Orthodontics has been around for 100 years. With the continuous improvement of aligners and orthodontic techniques, orthodontists can move teeth precisely and achieve good orthodontic results and stable outcomes. However, when aligners (especially fixed aligners) are inserted, the patient’s oral environment changes, especially in the teeth and surrounding tissues. If the existence of these changes is ignored in the treatment and not actively prevented, there is a risk of some adverse problems. The two main points are enamel demineralization and periodontal tissue damage. It is important to note that orthodontic treatment is not the direct cause of enamel demineralization and periodontal tissue damage. If we take a series of preventive and control measures, we can avoid the above problems. 1. Brush your teeth diligently: brush your teeth carefully after three meals every day for about 3 minutes, and the strength should be appropriate. If possible, use a special orthodontic toothbrush. 2. Rinse your mouth more: when you drink or eat and can’t brush your teeth immediately, you should rinse your mouth in time. But its role is very limited, can only rinse away the large pieces of food residue in the mouth. You can use mouthwash at the same time, but not long-term use. 3. Flossing: Toothbrush can only brush 70% of the teeth, the two teeth together where the toothbrush is unable to clean, the accumulation of dirt over the years is an important cause of bad breath and dental disease. Flossing is an effective way to remove plaque, soft scale, and food debris from the teeth and roots, as it can easily enter the gaps and bring out the inclusions and dirt. Floss at least once a day, especially after dinner. 4. Use a flosser: You can flush to any part of the mouth without any obstacle, including the crevices and deep gums that are not easily reached by toothbrushes, flossers and toothpicks. Use a flosser for 1-3 minutes after brushing your teeth every day to get rid of food debris in between your teeth and massage your gums at the same time. Generally, it is fine to use water for the flosser, but you can also add mouthwash or analgesic and anti-inflammatory medicine to strengthen some effects in a targeted way. 5. Scaling: In case of high calculus or gingivitis or periodontitis, supragingival scaling or subgingival scaling should be performed under the advice of the doctor to completely remove calculus. 6. Regular periodontal maintenance: Generally, periodontal tissue maintenance treatment should be performed once every 3 months of orthodontic treatment, or periodontal tissue maintenance can be performed regularly according to the doctor’s recommendation.