Loose teeth at the age of 40 may be caused by periodontitis or jaw trauma and other diseases, the treatment methods are periodontal treatment and elimination of factors causing jaw trauma, as follows. 1. Periodontitis: periodontitis causes alveolar bone resorption, which will result in loose teeth. Through perfect periodontal treatment, including supragingival cleaning, subgingival scraping and root planing, periodontal bone grafting or implantation of bone substitutes, etc., in order to terminate the inflammation, repair the bone defects, and alleviate the loosening of teeth. 2. Jaw trauma: mostly occurring in individual teeth, treatment includes correcting bad habits such as night grinding and clenching, adjusting early contact, cuspal interference, excessive restorations, excessive orthodontic force, etc., and tooth stabilization can be restored to some extent. There may be other reasons for loose teeth at the age of 40, it is recommended to visit the hospital in time to clarify the cause of the disease and then targeted treatment.