Dentistry – Graduate Specialization Programs
Medical Residency in the United States – International Medical Graduates (IMGs)
ECFMG stands for the Educational Commission for Foreign Medical Graduates and is an independent organization that certifies foreign medical graduates in order to do a medical residency in the U.S. www.ecfmg.org
For step-to-step instructions on testing and the certification process see here. Review the material thoroughly so that you can understand the procedures involved (ECFMG) and the format of the tests (USMLE).
You may also wish to look at a Quick overview of the Residency Application Requirements for International Medical Graduates (from the American Academy of Family Physicians)