A dentist specializes in diagnosing and treating issues with the teeth and gums.
How long must a dentist go to university before he gets his degree?
Depends on what country the dentist is in I know in France and China the first dentist were actually barbers
That's interesting!  How did they get from being barbers to being dentists?
They were divided into two groups lay barbers and guild barbers, guild barbers were the dental surgeons.
What sort of surgery do the dental surgeons perform?
I am not sure but my dentist has a team working with him including hygienist and technicians
What teeth issues does the dentist treat, besides filling cavities?
Preventative cleaning as well as treating injuries, gum disease and other conditions of the mouth and teeth