My camera is a Nikon 610. Full frame and it is also the camera that I used to do the video that was on the page about Dental Photography.
I only use the original Nikon lens. Of course, there are less expensive lens (Tamron, Sigma etc) but for me, the lens is even more important than the camera in itself. A macro 105 mm does a great job when we are talking about dental photography.
Ring flash or twins flash. Lately, I´m using the R1C1 and very happy with the result. You can see the difference in this clinical case.
A cheap solution that will provide a nice final touch to your dental photos. Try it!
Recommended Software for Dental Photography