The methods used to lighten tooth discolouration while conserving the tooth structure have attracted much attention in a society which places a high value on esthetics. The purpose of this article is to present a home bleaching agent that uses a film-forming preparation containing carbamide peroxide (CP) which, while degrading, serves as a slow release delivery system of the bleaching agent. The efficacy of the preparation containing 3% CP and 10% CP on reduction of tooth discolouration is evaluated by a Chromameter in a double-blind placebo-controlled study. The effect of the tested bleaching agent on the gingival status, plaque accumulation and pulp sensitivity is also assessed.