This is just something you will need to speak to your dentist about. It seems to me that they are working with your anxiety as best they can. I can see why you need to be monitor if they are using anything to put you to sleep this is for your safety.
The valium may be an option but you will still need to check with your dentist to see if they will use it and not monitor you. I advise to go to your appointment early ask all the questions you have a head of time so that you can feel comfortable with what will or can be done.