Le chirurgie orthognathique est une intervention pour corriger les déformations dentofaciales, qu'elles soient congénitales ou acquises, et vise à rétablir un équilibre fonctionnel et esthétique. Elle est indiquée pour divers problèmes tels que les malocclusions, les douleurs au niveau de l'articulation temporo-mandibulaire et des troubles respiratoires. Le traitement comprend une évaluation clinique et radiographique, suivie d'une planification chirurgicale et d'une orthodontie pré et post-opératoire.

1. Orthognathic
Surgery

2. Introduction
Surgery to treat facial disproportion
or surgery for correction of
dentofacial deformities which could
be congenital or acquired.
Orthognathic surgery to reposition
the maxilla, mandible, or chin is the
mainstay treatment for patients who
are too old for growth modification
and for dentofacial conditions that
are too severe for either surgical or
orthodontic camouflage.

3. Malocclusion and associated abnormalities of the skeletal components
of the face can occur as a result of a variety of factors, including:
• Inherited tendencies,
• prenatal problems,
• systemic conditions that occur during growth,
• trauma,
• and environmental influences.
environmental influences (Ankylosis) inherited tendencies (Craniocytosis)

4. • Function: to establish a functional occlusion aiming to achieve
normal overbite/overjet and transverse relationships.
• Aesthetics: to normalize facial balance and proportions in three
dimensions, in addition to provide stable results in the long-
term.
• Other possible benefits:
* Temporo-mandibular joint dysfunction.
* Mouth opening
*Sleep apnoea
*Traumatic occlusions and dental health
Treatment Objective

5. • Difficulty of chewing
• Difficulty of swallowing
• TMJ pain and headache
• Open bite.
• Unbalanced facial appearance
• Facial injury(post traumatic defect)
• Birth defects
• Lip incompetence
• Mouth breathing
• Sleep apnea
Indication of Orthognathic Surgery

6. • History
• Clinical examination ( Investigation Facial evaluation ( Frontal view , Profile
view ), Dental examination, After. completion of clinical examination then
Radiographic examination (Lateral cephalometric , CBCT , OPG ), Model
analysis0)
• Initial diagnosis
• Treatment plan
• Pre-surgical orthodontics
• Surgery
• Post-surgical orthodontics
• When appropriate, restorative dentistry, psychological intervention or support
and speech therapy will be required.
The management protocol for facial deformity should
comprise the:

7. • Plaster of Paris models from the maxilla and mandible are taken and the
actual centric occlusion of the patient is recorded. The models are oriented in
a semi adjustable articulator after face-bow transfer.
• The models allow analyzing the: (occlusion, shape of the dental arches,
position, size and shape of the teeth, position of the jaws in relation to the
skull base)
• Usually two sets of models are used.
• One is kept to analyze and document the preoperative situation.
• The second set of models is used to perform mock surgery (if no need for
presurgical orthodontic treatment, but if we need orthodontic treatment, a
new sets of cast is obtained after the orthodontic correction and the mock
surgery is performed on the new casts).
Model analysis (study casts)

9. • Mandibular prognathism/ progenic ( usually corrected by either
vertical subsigmoid, body Osteotomy,bilateral sagittal split
osteotomy(BSSO))
• Mandibular retrognathism/ retrogenic (usually corrected by
bilateral sagittal split osteotomy, inverted L osteotomy,
segmental osteotomy)
• Chin in deformities. (Usually corrected by geniplasty)
Orthognathic Surgical Procedures of Mandible

10. Indications :
• mandibular excess where set back is required
• Relieving osteotomy to allow rotation of the mandible
when BSSO is done on the contralateral side.
• Vertical Subsegmoid Osteotomy
Uses:
Advance or set back
Asymmetry
Close small open bite deformity
2. Bilateral Saggital Split Osteotomy

11. Dentoalveolar segment of mandible is moved anteriorly, allowing
correction of Class II malocclusion without increasing chin prominence.
Indication:
1.Good facial profile with the chin in the desired antero-posterior position
relative to the cranial base.
2.Vertical and transverse arch discrepancy
3. Total Subapical Osteotomy

12. • Carried either anterior or posterior to the mental nerve
• A preplaned segment of bone is removed either to close
an edentulous space or following an extraction (usually a
premolar) allowing the anterior segment to be set back
• If posterior to the mental foramen the nerve has to be
dissected free
4. Body Osteotomy
• May be performed as either a solitary procedure or in
combination with other orthognathic procedures.
• Anteroposterior repositioning: Advanced or set back
• Augmented or reduced in vertical dimension
• Rotated to correct center line discrepancy
5. Genioplasty

13. • Maxillary Excess
Maxillary Orthognathic Surgery
• Excessive growth of the maxilla may occur in the anteroposterior, vertical,
or transverse dimensions. Patient with maxillary excess appear to have :
elongation of the lower third of the face; a narrow nose, particularly in the
area of the alar base; excessive incisive and gingival exposure; and lip
incompetence.
• Maxillary and Midface Deficiency
• Patients with maxillary deficiency commonly appear to have: (a retruded
upper lip, deficiency of the paranasal and infraorbital rim areas, inadequate
tooth exposure during smile, a prominent chin relative to the middle third of
the face).

14. • Maxillary Segmental Osteotomy
• where only part of the maxilla, including the
teeth and usually the anterior part is
osteotomized and repositioned.
• Many types and approaches is used in maxillary
segmental osteotomy but the most popular
procedure is Wassmund technique
• Can be usedin advancement (anterior repositioning)
• Inferior repositioning, Superior repositioning
• No posterior repositioning can be done (sometimes
small posterior movement can be done)
2. Lefort I Osteotomy

15. 3. Lefort II Osteotomy
• For patients with central midface hypoplasia, it allow
advancement (anterior repositioning)
andlengthening ( inferior repositioning of the central
midface)
• Rigid fixation with plates and screw to stabi lized the
segment.
• It is lie in craniofacial surgery
• Advance the entire face mass by separating it from the
cranial base using coronal flap as an approach.
• Advance the maxilla and increase the orbital valium
4. Lefort III Osteotomy

16. Distraction Osteogensis
• One new approach to correction of deficiencies in the mandible and the maxilla
involves the use of distraction osteogenesis (DO ) . When correcting deformities
associated with these deficiencies, the conventional osteotomy techniques have
several potential limitations.
• When large skeletal movements are required, the associated soft tissue often cannot
adapt to the acute changes and stretching that result from the surgical repositioning
of bony segments.