JAW SURGERY TECHNIQUES
Maxilla & Mandible Osteotomy (Upper & Lower Jaw)
Maxilla Osteotomy (Upper Jaw)
This procedure is intended for patients with an upper jaw deformity, or with an open bite. Operating on the upper jaw requires surgeons to make incisions below both eye sockets, making it a bilateral osteotomy, enabling the whole upper jaw, along with the roof of the mouth and upper teeth, to move as one unit. At this time, the upper jaw can be moved and aligned correctly in order to fit the upper teeth in place with the lower teeth. Then, the jaw is stabilized using titanium screws that will eventually be grown over by bone, permanently staying in the mouth.
Mandible Osteotomy (Lower Jaw)
The mandible osteotomy is intended for those with a receded mandible (lower jaw) or an open bite, which may cause difficulty chewing and jaw pain. For this procedure cuts are made behind the molars, in between the first and second molars, and lengthwise, detaching the front of the jaw so the palate (including the teeth and all) can move as one unit. From here, the surgeon can smoothly slide the mandible into its new position. Stabilization screws are used to support the jaw until the healing process is done.
Sagittal Split Osteotomy
Sagittal Split Osteotomy
This procedure is used to correct mandible retrusion and mandibular prognathism (over and under bite). First, a horizontal cut is made on the inner side of the ramus mandibulae, extending anterally to the anterior portion of the ascending ramus. The cut is then made inferiorly on the ascending ramus to the descending ramus, extending to the lateral border of the mandible in the area between the first and second molar. At this time, a vertical cut is made extending inferior to the body of the mandible, to the inferior border of the mandible. All cuts are made into the middle of the bone, where bone marrow is present. Then, a chisel is inserted into the pre existing cuts and tapped gently in all areas to split the mandible of the left and right side. From here, the mandible can be moved either forwards or backwards. If sliding backwards, the distal segment must be trimmed to provide room in order to slide the mandible backwards. Lastly, the jaw is stabilized using stabilizing screws that are inserted extra-orally. The jaw is then wired shut for approximately 4–5 weeks.
Genioplasty Osteotomy (Intra-oral)
This procedure is used for the advancement (movement forward) or retraction (movement backwards) of the chin. First, incisions are made from the first bicuspid to the first bicuspid, exposing the mandible. Then, soft tissue of the mandible is detached from the bone; done by stripping attaching tissues. A horizontal incision is then made inferior to the first bicuspids, bilaterally, where bone cuts (osteotomies) are made vertically inferior, extending to the inferior border of the mandible, thereby detaching the bony segments of the mandible. The bony segments are stabilized with titanium plates; no fixation (binding of the jaw) necessary. If advancement is indicated for the chin, there are inert products available to implant onto the mandible, utilizing titanium screws, bypassing bone cuts.
Rapid Palatal Expansion Osteotomy
When a patient has a constricted (oval shape) maxilla, but normal mandible, many orthodontists request a rapid palatal expansion. This consists of the surgeon making horizontal cuts on the lateral board of the maxilla, extending anterally to the inferior border of the nasal cavity. At this time, a chisel designed for the nasal septum is utilized to detach the maxilla from the cranial base. Then, a pterygoid chisel, which is a curved chisel, is used on the left and right side of the maxilla to detach the pterygoid palates. Care must be taken as to not injure the inferior palatine artery. Prior to the procedure, the orthodontist has an orthopedic appliance attached to the maxilla teeth, bilaterally, extending over the palate with an attachment so the surgeon may use a hex-like screw to place into the device to push from anterior to posterior to start spreading the bony segments. The expansion of the maxilla may take up to 8 weeks with the surgeon advancing the expander hex lock, sideways (← →), once a week.