I don't know what your favorite color is, but when it comes to your teeth, I bet it's not yellow!
Yellow teeth can be caused by many things, but cigarettes and coffee are the top offenders. Just as a cigarette filter picks up a yellow stain, so do smokers' teeth. Coffee can stain your shirt - and your teeth. So can tea and cola.
In fact, almost anything that can stain fabric or dishes can stain teeth too. Any highly-pigmented food or beverage can leave its mark on your pearly whites. (Something to think about the next time you order curry!)
But there's good news if you want to brighten your smile! Tooth whitening actually works best on yellow teeth. While grey or bluish discolorations can be very difficult to remove, most yellow stains disappear quickly with teeth bleaching treatment.
After teeth whitening, you'll want to try to maintain that brilliant white smile by minimizing your exposure to stains. You can still enjoy coffee or tea, but it's better if you drink them relatively quickly and rinse afterwards; sipping coffee slowly throughout the day will add more stains to your teeth.