The steps of cold light teeth whitening are as follows: 1. Firstly, basic periodontal treatment, that is, before cold light whitening, first confirm that the patient’s gums do not have any bleeding or inflammation, and there is no large pieces of calculus, plaque, etc. present. If there is, basic treatment is needed, which is carried out by the relevant professional doctor, and cold light whitening is then carried out in a healthy state of the gums; 2. Patients need to wear special eye protection mirrors, and teeth and gums should be coated with the corresponding protective material to prevent the chemical from stimulating the gums; 3. After the corresponding isolation, the tooth surface is coated with the chemical desensitizing drug of the corresponding whitening instrument, and then the cold light whitening instrument is used to The specific irradiation will be performed. Depending on the whitening instrument of different manufacturers, it may take 2-3 irradiations of 10-15 minutes each to achieve clinically better results. If the patient experiences tooth sensitivity during the whitening process, the doctor can shorten the treatment time accordingly. After patients undergo whitening, they should also pay special attention to their diet after going home, and try to eat less food that is easily colored in order to maintain relatively long results.