Crowns? Try implants.
If you want your mouth REALLY clean, start out with hand sanitizer, rinse and spit. Follow with “Joy” lemon dishwashing liquid, brush vigorously, rinse and spit. Next, hydrogen peroxide, let it do its thing, brushing at the gum line.
If you lift your lip away, you will see a number of white areas on the gums, especially at the gum line, Dip your still-wet tooth brush into 20 Mule Team Borax, take a mouth full of water, and again brush pretty thoroughly. Include the insides of the cheeks and the tongue. Rinse and spit, a couple of times.
The next drink of water you have, straight from the tap, will taste like the cleanest, freshest water you ever sipped.
You are no longer tasting the inside of your mouth, but water as it REALLY tastes.
I brush with baking soda straight out of the box.