If my horses get a manual float they do not get sedated, nor do any of them need a twitch. All four of them stand politely with just a halter and lead rope. They aren't happy but they don't offer to fight either.
I was fortunate in the early days of all their training, to have a vet willing to take the time to work with them, sans the twitch because I wasn't allowing it
I also did a lot of fussing with their mouths in-between dental visits, and still do.
If the power tools have to come out, they get sedated. Sedation is the safest thing for everyone involved in case the horse would jerk.