Orthognathic Surgery................pptx

Orthognathic surgery
Surgery for correction of facial deformities caused by protraction of maxilla and mandible or retraction of mandible and maxilla or both

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)

8. 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

9. 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

10. 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

11. 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

12. 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).

13. 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

14. 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

15. 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.