It doesnâ€™t take long for a thin layer of cement to dry and become so hardened it has to be jack-hammered away, but when it's just poured, it's easy enough to wash away with some gentle force. Plaque is the same way. As it's forming in the mouth, it's not hard to gently brush, rinse and spit away, but once it's hardened, tiny "jackhammers" and more than a little force are needed to chip it off our teeth. How can we be hard on plaque and banish it from our mouths while it's still soft? Test your methods and know-how here.