Whitening procedures help remove discolorations and stains from teeth and make them visibly white. Teeth can get discolored by stains which can be either intrinsic (dental fluorosis and tetracycline stains) or extrinsic (tobacco, alcohol, and tea or coffee stains). Teeth whitening is more effective on extrinsic stains than extrinsic stains. There are two types of tooth whitening procedures, namely in-office and at-home whitening. Your dentist does in-office bleaching in the clinic. The bleaching gel that the dentist uses is concentrated and strong. At-home bleaching includes tooth whitening strips and gels, tray-based bleaching, and whitening toothpaste. Both these techniques use peroxide-based tooth bleaching products.