I. Purpose of surgery 1. To remove the diseased tissue from the periodontal pocket wall, expose the diseased root surface and alveolar bone, and facilitate the thorough removal of plaque, tartar and diseased tissue from the root surface under direct vision. 2.To make the periodontal pockets shallow or return to normal, so that patients and practitioners can easily keep the tooth surface clean and reduce the recurrence of inflammation. Liang Zhaozhong, Special Oral Clinic, Urumqi Stomatological Hospital 3.Correct the soft and hard tissue defects and bad shape caused by periodontal lesions, establish physiological gingival shape, facilitate patients’ own control of plaque and maintain oral hygiene. 4.Promote periodontal tissue repair and regeneration, and establish new periodontal attachment relationship. 5, restore the aesthetic and functional needs as well as facilitate the restoration of teeth or dental series, such as covering the exposed root surface, widening the attached gingiva, changing the position of the tethered attachment, extending the l clinical crown, dental implants, etc. Second, the timing of surgery whether the patient needs periodontal surgery treatment, should be at least 1 to 3 months after the periodontal basic treatment, a comprehensive periodontal examination and the necessary X-ray review to make a judgment and the choice of surgical methods. The basic treatment should include oral hygiene instruction, extraction of the affected teeth that cannot be retained, supragingival scaling, subgingival scraping (root surface leveling), necessary occlusal adjustment after inflammation control, and also elimination of all plaque retention factors and necessary endodontic treatment. The review should be done to understand the patient’s response to the basic treatment and current condition, the patient’s age and general health, whether the patient can cooperate well, whether the patient can effectively control oral hygiene, and whether the smoker is willing to quit smoking. Only after the completion of treatment and comprehensive review can surgery be performed on those who meet the indications. Third, the indications for surgery After the basic treatment, the oral hygiene is good, but still has the following conditions, should consider surgical treatment. 1.After subgingival scraping, the periodontal pocket is still ≥5mm, and there is bleeding or pus overflow after probing. 2, Those whose root surface irritants cannot be completely removed by basic treatment, commonly in the molar root bifurcation area and premolar area. 3.Irregular alveolar bone shape, deep pit-like resorption, bone sub-pockets, etc., must be surgically revised bone shape, or bone grafting, or guided tissue regeneration. 4, the root division of the posterior teeth and lesions up to degree II or III, surgery is conducive to thorough scraping of tartar and plaque, exposure of root division, or guided tissue regeneration to repair the bone at the lesion, or the need for root amputation, root division, half tooth removal, etc. 5.The distal mesial bone pocket of the last molar requires surgical treatment. 6.There are problems such as attachment gingival is too narrow, individual teeth gingival recession, etc., need to use membrane gingival surgery for treatment. 7.Decay or tooth fracture up to subgingival and affect the dental restoration, or the restoration destroys the biological width, or the anterior teeth have short clinical crowns and show too much gingival when smiling, and need surgery to extend the clinical crown for treatment, restoration, or improve the aesthetics. The appropriate surgical method should be selected according to the specific situation of the affected tooth. The soft tissue wall of the periodontal pocket, the root surface, the alveolar bone under the pocket, and the attached gingiva are several important areas for periodontal surgery. Mainly include: 1, the morphological characteristics, thickness, anatomical characteristics of the soft tissue wall of the periodontal pocket and the presence of inflammation; the depth, extent, and relationship with the alveolar bone of the periodontal pocket, i.e., the suprabony pocket or infrabony pocket (intrabony pocket); 2, the presence of root surface tartar and other irritants, the presence of root bifurcation lesions, and whether instruments can enter the lesion area; 3, the morphology and height of the alveolar bone, the presence of pit-like resorption, horizontal or vertical 4. the presence of attached gingiva of appropriate width, the thickness and shape of the gingiva, and the presence of other membrane gingival defects or aesthetic problems. 5. Attention should also be paid to the patient’s response to basic treatment, the patient’s degree of cooperation, whether plaque control and good El cavity hygiene can be maintained, whether the patient smokes and whether he can quit smoking, etc. V. Contraindications to surgery 1. Local inflammation and etiology have not been eliminated. 2, the patient can not cooperate because good plaque control is one of the decisive factors for the success of periodontal surgical treatment, if the patient does not pay attention or fails to fully grasp and implement plaque control in the basic treatment stage due to disability, etc., the surgical treatment should not be performed. Some scholars report that surgery is harmful but not beneficial to the periodontal condition of those with poor plaque control. 