I went to the dentist's office last week.
I had a fantastic visit. I warned they hygienist that I was tired and that I might fall asleep. However, I was also worried that I wouldn't be able to keep my mouth open.
She came up with a great solution. There was a little foam block that she found. We wedged it between my molars to keep my mouth open. I must have been really tired, because I DID fall asleep for about half an hour.