Figure 1: Traditional retainer (worn on the teeth, the wire is visible on the outside, the bracket is invisible on the inside but affects pronunciation) Ding Rui, Department of Orthodontics, Urumqi Stomatological Hospital Figure 2: Transparent pressure film invisible retainer (over the teeth) Figure 3: Lingual fixed retainer (fixed on the inner surface of the teeth, invisible and does not affect pronunciation) After 1-2 years of orthodontic treatment, each patient will enter the maintenance phase, cum retainer-wearing phase. Here is a brief introduction to the importance of retention. Through 1-2 years of orthodontic treatment, the teeth in the mouth are displaced, and the teeth relapse fastest within a year after the aligners are removed at the end of orthodontic treatment, which means that if the aligners are not maintained after removal, the teeth will have a tendency to change back to their original shape. Therefore, we emphasize that the end of active orthodontic treatment is only half of the orthodontic treatment, the other half depends on how well the patient cooperates with the retainer. In layman’s terms, if the retainers are not worn as required, the teeth will slowly become uneven again. We will make retainers for patients after treatment according to their requirements and their specific oral conditions, and there are currently three main types of retainers available. First, the traditional wire-and-base retainer, where a wire is visible on the outside and a base on the inner side of the tooth. This type of retainer can affect pronunciation to some extent due to its size, but has the advantage of being strong and durable, and allows for further self-adjustment of the tooth. The second type is the transparent invisible retainer, which has the advantage of being basically invisible, does not affect the aesthetics, is small and comfortable, and has little effect on pronunciation. The third type is the lingual fixed retainer, which is the smallest and most comfortable, fixed on the inner side of the teeth, the retention effect does not depend on the cooperation with the patient, and the aesthetics is also the best, the disadvantage is that it is more expensive, and it will be damaged if the patient does not take care of it or use it improperly. Among the above three retainers, the first two depend on the patient’s cooperation and require 24-hour wear throughout the day except for eating and brushing, and none of them can be squeezed, none of them can be subjected to heat, and absolutely none of them can be sterilized by boiling water. The third type does not require the patient’s cooperation and is fixed to the teeth, which is also more comfortable, but requires the patient to use it carefully so as not to break it. The following is a note of caution when the retainer is damaged or lost: Once the retainer is damaged or lost, contact the doctor in time to come to the hospital to re-bite the impression and recreate the retainer. Never delay for a long time, especially in the first year, the teeth are easily deformed. Another point to note is that the first two types of retainers should never be eaten when they are not removed from the mouth, as that will damage the retainer. If there is still something you don’t understand, please ask your doctor for advice.