When they become an orthodontist! Orthodontics is just one of the 7  different dental specialties practiced, but only a fully qualified dentist is permitted to undertake the extra study required to become a specialist. Orthodontists are the most qualified people to diagnose, prevent and treat any problems you might have with your tooth and jaw alignment, and bite problems like overbites and under bites, because they have spent an extra 3 years in school learning about them! In Australia, an orthodontist must: Complete a five-year, full-time Bachelor degree in Dentistry. Complete a three-year, full-time specialist degree in Orthodontics.  Called a Doctor of Clinical ...