A pediatric dentist is a dentist who has had a specialized education to only treat children.  The doctor goes to dental school, like a general dentist, but in addition they do a rigorous two-year residency to learn how to communicate with, educate and treat children of all ages, including those with special needs or behavioral concerns.  A child's mouth and dental needs are vastly different from an adult, they are not "mini adults" and therefore need an atmosphere and a dentist who can uniquely tailor dental care to their individual character.