The question of whether dentists can tell when someone has given head is a matter of debate. Some people believe that dentists can tell because they can see signs of oral sex on a person's teeth and gums. Others believe that dentists cannot tell because there are no definitive signs of oral sex that can be seen during a dental exam.
There is some evidence to support the claim that dentists can tell when someone has given head. For example, one study found that dentists were able to correctly identify people who had given head with 80% accuracy. However, this study was small and has not been replicated.