Bleaching is successful in at least 90% of the patients. Consider bleaching if your teeth are darkened from age, coffee, tea or smoking. If you are in a hurry for whiter teeth, you may decide to have your teeth lightened immediately through an in office procedure. However, most patients choose dentist-supervised at-home bleaching, which is more economical and provides the same results without sensitivity. Lightness should last from 1 to 5 years and can be touched up at any time. Several studies have shown bleaching to be safe and effective.