What happens if a child refuses to go to the dentist, can a parent force them? The Tzitz Eliezer (20:47) says that the obligation on a parent for his child’s well being is the same as his obligation to feed him. We see this from the Chasam Sofer who treats these two aspects of care identically with regard to husband’s obligation to his wife.Therefore says the Tzitz Eliezer a parent can force his child to go to the dentist until he reaches his 14th year (13 years old) and a girl her 13th. After that the child can refuse.
However he says, the parent is not quite off the hook once the child refuses. We see from the gemara in Kedushin that a father must be rebuke his child from age 16 to 24, as these are the years where the child is smart enough to understand and the parent has the most influence. After that it is too late. Similarly says the Tzitz Eliezer, the parent must uses all his tools of persuasion to convince the child to do what is right.
Additionally, says the Tzitz Eliezer, you must help him make the right the decision based on the halachos of Hashavas Aveida. Chazal teach us that just like you are obligated to help you friend recover a lost item, surely you must not sit by idly when his health is at stake. This chiyuv applies to all people, blood relatives or not, and regardless of age.