Subgingival scaling is a common method of removing subgingival tartar, and some people may experience adverse reactions such as pain, bleeding gums, sensitivity, periodontal abscesses, and increased tooth looseness during or after the procedure. 1. Pain: The instruments used in subgingival scaling are sharp and may cause a certain degree of pain and discomfort when touching the gums in the inflammatory stage. It can be operated under local anesthesia to reduce the pain. 2. Bleeding gums: When the gums are in the inflammatory state of congestion and edema, there may be a small amount of bleeding when touched by sharp instruments, which can be relieved on its own. For people with high blood pressure, blood system diseases, menstruation and other special groups, should be evaluated by a specialist before performing subgingival curettage, in order to reduce postoperative bleeding. 3. Root surface sensitivity: after subgingival scaling, there may be exposure of dentin, which may show different degrees of sensitivity after encountering hot and cold stimuli. Generally, it can be relieved by itself, and desensitization treatment is feasible for those with heavy sensitivity. 4. Periodontal abscess: mainly due to a small amount of tartar residue or tartar is pushed into the deep tissues, there may be biting discomfort or pain, tooth loosening aggravated, periodontal pockets overflowing pus and other symptoms. It is necessary to consult a doctor in time and pay attention to the maintenance of oral hygiene on weekdays. 5. Increased tooth looseness: After removing tartar by subgingival scraping, the teeth lose the role of tartar “temporary support”, and the degree of looseness can be increased. In addition, due to postoperative periodontal membrane congestion and edema, changes in female hormone levels, etc., can lead to increased tooth looseness. This usually resolves on its own after a period of time after surgery. If any of the above situations occurs, it is necessary to consult a doctor for appropriate treatment.