The chin has a more pronounced effect on the contour of the lower 1/3 of the face. The importance of local abnormalities on the aesthetic appearance has been emphasized. The coordinated structure of the face should be differentiated into upper, middle and lower third, and the lower third of the face is divided into upper, middle and lower third for the upper, lower lip and chin section to determine whether the morphological position of the chin is appropriate. In this way, the direction and distance of movement of the chin bone segment for chinplasty is established and the surgical plan is formulated. Commonly used chinoplasties include chin advancement, chin retraction, chin augmentation, chin reduction (also called chin lengthening), and chin deviation correction. By using the intraoral route, there is no scar on the face after surgery and the cosmetic effect is good. The surgery can be performed under local anesthesia or general anesthesia. I. Chin lengthening surgery Surgical methods: ① Incision and stripping: from the first premolar of the mandible on one side to the first premolar on the opposite side about 10 mm above the bottom of the vestibular groove of the labial mucosa incision, incision of the mucosa, part of the chin muscle, straight to the periosteum. The periosteum was dissected and peeled under the periosteum, and the mucoperiosteal flap was lifted to reveal the chin vascular nerve bundle at the chin nerve foramen below the apices of the proximal lateral molars for protection. The periosteum of the median mandibular joint is dissected (but the periosteal attachment below the line of osteotomy can also be preserved) to the posterior aspect of the mandibular margin. After stripping, the lower lip can be pulled downward to dislodge the chin bone from the incision. ②Osteotomy: According to the design plan, a line is made at the submandibular margin below the chin hole and 1~1.5cm from the subchin margin of the chin median for those who simply have a receding chin, which is the osteotomy line for chin advancement. Osteotomy is performed with a pendulum saw or cleft drill. In order to maintain symmetry, an alignment line perpendicular to the plane should be made in the midline and under the apices of the cuspids on both sides for partial bone removal for chin hypertrophy as follows, and the bone should be cut at 4-5 mm below the apices as far as possible so that the lower bone section has more periosteal and soft tissue attachment. The oscillating saw or high-speed dental drill is used to make the lower osteotomy first, and then the upper osteotomy incision is made, and the wedge-shaped bone block can be removed after the lower bone segment is loosened. If the chin is simply longer, the long part can be directly ground out. ③Fixation: either steel wire or miniature steel piece can be used. The incision is sutured and wrapped with pressure. (Figure 1-8). Second, the chin filler is suitable for small chin deformity, and unwilling to perform osteotomy forward, the advantage of which is that the operation is simple and can increase the long protrusion of the chin protrusion and the height of the chin protrusion and the width of both sides at will. The filling materials used are autologous bone, artificial bone, polytetrafluoroethylene expanded (Gore-Tex) silicone blocks and high-density polyethylene (Medpor. HDPE). Procedure: 1. The height and width of the proposed filling is measured on a frontal and lateral radiograph. The size and shape of the filling can also be precisely measured by simulating the shape with a plaster. Disinfection will be used for intraoperative reference. 2. Mark the anterior margin of the chin in the median line of the chin and accurately mark the filling area on both sides with Merlot. An incision of about 3-4 cm in length was made on the gingival side of the mandibular vestibular sulcus 1.5 cm from the bottom of the sulcus to reach the subperiosteum, and the filling cavity was peeled out with a periosteal stripper according to the marked area. When stripping, note that the lower edge of the jaw should be about 1cm toward the posterior edge of the jaw, and the lip side will show excessive protrusion after filling. 3. Implantation of filling material: The shaped bone block or other graft material will be marked with US blue in the midline so that the midline of the implant can be observed to be consistent with the midline of the chin after implantation. The assistant pulls up one side of the implant cavity with a right-angle pull hook and inserts the implant into the end of the cavity while pulling open the other side of the cavity to incorporate the implant. 4. Fixation: If it is hard implant material, it is fixed with steel wire or 3/0 nylon thread after drilling holes. If the wheel quality material can be fixed by connecting sutures on the membrane membrane 2 to 3 stitches. Before fixation, make sure to check the parallel direction of the median line and the mandibular rim as well as the front and back of the chin to make sure there is no displacement and tilt in the left and right direction, horizontal direction, front and back direction before fixation. 5. After the layered suture, use two 2cm wide and 8-10cm long adhesive tapes, one from the lower lip to both sides of the mandibular edge around to the bottom of the jaw, and the other to the bottom of the chin to grab the chin chin around to the front edge of the jaw. The chin reduction surgery is suitable for patients with excessive protrusion of the chin. The osteotomy line and range are designed on the x-ray before surgery. Surgical method ① Incision stripping is the same as chin lengthening surgery. The operation can be completed under local anesthesia. ② After dissection, the chin bone is removed from the incision and the osteotomy line and the extent of partial removal of the chin bone are precisely marked according to the preoperative design of the osteotomy range. The highest point of the osteotomy line should be located below 5mm below the tip of the root of the lower teeth. (③) Osteotomy retraction