You could say:
Do you feel like going to the dentist? or
Don't you feel like going to the dentist?
In both of these questions you are asking another person about what they want to do. The second one is probably more likely to be used if you think that the person does not want to go there. There are other ways you could ask this question.
Would you like to go to the dentist? (Probably used if you are offering to take them)
Shouldn't you go to the dentist? (Used if you think they should go. For example, if they've been complaining of a toothache)
Hope this helps!