Teeth should be cleaned before cold light teeth whitening and a basic healthy periodontal should be maintained before any treatment is done. If a patient’s gums bleed when brushing, it indicates a periodontal problem and requires a basic treatment to remove periodontal calculus at the appropriate professional. Patients with periodontal disease even need appropriate treatment to achieve healthy gums and healthy periodontium before they can undergo the appropriate treatment. When performing cold light whitening, bleaching medication needs to be applied, which will cause some stimulation to the special sensitive teeth, and if the periodontium is not healthy, this stimulation may lead to corresponding discomfort and even pain to the gums. Therefore, it is important to carry out periodontal basic treatment before cold light whitening, not just for the sake of beauty without regard to periodontal health problems.