Tooth decay among 2- to 5-year-olds increased from 24 percent to 28 percent between 1988 and 2004, says the U.S. Department of Health & Human Services. Keeping your child’s baby teeth healthy is important: Even though baby teeth are temporary, harmful bacteria from decayed teeth can affect adult ones later in life. Starting good habits early leads to a lifetime of healthy teeth. Clean your infant’s gums after each feeding with a wet infant washcloth, recommends the American Dental Hygienists Association. Start teaching your child how to brush properly by age 2 or 3.