Tooth discoloration creates a wide range of cosmetic problems and and the public strive for a more esthetically pleasing appearance, considerable amounts of time and money are being invested in attempts to improve the appearance of discolored teeth. The methods available to manage discolored teeth range from the removal of surface stain, bleaching or tooth-whitening techniques and surgical techniques to camouflage of the underlying discoloration, using veneers and crowns. The use of a variety of bleaching techniques has attracted most interest from the dental profession because these techniques are non invasive and relatively simple to carry out. Contemporary bleaching systems are based primarily on hydrogen peroxide or one of its precursors, notably carbamide peroxide, and are often used in combination with an activating agent such as heat or light. Bleaching agents can be applied externally to the teeth (vital bleaching), or internally within the pulp chamber (nonvital bleaching). Both techniques aim to bleach the chromogens within the dentine, thereby changing the body color of the tooth