Post-extraction bleeding Primary bleeding is bleeding that does not stop at the time of extraction; secondary bleeding is bleeding that has stopped at the time of extraction but occurs later due to other reasons. General bleeding is common after tooth extraction, but major bleeding is less common. For example, gum tissue tear, extraction of more than 3 teeth at a time, alveolar bone damage and pericoronitis, foreign body left in the socket, periodontitis, improper diet and rinsing, and periapical inflammation. Post-extraction bleeding mostly occurs within 24 hours after surgery, and the bleeding site is most frequent in the molars. Cheek swelling Cheek swelling often occurs after wisdom tooth extraction and starts 12-24 hours after surgery and gradually decreases within 3-5 days. The swollen area is soft and elastic, and the skin can be pinched up, mainly due to the exudation of traumatized tissue and obstruction of lymphatic return. Infection The main symptoms of post-extraction infection are restricted mouth opening and painful swallowing, localized redness, swelling and pressure pain. The causes are mainly due to the lack of careful preoperative disinfection, too much tooth extraction trauma, improper treatment of dental trauma, and systemic conditions. Dry socket syndrome Dry socket syndrome usually appears 2-3 days after tooth extraction and is characterized by the decomposition and loss of academic clots in the alveolar sockets, empty sockets, exposed bone walls, bad breath and severe pain radiating to the top of the head. Although the oral cavity is a contaminated environment, the infection is preventable because of the rich blood supply and anti-inflammatory capacity of the maxillofacial region. Tooth extraction during inflammatory periods may lead to the spread of inflammation, so try not to extract teeth during inflammatory periods.