Why fix baby teeth when they’re just going to fall out? Some baby teeth may stay in until the age of 12! Baby teeth help the child chew, swallow and talk. They aid with the development of the jawbone, providing protection and guidance for the permanent teeth developing below plus proper spacing in the jaw. If a cavity in a baby tooth is left unattended, it may continue to expand and cause an infection in the gum. This, in turn, can cause facial infection or damage to the adult tooth underneath it.