Ok, good explanation, thanks. I was trying to figure out what's going on here, exactly.
To answer your question, our dentist(s) recommend electric toothbrushes because they think they do a better job than brushing with a regular toothbrush. I don't have space in my bathroom for a big set up so I buy the cheap ones at
WalMart for my kids and they stay in the regular supply basket I have on the counter. The dentists have said this is fine. The important thing for them is good brushing and flossing. I use a regular brush (and floss a lot, and have cleanings every six months, so my plaque buildup is minimal).
I buy the floss sticks. I started buying them for the kids when they were little to help them learn how to floss and we all use them now. They're easy. DH and I still use regular floss, too. My old dentist had a big sign on the wall saying, "Only floss the teeth you want to keep". So flossing would help keep plaque down in your mouth so cleanings aren't so stressful for you. Definitely give it a try.
As for the deep cleaning, I think you and I are both talking about what I consider a regular cleaning, which is when they basically remove the plaque off your teeth. I've never had a cleaning where they didn't do that. (Maybe they just polish your teeth because you don't want to have the rest?) Anyway, as I said, my new dentist uses a high powered water cleaning system, and she does the cleanings herself. I had it done for the first time a few weeks ago and it was kind of nice. No picking. Can you look into something like that?
I know you want an exact answer of whether you feel pain with relaxing medication, but people are trying to say that they're too out of it to feel pain. Your brain's wiring on the drugs makes you unaware. (This is how opioids work, actually - they don't relieve pain, they just alter your perception of it, and as most people know, they are VERY effective!) So that IS your answer.
I am sympathetic to your plight - I had bad experiences when I was young, too. (Think gassed and being held down in the chair repeatedly.

) In adulthood I have sought out kind and gentle dentists who are empathetic. They are out there, you just have to find them. They understand dental trauma and anxiety. You might see if you can find a dentist who will treat you completely him or herself, i.e. one who will do the cleaning, too, as opposed to the hygienist - unless you can find a really great kind and patient hygienist. Maybe look for reviews online.