Please, explain to the dentist about your fear. It's very important that you and the dentist understand each other.
If you have the talk and don't get results, then change dentist until you find one that understands and will work with you to make you comfortable.
You see, I had a fear of the dentist for a long time. Finally met one in a bar who promised me I wouldn't feel a thing. I was lucky to find this guy and he fixed all my teeth and to this very day, I actually look forward to my checkups.
For we wrestle not against flesh and blood, but against principalities, against powers, against the rulers of the darkness of this world, against spiritual wickedness in high places.