Well for myself I just finished off invisalign and have regular 6 month cleaning plus I had one cavity filled. I have rsd in my legs and eyes we think plus seems to be spreading but not to the mouth. For myself my dentists were informed about RSD. I explained the condition completly and how it can spread to even the mouth. That uneeded things that can cause inflammation or pain can't be done. I always even if the doctor says they know what RSD is I still explain it because I know a couple who said they did but really did not. With my filling he said he did it in a way that caused the least inflammation and my orthodontist with the invisalign was extra gentle etc. I did not notice a difference in my actual rsd areas on or after the apt.
You should not need any numbing injection or sedative for a cleaning. I never get one. You are supposed to go for cleaning every 6 months. The apts are not long so not sure what you mean by that.
I understand your concerns though trust me