If you know that something unpleasant will happen, that you will go to the dentist for example, or to France, then that is not good. ✬

You ought to see a dentist. ✬

How often do you have to see the dentist? ✬

Tom should have gone to the dentist yesterday. ✬

You'd better see a dentist at once. ✬

I have an appointment with the dentist at 3 o'clock. ✬

I go to the dentist every second day. ✬

I go to the dentist's every other day. ✬

I had my teeth examined at the dentist's. ✬

I've been to the dentist's. ✬