With the advent of new treatments, a better smile is now within reach of more people. One of the most popular cosmetic procedures is bleaching. The natural light ivory color of enamel can turn to yellow, orange, brown, gray even blue or green. Causes of discoloration include staining from coffee or tobacco, an injury that has damaged the pulp, ingestion of the antibiotic tetracycline or high levels of fluoride while the teeth are developing, corrosion from silver fillings, and the natural wearing away of the enamel with age. Although many stains can be successfully removed with a bleaching technique, bleaching may be uncomfortable for people with sensitive teeth or an exposed root. Several different bleaching techniques are available.