elfbiter

Piers Anthony - Prostho Plus
(Repost from Livejournal)
Dr. Dillingham is a human dentist who suddenly has to treat a denizen of a flying saucer. After the successful treatment, the grateful proto-Greys abduct him and sell him in outer space. Poor doctor gets acquainted with number of (amusingly) alien species and their various dental problems. Eventually he finds himself in the Galactic University of Dentistry and faces its internal politicking.
( Major drilling work for Dillingham )