The causes of loose teeth include apical periodontitis, periodontitis, and object impact, etc. They can be treated with root canal treatment, splinting, and wearing a dental retainer depending on the cause. 1. Apical periodontitis: When a tooth has apical periodontitis, inflammatory substances will break through the periosteum and alveolar bone, thus stimulating the alveolar and periodontal membranes and making the tooth loose. In this case, it is recommended to use root canal treatment to eliminate the inflammatory substances in the apical part of the root to avoid further development of the disease. 2. Periodontitis: Periodontitis can lead to gum contraction and alveolar bone resorption, which in turn leads to loose teeth. In the face of this problem, you can use a small splint to fix the loose teeth and the surrounding stable teeth together, which can reduce the burden on the teeth and play the effect of fixing the teeth. 3. Object impact: When hit by an object, the periodontal membrane may be damaged, resulting in loose teeth. Usually, you can wear a dental retainer for treatment, and after the periodontal membrane heals, the loosening symptoms will gradually disappear. Loose teeth can affect chewing and eating, so you should consult a doctor at the beginning of the symptoms to receive timely treatment, and after the doctor examines the cause of the loosening, he or she will formulate a specific treatment plan to treat or fix the teeth.