3. Those who suffer from systemic diseases that are not controlled (e.g., uncontrolled diabetes) or cannot undergo surgical procedures due to systemic conditions, e.g., hematologic diseases, cardiovascular accidents that have occurred within six months, etc. In addition, the postoperative healing and efficacy are poor for those who smoke a lot. Sixth, the basic points of surgery 1, preoperative preparation before surgery must be cleaned, scraping and other removal of the cause and anti-inflammatory treatment, the patient must master the method of plaque control, so that no or only a small amount of plaque on the surface of the operated area, and after surgery can adhere to the removal of plaque. The patient should be explained to the patient before the operation, so that the patient understands the purpose of periodontal surgery and the problems that may occur during and after the operation, and obtains the patient’s informed consent. Before surgery, we must understand the patient’s general health condition and whether preventive medication is needed; make necessary laboratory tests, such as blood routine, bleeding time, clotting time, screening for certain infectious diseases, etc. Detailed examination and recording of the periodontal pocket depth, attachment level, gingival margin position, attached gingival width, tooth mobility and other clinical indicators of the surgical site should also be made. 2, aseptic concept for periodontal surgery and other oral surgery requirements, there should be aseptic concept, pay attention to aseptic operation, and prevent cross infection. 3, painless surgery application of local infiltration anesthesia or nerve conduction block anesthesia, so that the surgery to achieve painlessly and smoothly, if necessary, can use sedatives. 4, reduce trauma intraoperative operation should be gentle and accurate, try to avoid damage to periodontal tissues, for example, avoid excessive pressure on soft tissues when turning mucoperiosteal flap, avoid tearing of gingival flap; in order to maintain clear intraoperative vision, intraoperative use of suction instead of dry gauze wipe, avoid cotton fiber to stay in the wound; avoid unnecessary long time exposure and damage of alveolar bone, keep the bone moist; intraoperative rinse with sterile saline during intraoperative rinsing; ensure that the soft tissue will completely cover the bone surface when suturing, etc. 5.Suturing In most periodontal surgeries, the gingival flap needs to be sutured to fix the gingival flap in the desired position, and the gingival flap should completely cover the bone surface and fit with the bone and tooth surface. 6, periodontal plugging agent (protective agent) application of periodontal surgery is often placed on the surface of the wound in the operative area, can avoid chewing food, tongue and other contact with the wound to prevent trauma to the operative area. The plugging agent has the functions of hemostasis, pain relief, wound protection, infection prevention and soft tissue fixation. Its composition and application are described in section III of this chapter. 7. Postoperative care ①Patients should be informed of possible pain reactions after surgery and given analgesics as a backup. ②Postoperative plaque control is the most important factor for the success of surgery, postoperative short-term pain and discomfort often affect the maintenance of self-oral hygiene, patients can be allowed to use antimicrobial rinses, such as 0, 12% to 0, 2% chlorhexidine gargle, twice a day, each gargle for l minutes, and after the removal of stitches still have to allow patients to review the cleaning of the dental surface, which is an effective method of mechanical plaque removal within one month after surgery. ③ Postoperative wound stability is another important factor affecting the postoperative outcome. In addition to using appropriate suturing techniques during surgery, the gingival tissue should be protected from mechanical ah trauma at the earliest stage of postoperative healing, such as not using the operated area to chew food, etc. Generally, the sutures should be removed 7 days after surgery. If there are special requirements for postoperative wound stability, the suture removal time can be delayed or the treatment agent can be placed again. After the stitches are removed, the operated area can be rinsed with saline or 1% H. If the healing is satisfactory, the patient can be allowed to gently brush the teeth with a soft-bristled toothbrush and gently clean the adjacent surface with a toothpick, paying attention not to use the gap brush in the early stage to avoid damage to the adjacent tissue. At this time, the patient can be reviewed once every 2 weeks to check the plaque control, and the interval between reviews can be gradually increased. ⑤ Whether to apply antibiotics prophylactically after surgery can depend on the type of surgery, the scope of surgery and the patient’s systemic condition. Non-indications 1.Without basic treatment, periodontal inflammation is not eliminated. 2.The periodontal pocket is too deep and the bottom of the pocket exceeds the membrane gingival union. 3, Alveolar bone lesion and poor morphology, need to perform bone surgery. 4, periodontal pockets of anterior teeth, gingivectomy will lead to root exposure, affecting the aesthetics.