If the second molar can be treated and preserved, root canal treatment is recommended, and if it cannot be preserved, extraction is recommended. 1. The second molar is not a wisdom tooth, it is a large tooth that performs the function of chewing in the normal dentition, so it should be preserved as much as possible. If pulpitis or periapical periodontitis is present, then root canal treatment is recommended to preserve the tooth. 2. If the second molar has a large area of missing teeth, or even stumps, or if there is severe periodontitis and the tooth is obviously loose, it is recommended to be extracted if it cannot be retained. Generally, restorative treatment will be recommended after extraction. Second molar root canal or extraction is recommended to regular hospitals, listen to the advice of a professional doctor.