Use what makes the horse happy and it functions the best.
Sometimes thick tongues, palette issues, or tooth issues can cause a horse to reject any sort of bit.
I have two who wear mechanical hackamores and two who wear low port curbs with swivel shanks. Back when I was hard trail riding, they all did the same amount of sliding down a river bank, digging up the other side, riding on the flat of an old railroad bed, down a country road, yadda yadda.
Meaning, tooth/mouth issues or not
A properly trained horse with a tactful rider should be able to go in any of those well and without being in pain.
The operative in that quote being the TACTFUL RIDER. If your hands are rough, you aren't getting anything but trouble out of the horse, no matter what goes on its head or in its mouth