International dentists have very few options and from what I've read most of them take the path to get a US undergrad and then apply to dental school like anybody else since the country in has no dentist shortage. For an IMG physician I'd assume you'll absolutely need to start the beginning since you degree won't fulfill any of the requirements for a dental application, let alone become a dentist without any dental schooling. You could continue studying for the USMLE or be in the same position as a high school graduate trying to be a dentist.