The lightening of colour of the tooth through the application of colouring agent to oxidise the organic pigmentation of tooth is reffered to as tooth whitening or bleachning, teeth exhibitng yellow or intrisic disclouration appear to respond to vital bleachning (tooth whitening), where as tooth demonstrating bluish grey are often difficult to treat in this manner, upon completion of bleachning procedure the induvidual should be provided with a non-steriodal anti-inflamatory drug for senstivity