The indications for subgingival scaling are mainly gingivitis, periodontitis, removal of subgingival calculus and plaque through scaling instruments. 1. Gingivitis: The best treatment for gingivitis is to perform supragingival scaling first, and if there are more stones under the gingiva, then with the subgingival scaling to remove the stones and plaque attached under the gingiva, so as to reduce the inflammation of the gums. 2. Periodontitis: In periodontitis, there is more plaque under the gingiva, and there is often a loss of attachment, which requires subgingival scaling and root planing, which can make the teeth form new attachments. Whether it is gingivitis or periodontitis, oral hygiene should be checked regularly after surgery, usually every three to six months. Subgingival scraping is easy to bleed, it is best to choose to go to a regular hospital, you can avoid some infectious diseases.