The present study intends to clarify whether there is positional mandibular stability in patients to be submitted to orthognathic surgery. In case of any instability exists, it is needed to understand if this could be related to a particular type of dentofacial deformity or could have any short-term or long-term influence on outcomes of the orthognathic surgery.

Treatment of skeletal discrepancy nowadays is mainly performed by combination of clinical and surgical procedures in which orthodontics intends to align the teeth according to their respective alveolar bone and the surgical procedure - orthognathic surgery - realign the jaws in an adequate position among themselves and related to the rest of the craniofacial skeleton. Orthognathic surgery has developed throughout the years technically as well as regarding fixation devices for the operated segments, providing prediction of results with a low complication incidence. A debate point is related to the possible instability of the mandibular position as a reference for surgical planning due to its articulation with the temporal fossa, the temporomandibular joint. However, studies have shown that not always the mandible position obtained for the articulator reflects the position observed in subjects after induction of general anesthesia. Since there is no evidence that indicates that any alteration of the position of the mandible could influence the outcomes of a orthognathic surgery nor any relationship of a certain type of dentofacial deformity that would be beneficiated by an specific order of surgery or skeletal reference (maxilla or mandible), the present study intends to clarify some of these questions.

Inclusion Criteria:

• Dentofacial Deformity candidate to orthognathic surgery;
• Systemically capable to be submitted to the orthognathic surgery.

Exclusion Criteria:

• Patient's health condition is not stable enough to guarantee uneventful outcome;
• Required data unable to be achieved;
• Patient not agreeing to participate to the study.

Data will be obtained from subjects to be submitted to orthognathic surgery by the Department of Oral & Maxillofacial Surgery of the Hospital Geral Universitário of the city of Cuiabá - Brazil during the period of March 2012 through March 2013. Considering the local demand, thirty subjects are expected to be included in the research.