You need to find a cup/glass with you every time you brush your teeth or you just simply gobble up water from the faucet? Here is a new toothbrush designed by Amron Experimental called Amson Rinser Toothbrush gives you an alternative to carry water into your mouth like a high flowing fountain.
Additional snap-in bristles can be bought when the bristles are not functioning anymore. What you can do is just take out the brushing top which is made to pop off in an instant.
So, you still can keep using the fountain function and won’t need to buy the whole new toothbrush every time.