The letters after a doctor’s name are designations for the credentials they have earned. All U.S. based dentists will have earned either a D.D.S. (Doctor of Dental Surgery), or D.M.D. (Dentariae Medicinae Doctorae, Latin for Dental Medical Doctor) degree. There is no difference between a D.D.S., and a D.M.D. The M.S. represents a three-year long Master of Science degree; C.D.T. is awarded for anyone who has passed all the requirements to be a Certified Dental Technician; and F.A.C.P. indicates that a Prosthodontist has earned Board Certification and has achieved the coveted honor of becoming a Fellow of the American College of Prosthodontists.