I have naturally yellow teeth which have never had any cavities, but I would love them to be white. I ve tried crest strips for 2 weeks but they did not work at all. Is there anything I can do to make them white? I can t afford a dental treatment and would prefer something I can buy at a drugstore, but I m not sure if it s actually possible to whiten my teeth. They are corn yellow in colour and slightly transparent at the tips. Crest strips only made them shinier, not whiter.