D.M.D is a Doctor of Dental Medicine. D.D.S is a Doctor of Dental Surgery. There is no practical difference between a D.D.S and a D.M.D. The curriculum for each is identical. Each dental school chooses which degree to award its graduates. As long as the school is accredited, the graduate is eligible to sit for the national board, as well as any regional board or state licensing board.
Any licensed dentist is allowed to perform any dental procedure, provided they have not limited their practice to one of the dental specialties (oral surgery, orthodontics, endodontics, etc.). The University of Florida College of Dentistry, where I attended, awards the D.M.D degree. Dentists in Canada tend to have B.D.S. degrees (Bachelor of Dental Surgery).