Dental bed is also known as the gums, leaning back the gums swollen and painful may be wisdom teeth pericoronitis, periapical periodontitis or herpes and other oral mucosal diseases, need to be rinsed, root canal or drug treatment. 1. Wisdom tooth pericoronitis: swollen gums against the back of the gums may be wisdom tooth obstruction, causing localized swelling and pain in the gums, the treatment requires the use of saline and hydrogen peroxide alternately rinse deepened gingival pockets, and then the use of iodine povine topical medication, and then consider the removal of wisdom teeth. 2. Periapical inflammation: When the tooth is periapical inflammation, the inflammation will penetrate the periosteum to reach the gingiva, causing swelling and pain in the mucous membrane, and root canal treatment is needed to establish a pulpal pathway and eliminate periapical inflammation. 3. Herpes: Herpes virus infection causes herpes to appear on the oral mucosa, with clusters of small blisters on the gums, followed by erosion. Treatment with antiviral drugs acyclovir, or local gargle chlorhexidine. Swelling and pain in the posterior dental bed is recommended to consult a doctor to check the cause of the disease in a timely manner, and the use of medication should be in accordance with the doctor’s instructions.