There are several methods of teeth whitening as follows: 1, cold light whitening, which is a whitening agent placed on the teeth and bleached under cold light; 2, whitening of white teeth commonly used in clinical practice, which is an American brand and can be done without cold light; 3, line porcelain veneers or resin veneers for whitening, you can choose the color you need for whitening, this whitening method will produce slight trauma to the teeth, you must have teeth preparation, cold light whitening and white teeth This whitening method will cause slight trauma to the teeth and must be prepared. The main whitening methods used now are cold light whitening and white teeth whitening, which can be somewhat sore when used. Patients can use anti-allergic toothpaste to protect their teeth when they choose to go to whitening, which can reduce post-operative reactions.