The whole orthodontic process consists of two phases, orthodontic and retention, both of which are equally important. During the retention phase, you must wear your retainer carefully as required by your doctor, otherwise it will definitely lead to tooth relapse. The retention phase should be noted: ① Generally, the period of wearing the retainer is about 2 years, during which you should have regular follow-ups, one month between the first follow-up and every three months thereafter. The recommended wearing time is 24 hours for the first year except for eating and brushing; then you can wear it at night until you stop wearing it after the doctor agrees. Liu Yuehua, Department of Orthodontics, Shanghai Municipal Institute of Stomatology ② Under special circumstances, the retention time should be extended appropriately, and very few patients need lifelong retention. Such as twisted teeth, scattered gaps, incisor gaps, crowded lower front teeth, hereditary misalignment, adult patients, etc. need longer retention time; periodontal disease patients need to wear retainers for life after correction. Do not use hot water or chemicals, otherwise it will cause the retainer base to be deformed and cannot be worn. Please do not adjust the retainer wire parts by yourself to avoid extrusion and deformation. If the retainer is damaged, deformed or lost, please see a doctor for a new retainer. If the retainer is damaged or lost due to human factors, you will be responsible for the cost of rebuilding the retainer. ④You should wear and keep the retainer in strict accordance with the doctor’s prescription and review it as scheduled. You are responsible for any changes in the position of your teeth that occur within the prescribed retention period due to your own cooperation (e.g., not wearing the retainer as prescribed, not reviewing it on time, not reporting the breakage or loss of the aligner to the doctor, etc.). If you request a new orthodontic treatment, the cost will be treated the same as the initial patient.