit-forming when kids become old enough to do it themselves; one new interactive toothbrush times kids to ensure they brush the dentist-recommended two minutes.