Give the new one to one of your other kids, or use it yourself. Make a BIG DEAL about using it for the next couple days. Tell her to use the old one until you decide to buy her another one (of your choosing). Wait a couple weeks to get her a new one and then get the same one.
Or...throw the new one out (or put it away) and make her brush her teeth with the old one until everyone else gets a new toothbrush and then get her the same one again (or give her the one you put away). Tell her she will continue to get THIS SAME toothbrush until she is grateful to have one.
If she learns her lesson and doesn't complain next time...maybe reward her with the toothbrush she wants.
All this advice is from my dd - 16 yrs old.
