What my dentist did for my teeth and and just for a cleaning and fillings he called my pain doctor to find out of how to treat me. He totally sedates me along with a ketamine drip, strong morphine before and after the prceedure. He also numbs the area before the filling and before I wake up so its numb longer. He is and anesthesia dentist and has like 4-5 different ways of sedating someone from just laughing gas to totallying puting you out where you use a breathing tube thats what I do. But my RSD is full body and internal and any slight injury could send me into the hospital. This is the same thing they do just for an MRI. Iam not sure if your dentist does sedation and keeps pain meds in hand but thats something that should be at least close to hand. Everyone is different in what they need or can tolorate to get through a proceedure.