Retainers are worn to maintain the teeth in their normal position after orthodontic treatment. Retainers are removable and can be removed by the patient. Patients should wear and keep the retainer in strict accordance with the doctor’s instructions, if it is broken or deformed or lost, please contact the doctor in time. 1.The use of retainer ①When you wear it for the first time, you may feel uncomfortable and even affect your speech, but everything will be normal within a few days. ② Retainers generally need to wear about 2 years, such as before orthodontic treatment for reversed teeth, scattered gap, central incisor gap, lower incisor crowding or teeth misalignment with periodontal disease, etc. need to maintain a longer time, or even need to wear retainers for life. Chen Jie, Department of Stomatology, Shanghai Xinhua Hospital ③ Wearing time is recommended: 24 hours for the first 12 months, only at night for the middle 6 months, and 2-3 nights a week for the last 6 months. The retainer should be removed when eating and brushing. ④Retreatment during the period of retention: one month between the first retreatment and once every two months afterwards. 2.Maintenance of retainer ①Take off the retainer and soak it in cold water, use toothpaste or detergent to clean it. ②Do not use external force to squeeze or hot water or alcohol to rinse the retainer, otherwise it will lead to its deformation. ③ keeper to take off temporarily not wear, it is best to put in a hard plastic box to avoid deformation or loss. Third, remind 1, the first wear orthodontic appliance and each follow-up after the force, the oral mucosa may be worn, the teeth may appear mild reactive discomfort or pain, generally lasts 2-3 days to reduce or disappear, if the pain lasts 4-6 days does not reduce or even aggravate, please contact the doctor in a timely manner for medical examination. 2. If you find that the ring or bracket is loose or the arch wire is broken, you should contact the doctor in time for a checkup. Do not move or adjust the wires on the aligners by yourself to prevent loosening and necrosis of the teeth, which will affect the treatment.