sweetness. truvia sweetener. zero-calorie sweetness, born from the stevia leaf. from nature, for sweetness. like other precious things that start off white, it yellows over time. fact is, when it comes to your smile, if you're not whitening, you're yellowing. crest 3d white whitestrips go below the enamel surface to whiten as well as $500 professional treatments, at a fraction of the cost. guaranteed, or your money back. crest. life opens up when you do. want a whiter smile today? try 2 hour express whitestrips.