**4. Orthognathic surgery**

**Figure 1.** Orthodontic presurgical decompensation of class II malocclusion.

110 A Textbook of Advanced Oral and Maxillofacial Surgery Volume 2

closed before surgery

*3.6.2. Class III malocclusion*

carry out maximum mandibular setback.

Alignment and leveling and the need for extraction in skeletal class II malocclusion cases depends on the degree of crowding. In crowded cases, extraction of upper second premolars and lower first premolars is a common orthodontic plan in preparation for surgical correction. The extraction of upper second premolars prevent further retroclination of upper incisors and the extraction of lower first premolars facilitate uprighting of lower incisors and subsequently establish enough overjet for surgery. We should bear in mind that extraction space should be

In skeletal class III malocclusion cases the natural dental compensation involves proclination of the upper incisors and retroclination of lower incisors. Therefore, in these cases, orthodontic decompensation is achieved by uprighting the upper incisors and proclining the lower incisors and thereby increasing the reverse overjet to the maximum which would allow the surgeon to

Similar to skeletal class II patients, in these cases also the alignment and levelling and the need for extraction depends on the degree of crowding. The usual pattern of extraction in these cases involves the extraction of upper first premolars in order to facilitate the uprighting of upper incisors and extraction of lower second premolars in order to prevent further retroclination of the lower incisors. These extractions also help to establish enough reverse overjet for the

surgical procedure. Extraction space should also be closed before surgery. (Figure 2)

Skeletal dentofacial deformities are associated with numerous problems including: esthetic, functional, psychological, speech, mastication, digestion, and possible temporomandibular joint dysfunctions.

Orthognathic surgery is a hospital based operation in which the elements of the facial skeleton are manipulated to restore the proper anatomic and functional relationship in patients with skeletal dentofacial deformities and overcome the above mentioned problems. The results of orthognathic surgery can have dramatic and positive effects on many aspects of the patient's life.

Orthognathic surgery is done through a variety of osteotomies including maxillary segmental osteotomies, Le Fort I maxillary osteotomy, Le Fort II osteotomy, Lefort III osteotomy, sagittal split osteotomy of the mandibular ramus, vertical ramal osteotomy, inverted L and C osteot‐ omies, mandibular body segmental osteotomies, and mandibular symphysis osteotomies.

After the surgery, patients should expect the following:

