Most of us blame cavities on sugar, but the proximal cause is the acid produced by bacteria eating that sugar, which leads to a fairly icky question — can cavities be contagious?
Just as a cold virus can be passed from one person to the next, so can these cavity-causing bacteria. One of the most common is Streptococcus mutans. Infants and children are particularly vulnerable to it, and studies have shown that most pick it up from their caregivers — for example, when a mother tastes a child’s food to make sure it’s not too hot, said Dr. Margaret Mitchell, a cosmetic dentist in Chicago.
A number of studies have also shown that transmission can occur between couples, too. Dr. Mitchell has seen it in her own practice.
“In one instance, a patient in her 40s who had never had a cavity suddenly developed two cavities and was starting to get some gum disease,” she said. She learned the woman had started dating a man who hadn’t been to a dentist in 18 years and had gum disease.