The sequelae of insufficient vascularity following maxillary orthognathic surgery can vary from loss of tooth vitality, to periodontal defects, to tooth loss to loss of major maxillary dentoalveolar segments. The literature is replete with reports of the successful surgical treatment of maxillary and mandibular skeletal deformities. It is unusual, however, to see a report of the case that failed. Understanding the blood supply of the maxilla and how possible patient related, anesthetic and operative factors affect it, is important in understanding how the vascularity of the maxilla can become compromised in a surgical procedure. Avascular necrosis of the maxilla is a rare complication of orthognathic surgery with few cases reported in the literature. There are identifiable risk factors that can influence the blood supply of the maxilla. Careful preoperative assessment is required to exclude patient factors that have the potential to affect tissue vascularity. This in conjunction with sound anesthetic and surgical technique should all minimize the risk of avascular necrosis. Even so it is still possible for this rare complication to occur.
Key words: Avascular Necrosis, Orthognathic Surgery, osteonecrosis.