Dry socket, also known as limited alveolar osteomyelitis, occurs after tooth extraction and usually has no obvious precursors. After wisdom tooth extraction, there may be obvious pain at the extraction site, which cannot be relieved by general pain relief methods, or a cavity is formed at the extraction site, accompanied by bad breath, which is caused by acute bacterial infection, and at this time, it is mostly in the process of development of dry socket, which can be considered as a precursor of dry socket: 1. Pain: Under normal circumstances, pain can also appear after tooth extraction, and gradually reduce or disappear within 2-3 days. If severe pain occurs 2-3 days after tooth extraction, which can spread radiating in all directions and can radiate to the top of the head, jaw or ear-temporal area, and cannot be relieved by general pain relief methods such as ice or oral painkillers, it is generally indicative of the occurrence of dry socket; 2. Hollow: normally removing wisdom teeth will cause bleeding in the alveolar sockets, and blood clots can be formed locally after using cotton balls to compress and stop bleeding, and dry socket may occur in wisdom teeth The extraction position is empty, the blood clot disappears, or there is corruption and denaturation of the blood clot in the form of gray-white, showing cavity; 3, bad breath: local bacterial infection, blood clot or other tissue corruption and denaturation, and then mixed with food residues fermentation, the necrotic material covering the alveolar sockets can have a distinct odor, resulting in bad breath symptoms; 4, other: after the occurrence of dry socket, the patient’s jaw face is generally not significantly swollen, open mouth movement is not restricted, and some can be palpable. Part of the swollen submandibular lymph nodes can be palpated, and pressure is painful. The occurrence of dry socket is related to local trauma and bacterial infection, so pay attention to care after tooth extraction can effectively prevent dry socket, don’t touch the extraction wound with your hands, don’t eat spicy and stimulating food, pay attention to rinse your mouth after meals, avoid damaging the extraction wound when brushing your teeth, and keep your mouth clean.