If you already had your degree before you began the internship, then I think it probably wasn't part of your degree.
Try thinking of it like this:
If you had not done that internship, would you still be qualified to do the job you're currently doing ?
Was it possible for you to graduate, then immediately get a full-time paid non-internship job ?
If yes, then I think the internship will count as work experience.
But I'm not a dentist, so I don't really know how your qualification program works.