>>890664
Should use only the softest toothbrush. And don't need to scrub like a madman, you won't make your teeth white no matter how hard you try.
And use soap as mentioned. Soap cleans. That's why it was invented and used (in basically every cleaning product).
Teeth decays from two things (besides the aforementioned calcium "withdrawal"):
1. acids - the stuff you consume, food and drinks, and from the acids bacteria (and yeast fungi) produces from the carbohydrates you consume;
2. mechanical "milling/grinding" - by food, and by you brushing it.
If your mouth ph is acidic, the mechanical impact grows. Should rinse your mouth with water, or something with basic ph (such as a pinch baking soda solved in a half a deciliter of water), after consuming acidic stuff.