My mother needs to see a dentist, but I am afraid to take her out of the locked memory care unit where she has lived for a year. Any suggestions?

My mother is having problems with a painful spot on a lower denture. The denture was made by a doctor who does house calls but has never fit properly. Dentist has made a number of housecalls doing adjustments and, finally, a soft reline. It did not work. I called in another dentist for a second opinion. She did nothing except recommend a hard reline, but took no impressions. We have had some financial setbacks and the housecalls are really digging into our budget and have not produced resolution. I would like to take Mom to an office, but her behavior is unpredictable. The last two times that she was in a car, she had paranoid panic attacks. Also, she has not been outside of memory care for a year and is constantly asking to be taken home. A friend suggested that I ask her doctor for medication that would make a calm medical appointment possible, but I don't know what that would be. Mom recently lost her doctor and I have not yet been in touch with the assisted living doctor. Sometimes Mom's behavior is very good--other times it is not. I would like to take her to her dentist that she had seen for many years until the dementia made it impossible for her to continue living at home. But, I am afraid of the unpredictability, afraid that she will not get in or out of a car, go inside the dental office, cooperate with the exam, and go back inside the assisted living facility. I don't have any family members that would help with her.

Does anyone have any suggestions or experience with a situation like this?