1. anesthesia

Usually, inferior alveolar nerve, lingual nerve and long buccal nerve are selected for one-time block anesthesia. In order to reduce bleeding, ensure clear surgical field and convenient operation, anesthetics containing vasoconstrictor (epinephrine) can be infiltrated and injected into the buccal and distal sides of impacted teeth.

cut

Generally speaking, there is no need to cut the high position, or only cut away from the distant gums; It is best to choose pocket flap incision or triangular flap incision for middle and low obstruction. If the impacted teeth are deeply buried, triangular flap incision can also be used.

Mandibular impacted third molars have mandibular vascular branches on the lingual side of the posterior cushion area of distal molars, which usually do not cross the midline. The lingual nerve is located under the lingual mucosa of impacted teeth. If the distal incision is on the lingual side, it may cut off the blood vessels, resulting in more bleeding during the operation, and may also damage the lingual nerve. Therefore, the distal surgical incision must be on the buccal side, which is basically the extension of the buccal gingival sulcus incision of the second molar. In the case of local infection, the blind bag should be thoroughly washed, and the operating area should be further washed after incision.

Flip flip cover

Rotate the gingival papilla from the front end of the incision and push it back along the surface of alveolar ridge to ensure the complete separation of tissue flap. If the incision is not completely difficult to separate, it should be cut again to avoid tissue tearing caused by forced peeling. In principle, the scope can be exposed to the operating area, the buccal side does not exceed the external oblique ridge, and the lingual side does not cross the alveolar ridge.

The larger the flap, the more serious the swelling and bleeding after operation. Therefore, the range of flap turnover should be appropriate, which can not only ensure sufficient visual field, but also not affect the operation. The incision length should be such that the buccal and distal bone surfaces of the affected teeth can be properly exposed after flap turnover. For beginners, the skin flap design should be slightly larger to avoid excessive injury caused by unskilled technology or insufficient vision to extract the affected teeth.

bone

Remove all occlusal surfaces and part of buccal and distal alveolar bone. General principles: maximum circumference of exposed crown; Try to keep the height of buccal cortical bone; Determine the amount of bone removal according to the difficulty of tooth extraction and the way of crown cutting. In order to maintain the height of alveolar bone, only the part close to the affected tooth can be polished during buccal and distal bone removal. In order to protect the lingual nerve, the second molar and its periodontal bone, in principle, the lingual and mesial alveolar bone are not removed, and the distal part does not exceed the midline. The separator should be placed around the distal bone plate for protection.

When removing bone, the minimum amount of bone should be determined first. Usually, the removal of vertical impacted bone or the increase of gap must reach below the high point of crown shape. Horizontal and mesiodistal impaction should reach below mesiodistal buccal sulcus for crown cutting. Distal impaction is below the distal tooth neck to eliminate distal resistance.

Widen the gap

Grooves are ground on the buccal and distal bone walls of the affected teeth, and the grinded grooves are used as the fulcrum of the tooth puller. The width of the groove is about 2mm. When the gap is enlarged, the drill is parallel to the long axis of the tooth, and a small groove is debonded on the surface of the affected tooth. Grind the bone on the buccal and/or distal surface of the affected tooth from the small groove to separate the affected tooth from the bone wall. The depth of the groove is below the dental neck (usually equivalent to the length of the cutting drill, which will not affect the mechanical strength of the jaw), so be careful not to damage the inferior alveolar nerve canal.

Step 6 cut the affected teeth

Includes crown cutting and root splitting. Its purpose is to reduce the resistance of adjacent teeth and root bone. The common method is to cut the teeth from the center of the buccal crown to the lingual side below the root bifurcation, and divide the teeth into proximal and distal parts (in order to protect the lingual soft tissue and lingual nerve, it is usually only necessary to cut a small part of the remaining teeth lingual side). When there are still adjacent teeth in the proximal part, a transverse incision can be made at the cementum boundary of the proximal part, which is divided into two parts, crown and root, and taken out in turn. Multi-teeth can divide the root into single roots and then protrude outward respectively.

7. Pull out the affected teeth

After the resistance of adjacent teeth is completely relieved, and the bone resistance is basically relieved, select the appropriate dental tappet, and pull out the loose part with tweezers. Avoid violence, pay attention to protect adjacent teeth and bone tissue, so as not to cause damage to lingual bone plate, adjacent second molar and mandible or displacement of affected teeth. The extracted tooth tissue should be spliced and its integrity should be checked. If there are big defects, carefully check the extraction socket to avoid falling.

Treatment of tooth extraction socket

Use physiological saline to clean the extraction socket and/or use strong suction to thoroughly clean the debris. Scraper can be used to scrape off the debris attached to soft tissue, but it is not allowed to scratch the alveolar fossa excessively, so as not to affect the healing. For granulation tissue, if fragile, soft and bleeding inflammatory granulation tissue is found, it should be scraped off; If it is tough and dense fibrous connective tissue, it is beneficial to healing and does not need to be scraped off. The dental capsule around the crown should be removed to avoid the formation of residual cysts. Compress and shrink the enlarged alveolar fossa, trim the sharp bone margin and take out the free bone fragments. In order to prevent bleeding, 1 ~ 2 pieces of colloidal sponge can be placed in the extraction socket.

suture

Don't sew too tightly. Usually, the distal end of the second molar can be sutured, which can not only achieve the purpose of suture, but also drain the bleeding and reaction products in the wound, thus reducing the postoperative swelling and hematoma formation. When suturing, the anatomical landmark points of tissue flap, such as the cutting angle of incision and gingival papilla, should be sutured first to avoid the displacement of tissue flap during suturing. After the suture is completed, cover the tooth extraction wound with a sterile cotton roll, and ask the patient to bite tightly and pressurize to stop bleeding.

Postoperative doctor's advice: same as general tooth extraction. Antibiotics and painkillers can be used appropriately after mandibular impacted teeth are extracted.