Our teeth are like the roots of a tree buried deep in the earth, and the roots grow in the alveolar bone. Under normal circumstances, teeth can be slightly loose within one millimeter, which is a physiological movement and has a protective effect on the teeth. Tooth loosening during the replacement of baby teeth is also normal and usually does not require treatment. Abnormal tooth loosening is mainly caused by periodontitis. Inflammation around the roots of the teeth leads to redness and swelling of the gums, resorption of the alveolar bone and gum recession, which results in a series of symptoms such as loosening of the teeth, widening of the gaps and food impaction. In addition, the impact of trauma to the teeth or the bite of hard objects can damage the elastic fibers around the roots of the teeth, which can loosen or even displace the teeth. The bite force of individual teeth is too large or there are bad habits of night grinding and clenching teeth, and long-term wrong bite will also cause loose teeth. If the inflammation of the dental pulp (dental nerve) extends to the peripheral tissues of the tooth roots and causes inflammation, it will also make the tooth loose, in which case the inflammation of the dental pulp and periapical tissues should be treated first. However, simple aging of the human body will not cause loose teeth, and the common saying “old teeth” is a long-standing misconception. In order to treat loose teeth, the cause of the loose teeth should be identified first, so that targeted treatment can be carried out. Loose teeth caused by periodontitis should be seen as soon as possible and require professional periodontal treatment. The basic treatment methods are scaling, subgingival scraping and root planing to remove plaque and tartar from the crown and root surfaces to reduce the inflammation around the teeth and slow down the resorption of the alveolar bone, and these treatments take 3-5 times to complete. After basic periodontal treatment, the lower front teeth that are significantly loose can be bonded and fixed together to increase the stability and retention time of the teeth. Since periodontitis is a recurring and irreversible disease, treatment is not a once-and-for-all procedure and requires review and retreatment every 3-6 months. If the inflammation does not subside over time, periodontal surgery will be performed at the doctor’s discretion to control the inflammation. If the tooth is heavily loosened and the surrounding inflammation is extensive, reluctant retention may cause the inflammation to spread to the neighboring teeth, resulting in loosening of the neighboring teeth, so the excessively loosened tooth needs to be extracted before full periodontal treatment. Loose teeth caused by trauma should not be ignored, and the earlier the treatment, the better the results, so as not to delay the disease. Loose teeth caused by occlusal problems should be diagnosed by an oral surgeon. If there is periodontitis, periodontal treatment should be carried out first, and then a small amount of teeth should be regraded several times to restore the correct bite relationship, and patients with night grinding should wear jaw pads to reduce the damage to the teeth. Tooth loosening caused by periapical inflammation should be treated first. After root canal treatment (nerve killing), tooth loosening will be relieved as the periapical inflammation subsides.