Loose teeth in 30s may be caused by periodontitis, retrograde pulpitis, apical periodontitis and so on. 1. Periodontitis: Periodontitis when the periodontal tissues are damaged to form periodontal pockets, resulting in loss of attachment; in addition, periodontitis when the alveolar bone will be resorbed, resorption reaches the root length of up to 1/2 or more of the position of the root, there will be a crown-root disproportion, which will lead to loosening of the teeth. 2. Retrograde pulpitis: Retrograde pulpitis is mainly caused by periodontal disease, which results in loose teeth and alveolar bone resorption. 3. Apical periodontitis: In acute attacks of apical periodontitis, inflammation seeps out from the root tip, leading to loose teeth. Loose teeth in the 30s to the hospital in a timely manner, after the cause of the disease is clear and active treatment, so as not to lead to tooth loss and other adverse consequences.