Orthognathic surgery is used to correct skeletal discrepancies of the jaw bones that cannot be addressed by orthodontics alone. It involves both pre-surgical orthodontics to position the teeth and surgical procedures on the mandible and/or maxilla. Common mandibular procedures include sagittal split osteotomy to move the mandible forwards or backwards and vertical subsigmoid osteotomy to push the mandible back. The main maxillary procedure is a Le Fort I osteotomy where the maxilla is freed and can be repositioned using a buccal incision approach. Both procedures aim to correct functional and aesthetic issues of the jaws and require postoperative orthodontics for detailed occlusion.

1. PRESENTERS
MUGABE LAURENCE
NAKIMERA BETTY
MALE JUDE
ORTHOGNATHIC SURGERY

2. OUTLINE
 Introduction
 Indications
 Diagnosis And Treatment Planning
 Sequence Of Treatment
 Mandibular procedure
 Maxillary procedure

3. Introduction
 Orthognathism: comes from the word
orthognathia that refers to the study and causes
and treatment of conditions related to the mal-
position of bones of the jaw.
Orthognathic surgery is the correction of skeletal
discrepancies that due to their severity lie out
side the scope of orthodontics alone.

4. indications
 Indications are functional:
 Speech
 Eating
 Secondary indications are aesthetics

5. Diagnosis and treatment
planning.
 This is best done jointly by an orthodontist
and a maxillofacial surgeon and ideally with
psychology input. The following information is
required:
 Patient’s perception of problem Are they
concerned with appearance of jaws or teeth,
speech, or problems with eating? Are their
expectations realistic?
 Clinical examination Assessment of the
balance and proportions of full face and
profile.

6.  Study models Needed to assess coordination of
arches.
 Radiographs Require DPT and lateral skull, plus
PA skull for asymmetries.
 Photographs Required as pre-Rx record and can
also be manipulated with lateral skull for visual
computer predictions
 It is important to correlate desired facial changes
with the patient’s occlusion
 Pre-surgical orthodontics will be required to
decompensate teeth so that a full surgical
correction is possible.

7.  It is important (in order to obtain informed
consent) that patients are fully informed of the
risks of surgery, particularly mandibular
procedures, in addition to the orthodontic risks.

8. Sequence of Rx
 Pre-surgical orthodontics The aim of this phase is
to align and coordinate the arches so that the
teeth will not interfere when the jaws are placed
in their correct position. This usually involves
decompensation, i.e. removal of any dento-
alveolar compensation for the skeletal
discrepancy so that the teeth are at their correct
axial inclinations and a full surgical correction can
be achieved

9.  Post-surgical orthodontics Lighter round wires
and inter-maxillary traction are used to detail
occlusion.
 Retention This is the same as after conventional
FA Rx.
 Relapse This can be surgical or orthodontic, or
both.
 Relapse is more likely in Rx of deficiencies as
soft tissues are under greater tension
postoperatively

10. Mandibular procedure
 Involve ramus, body, alveolus, or chin.
 IO vertical subsigmoid osteotomy Used to push
back the mandible.
 EO approach used when suitable equipment for
IO not available.
 The IO procedure is straightforward, performed
via an extended third-molar type incision. Bone
cuts are made with a right-angled oscillating saw
from sigmoid notch to lower border. Technique is
very instrument dependent.

11. Sagittal split osteotomy
 (Fig. 12.5 and Fig. 12.6.) Can move mandible
backwards or forwards.
 IO incision similar to intra-oral vertical
subsigmoid osteotomy. Bone cuts made from
above lingula, across retromolar region, down
buccal aspect to lower border.
 Split sagittally with an osteotome followed by
spreaders.
 Main complication is paraesthesia of IDN.

13.  Inverted L- and C-shaped osteotomy Usually EO
approach. Rarely used; can lengthen ramus if used
with bone graft.
 Body ostectomy Shortens body of mandible. Need to
gain space orthodontically or remove tooth. Watch
mental nerve.
 Subapical osteotomy Used to move dento-alveolar
segments. Technically more difficult than it looks. Risk
to tooth vitality.
 Genioplasty The tip of the chin can be moved pretty
much anywhere; the secret is to keep a sliding
contact with bone and a muscle pedicle. Fixation
should be kept away from areas of muscle activity as
this leads to bone resorption. Effective treatment for
obstructive sleep apnoea.

14. Maxillary procedure
 Segmental Can be single-tooth, or bone and
tooth blocks, e.g. Wassmund procedure, which
involves tunneling incisions in buccal sulcus and
palate to move premaxilla. Problems are finding
space for bone cuts and avoiding damaging
teeth.

15.  Le Fort I Mainstay procedure. Standard
approach is the ‘down-fracture’ with horseshoe
buccal incision, bone cuts at Le Fort I level, and
segment pedicled on the palate. The freed
maxilla can be moved up, down, or forward.
 Posterior movement more problematic. In cleft
palate cases, concern over the adequacy of the
palatal blood supply has led to some surgeons
using tunnelled buccal incisions to make the
bone cuts, thus preserving some of the buccal
blood supply to the maxilla. Fixation is a problem
when using this technique.

16.  Le Fort II Usually used for mid-face
advancement. Bilateral canthal and vestibular
incisions allow bone cuts at the Le Fort II level.
 Le Fort III Really a sub cranial craniofacial
operation using a coronal flap plus vestibular and
orbital incisions to move the entire mid-face and
molar complex.
 Malar osteotomy Used for post-traumatic defects.
Approach via coronal incisions. Risk to infra-
orbital nerve from maxillary bone cut.
Augmentation is an alternative.

17.  Rhinoplasty The correction of isolated nasal
deformity. Usually done intranasally,
supplemented by tiny incisions over the nasal
bones to allow bone cuts.
 ‘Open rhinoplasty’, which involves degloving the
nasal skeleton via a columella incision, is popular
particularly for cleft patients

18. references
 Oxford handbook of clinical dentistry( Bethany
Rushworth )seventh edition
 Internet.