Loose teeth can be caused by dental trauma, periodontitis, apical periodontitis and so on. 1. Dental trauma: dental trauma can be caused by the direct action of external forces, such as biting into hard objects when chewing, falling and hitting the teeth, etc., resulting in damage to the patient’s teeth, which leads to the loosening of the teeth. 2. Periodontitis: this disease is caused by plaque biofilm of periodontal tissues of chronic infectious diseases, plaque, trauma, systemic susceptibility factors, alveolar bone resorption, resulting in patients with loose teeth, some patients will have bleeding, pus and other symptoms. 3. Apical periodontitis: when the patient by bacterial infection, physical factors and chemical stimulation, resulting in tissue damage, inflammation, resulting in patients with loose teeth, accompanied by pain, discomfort in chewing, some patients have the appearance of pus. It is recommended that patients go to the clinic in time, under the diagnosis of the doctor, according to the development of the patient’s specific condition, to take targeted treatment.