Many patients start to see a difference in the color of their teeth after just a few whitening treatments. As for how long your results will last, it varies from patient to patient. Patients who drink a lot of coffee, red wine, and dark-colored sodas may notice that the whiteness of their teeth fades faster than they would like it to. The effects of professional teeth whitening should ideally last for several years, and you can always get another treatment if your teeth become stained or the brightness starts to fade.