There are many causes to tooth discolouration. Some of the most common include the consumption highly coloured food and drinks. Some medication, aging, smoking and trauma can also cause teeth discolouration. The quickest, easiest way to whitening your teeth is in-office treatment. It is dentist supervised, safe, effective and clinically proven to whiten up to eight shades (colour). For a brighter, whiter smile in just one single visit.