Periodontitis is a destructive inflammatory condition of the periodontal supporting tissues. The primary initiating factor of periodontitis is dental plaque, which occurs due to not brushing or rinsing promptly after eating. Over time, soft deposits accumulate around the teeth, which can calcify into tartar. The tartar contains a large amount of biofilm, such as the dental plaque biofilm, which can damage and cause bleeding or congestion in the gingival tissues, manifesting as bleeding when brushing teeth or eating. If gingivitis is not treated in time, it may lead to periodontitis. Periodontitis is also related to other systemic factors, such as genetic factors or smoking, mental stress, etc. Sometimes, discoloration of the tooth surfaces or food impaction can also cause periodontitis.