[Relapse and alteration of results in orthognathic surgery].

Orthognathic surgery is a surgical technique that provides normalization of the face and occlusion. Some malocclusions are particularly unstable, such as maxillary transversal deficits, and anterior open bite. Many factors are implicated in the stability of surgical results. Indeed, facial balance largely depends on functions that could be the cause of unstable results, despite a good anatomical correction. Breathing, swallowing, chewing disorders and more largely alteration of the functional matrix may be sources of instability. These dysfunctions are the first cause of relapse. Others constitutional factors can also be involved in relapse. Understanding oro-facial functions and rules determining cranial and maxillo-facial balance is mandatory for the surgeon to ensure a long-term stability of procedures.