Eight, hyperbaric oxygen pretreatment and the application in oral diseases 1, hyperbaric oxygen pretreatment: before going to the plateau, before the skin flap transplantation, heart and brain and other surgical procedures to give hyperbaric oxygen therapy, that is, hyperbaric oxygen pretreatment. Hyperbaric oxygen pretreatment can reduce plateau reaction, or delay the occurrence of plateau reaction; hyperbaric oxygen pretreatment can significantly improve the survival rate of transplanted skin flap (up to 20%;); hyperbaric oxygen pretreatment has a protective effect on the ischemia-reperfusion injury of many important organs such as myocardium and brain tissue, which will effectively prevent and treat anesthesia and surgery-related damage to important organs such as heart and brain, so that patients can successfully pass the perioperative period and speed up the recovery of transplanted organs It will enable patients to pass the perioperative period smoothly, speed up the recovery of transplant organs and postoperative rehabilitation of various surgeries. Beijing Chaoyang Hospital Hyperbaric Oxygenation Department Yang Lin 2, the application of hyperbaric oxygen in stomatology: (1) Periodontal disease and periodontitis: the incidence is high, the course of the disease is long, will cause tooth loosening and tooth loss. The prevalence rate is higher than that of dental caries in China. By inhibiting the growth of anaerobic bacteria, hyperbaric oxygen promotes the repair of periodontal tissues, reduces gingival bleeding and enhances the proliferation of collagen fibers and connective tissues in the lesion area. Hyperbaric oxygen, together with endodontic treatment, can improve periodontal tissue damage significantly with an efficiency of 90%; above. (2) Radiation osteonecrosis: Hyperbaric oxygen is now recommended as the most effective conventional adjunctive treatment for radiation osteonecrosis. Radiation osteonecrosis of the jaw is commonly seen after surgery for nasopharyngeal carcinoma and seriously affects the quality of life of patients. The efficiency of hyperbaric oxygen treatment for radiation osteonecrosis is reported to be 94.4%; and the cure rate is 78.8%;. (3) Artificial dental implants: an emerging restorative technique. Clinical studies have confirmed that hyperbaric oxygen therapy after implant surgery has the effect of reducing the inflammatory reaction in the implant area, promoting new bone formation and accelerating the speed of implant bone fusion, with a clinical efficiency of up to 100%. (4) Dislocation of young permanent anterior teeth: the incidence is high in pediatric dentistry. Hyperbaric oxygen has a significant effect on preserving the living pulp of dislocated young permanent teeth, reducing root resorption and preventing loosening of reimplanted teeth. Studies have confirmed that the overall success rate of hyperbaric oxygen treatment for tooth replantation is 97.26%; while the overall success rate of tooth replantation without hyperbaric oxygen treatment is only 70.77%;.