Unfortunately, Strep mutans can be transmitted through saliva. In fact, it is transmitted from mother to child when, for example, Mom picks up a pacifier from the floor and “cleans” it by putting it in her own mouth and licking it before giving it to Junior . . . or when she eats food from little Luke’s spoon, saying “Yum!” to motivate him.
In both cases, a mother with Strep mutans just transferred the bacteria to her child. Based on pH and genetic factors, the baby may or may not develop tooth decay, but why take a chance? Wash the pacifier with soap and water, and pretend-eat to motivate the child at meal time.
Needless to say, kissing that involves an exchange of saliva can cause similar contagion between adults. (This is also true of gum disease, as we’ll see.)