Technique Orthognathic surgery

1 technique

1.1 maxilla osteotomy (upper jaw)
1.2 mandible osteotomy (lower jaw)
1.3 sagittal split osteotomy
1.4 genioplasty osteotomy (intra-oral)
1.5 rapid palatal expansion osteotomy

technique

all dentofacial osteotomies performed under general anesthesia, causing total unconsciousness. general anesthesia allows surgeons perform dentofacial osteotomies without involuntary muscle movement or complaints minor pain. prior osteotomy, third molars (wisdom teeth) extracted reduce chance of infection. dentofacial osteotomy performed using oscillating , reciprocating saws, burs, , manual chisels. reciprocating saws straight , used making straight bone cuts. oscillating saws angled, different degrees, in order make deep curved cuts osteotomies mandible angle reduction. recent advent of piezoelectric saws has simplified bone cutting, such equipment has not yet become norm outside of developed countries. surgery might involve 1 jaw or both jaws cuncurrently. modification done making cuts in bones of mandible and/or maxilla, , repositioning cut pieces in desired alignment. surgery performed use of general anaesthetic , nasal tube intubation. nasal tube enables teeth wired during surgery. surgery not involve cutting skin. instead, surgeon able go through interior of mouth. cutting 1 bone known osteotomy, while performing surgery on both jaws simultaneously known bi-maxillary osteotomy (cutting bone of both jaws) or maxillomandibular advancement.

the maxilla can adjusted using lefort level osteotomy (most common). additionally, midface can mobilized using lefort ii, or lefort iii osteotomy. these techniques utilized extensively children suffer various craniofacial abnormalities, such crouzon syndrome.

the jaws wired (inter-maxillary fixation) using stainless steel wires during surgery ensure correct re-positioning of bones. in cases, these wires released before patient wakes up. however, surgeons prefer wire jaws shut instead.

in instances, change in jaw structure cause cheeks become depressed , shallow. procedures call insertion of implants give patient s face fuller look.

alveolar prognathism, maxillary osteotomy recommended.


maxilla osteotomy (upper jaw)

this procedure intended patients upper jaw deformity, or open bite. operating on upper jaw requires surgeons make incisions below both eye sockets, making bilateral osteotomy, enabling whole upper jaw, along roof of mouth , upper teeth, move 1 unit. @ time, upper jaw can moved , aligned correctly in order fit upper teeth in place lower teeth. then, jaw stabilized using titanium screws grown on bone, permanently staying in mouth.

mandible osteotomy (lower jaw)

patient exhibits mandible prognathism. requires mandible osteotomy correct.

the mandible osteotomy intended receded mandible (lower jaw) or open bite, may cause difficulty chewing , jaw pain. procedure cuts made behind molars, in between first , second molars, , lengthwise, detaching front of jaw palate (including teeth , all) can move 1 unit. here, surgeon can smoothly slide mandible new position. stabilization screws used support jaw until healing process done.

sagittal split osteotomy

oral palate unit.

this procedure used correct mandible retrusion , mandibular prognathism (over , under bite). first, horizontal cut made on inner side of ramus mandibulae, extending anterally anterior portion of ascending ramus. cut made inferiorly on ascending ramus descending ramus, extending lateral border of mandible in area between first , second molar. @ time, vertical cut made extending inferior body of mandible, inferior border of mandible. cuts made middle of bone, bone marrow present. then, chisel inserted pre existing cuts , tapped gently in areas split mandible of left , right side. here, mandible can moved either forwards or backwards. if sliding backwards, distal segment must trimmed provide room in order slide mandible backwards. lastly, jaw stabilized using stabilizing screws inserted extra-orally. jaw wired shut approximately 4–5 weeks.

facial anatomy.


genioplasty osteotomy (intra-oral)

this procedure used advancement (movement forward) or retraction (movement backwards) of chin. first, incisions made first bicuspid first bicuspid, exposing mandible. then, soft tissue of mandible detached bone; done stripping attaching tissues. horizontal incision made inferior first bicuspids, bilaterally, bone cuts (osteotomies) made vertically inferior, extending inferior border of mandible, thereby detaching bony segments of mandible. bony segments stabilized titanium plates; no fixation (binding of jaw) necessary. if advancement indicated chin, there inert products available implant onto mandible, utilizing titanium screws, bypassing bone cuts.

rapid palatal expansion osteotomy

when patient has constricted (oval shape) maxilla, normal mandible, many orthodontists request rapid palatal expansion.

this consists of surgeon making horizontal cuts on lateral board of maxilla, extending anterally inferior border of nasal cavity. @ time, chisel designed nasal septum utilized detach maxilla cranial base. then, pterygoid chisel, curved chisel, used on left , right side of maxilla detach pterygoid palates. care must taken not injure inferior palatine artery. prior procedure, orthodontist has orthopedic appliance attached maxilla teeth, bilaterally, extending on palate attachment surgeon may use hex-like screw place device push anterior posterior start spreading bony segments. expansion of maxilla may take 8 weeks surgeon advancing expander hex lock, sideways (← →), once week.