Prograf and cavities; do people get bad teeth and gums problems?

Not really: I am unaware that transplant recipients who take immunosuppressive drugs including tacrolimus will have trouble with dental hygiene; as long as you listen to your dentist and brush and floss your teeth as instructed, and get timely examinations.

Not specifically but: Not specifically from the use of Prograf (tacrolimus), but it might be possible that immune suppression could leave you more vulnerable to infection generally, so really careful hygiene is important, as well as regular dental checkups.