To be a orthodontist you must have four years of college, four years of dental school and two to three years of post-graduate orthodontics training, as well as extensive written and clinical certification and licensing exams. to be pediatric dentist you have to have high diploma in addition to a bachelor's degree that includes some pre-dental study and a DDS or DMD degree from a 4-year dental school. According to the American Association of Pediatric Dentists, dental school graduates must receive an additional 2-3 years of education in order to practice pediatric dentistry. A oral surgeon must have a takes four years and includes both theoretical studies and clinical work. For two years, students take classes in anatomy, biology and health sciences, concentrating on the teeth and the mouth. Students also study radiology, periodontology and anesthesia.