I actually did research on how to keep your teeth clean if you don't have access to a toothbrush or toothpaste! I needed the info for a story, but thankfully it also has real world applications. Maybe something here will help:
If the bristles are a sensory nightmare, try a soft cloth instead. Cloth was one of the methods used before toothbrushes were invented, although they used shit like burlap. Don't do burlap. Cotton or linen should do fine.
You can also buy natural toothbrushes made with bamboo and boar hair. I've never tried them so I'm not sure how different they'd feel compared to synthetic bristles, but they're pretty cheap on Amazon if you want to give them a shot
If even the "extra soft" bristles are too stiff, you could try soaking them overnight in some mouthwash to soften them further. This is what we did when I was growing up, and it worked like a charm. Bonus points that the alcohol in the mouthwash kills any germs stuck on the brush
If the toothpaste flavor is horrendous, make a paste with baking soda and water, then flavor it however you want with a sugar-free extract. Heck, look for recipes to make your own toothpaste, and experiment until you get something you can stand to use.
If the texture of the toothpaste is bad, the baking soda method might work better for you, or you could try scrubbing salt or activated charcoal on your teeth instead—that's what they used before toothpaste was invented. Personally, I'd recommend the baking soda or making your own toothpaste.
Different brands often have different textures, and some even have different flavors (this is especially true of kids toothpastes, which work just as well for adults), so swapping brands might help, too. I can't stand Crest, it makes my mouth feel all filmy no matter how well I rinse, but Colgate doesn't leave a weird feeling in my mouth. Also Colgate is the only brand my grocery store carries that has cinnamon flavored toothpaste as an option, and I'm a whore for cinnamon
You're probably using too much toothpaste anyway. Most people do. You really only need a dollop about the size of a pea. I smush it out across the bristles so I don't have to deal with a glob of it in one spot.
Floss if you can. That's going to do more to stop your teeth from rotting than brushing will. Standard dental floss is obviously an option, but if you're like me and you can't stand putting your hands in your mouth, try disposable floss picks or investing in a water flosser. I still hate the feeling of the floss between my teeth, but it's manageable since I don't have my fingers in my mouth on top of it. Haven't tried the water flosser since the picks work well enough for me
Try chewing sugarless gum, especially right after you've eaten. It's not perfect, but it'll help. Also it comes in a billion flavors so hopefully there's something you like in there
If absolutely none of that is helpful, rinsing with water is still better than nothing. You can mix in salt to help kill bacteria if you can handle it, but bare minimum try to do a rinse and spit.
Obviously not all of that is from my pre-modern teeth cleaning research—some is from personal experience! But hopefully something in there is useful to you
It's absolute bullshit that we have to approach these problems sideways because the people actually making "helpful" articles about it are all ableist :| Maybe some day soon we as a society can get over that.
