Dental surgeon = Dentist; they are interchangeable terms. I prefer the former, because it more accurately describes what we do.
You are referring to oral surgeons or oral and maxillofacial surgeons.
There is some variation in the pathways to become a maxillofacial surgeon, but they generally go like this:
1. Complete dental degree.
2. 1-2 years or more - hospital dentistry and general dentistry, formally increasing oral surgery experience as you do this
2a. Complete RACDS Primary examinations
3. 3-5 years - complete medical degree (often, doing hospital dentistry work at the same time, with a special focus on oral surgery)
4. Complete medical internship
5. Complete at least 1 year of surgery in general residency and associated entry level surgical exams
6. Apply for RACDS Max fac program, if accepted, acquire registrar position
7. RACDS max fac program takes minimum 4 years to complete
Total training time including dental degree: minimum 15 years.