The process of orthodontic treatment is relatively long and requires close cooperation between the patient and the doctor to achieve the desired results. Many patients worry that orthodontic treatment will loosen the teeth and reduce the service life of the teeth. In fact, orthodontic treatment is a kind of movement of teeth within the physiological range, except for a very small number of patients with special constitution, which will cause obvious root resorption due to treatment, it will not have obvious impact on dental health. However, orthodontic treatment increases the burden of teeth, and increases the difficulty of oral cleaning due to the presence of orthodontic attachments, if the oral hygiene maintenance is unfavorable, it will promote and aggravate gingivitis and periodontitis, and secondary dental caries. If oral hygiene is not maintained properly, it will have irreversible effects on dental health. Some patients are hesitant to have orthodontic extractions because they are concerned about the adverse effects of a reduced number of teeth or the inability to close the extraction gap. In fact, many malocclusions occur because the jawbone cannot accommodate the existing teeth. Tooth extraction is to create a gap so that the teeth can be aligned and the bite can be adjusted to achieve aesthetic and functional perfection, which is good for oral health and does not leave a gap. Before orthodontic treatment begins, patients should prepare themselves as follows: 1. to understand the necessary knowledge and clarify their treatment requirements. 2. 2, know that there is a physiological limit of tooth movement, orthodontics takes a long time, need enough patience. 3, orthodontic treatment process aligner 24 hours a day in the mouth, may affect the aesthetics and eating, in order not to damage the aligner, but also need to change some habits in the diet. 4, orthodontic treatment process may have some pain or discomfort, brushing may also be more troublesome, may also need to hang rubber band, etc., in order to oral health and perfect treatment results, need to pay enough patience and efforts. 5, to be able to adhere to regular follow-up visits and good cooperation, which is essential to the treatment results. 6.Know your orthodontic appliance, be able to find abnormalities and contact the doctor in time, not to handle it without permission or ignore it. 7, orthodontics after the need to maintain, conventional 1.5-2 years, some patients need longer or even lifelong depending on the situation.