They are the same. Dmd and dds are the two degrees that are offered to dentists in the usa. Dmd vs dds is determined by the state's law. For example, a dentist graduating from massachusetts will always receive a dmd and a graduate from new york will always get a dds. All the credentials are exactly the same and both are allowed all practicing privileges in all 50 states once they pass their board certification.
Different schools. A doctor of dental medicine and a doctor of dental surgery are trained in similar manners. Older institutions generally grant a dds while newer ones prefer the dmd degree. All dental programs have to pass accreditation standards and all dentists have to pass clinical licensure exams to be granted a license to practice. So there is no real difference.
No. There is nothing diffirent about the the two degree's except the school you go to, as dmd is mainly given in the north east and the rest of the country gives a dds.