What's the difference between orthodontics certifications & orthodontics postgraduate MS?

My own orthodontist did not do a traditional 2 yr MS program in orthodontics. Instead, they received certifications from seminars with over 600 hours of continuing education in orthodontics. Other orthodontists in my town did the 2 yr MS. My own orthodontist is highly talented and gets more people and rave reviews in comparison to the other orthodontists. So I was just curious what were the differences between orthodontics certifications & orthodontics traditional postgraduate MS?
Source: Student Doctor Network - Category: Universities & Medical Training Authors: Tags: Dental Students Source Type: forums