The question of "can a dentist tell if someone gave head" is a common one, but there is no definitive answer. Some dentists believe that they can tell, while others believe that it is not possible. There is no scientific evidence to support either claim.
Those who believe that dentists can tell point to the fact that they can see the inside of the mouth and throat, and that they can feel the muscles in the jaw and neck. They argue that these factors can give them an indication of whether or not someone has engaged in oral sex.