Oral Maxillofacial Surgery Orthognathic Surgery

Orthognathic Surgery is a procedure used for patients that have jaws that do not meet properly, which often coincides with teeth that do not seem to fit correctly with their jaws. This procedure is often used in conjunction with orthodontics, which straighten the teeth in preparation for the jaw surgery. People who require orthognathic surgery often have incorrectly positioned jaws, or an improper bite. Often the upper and lower jaws grow at different rates, which can lead to problems that affect speech, chewing, long-term oral health, as well as appearance.

Also, jaw alignment can also be influenced by injury to the jaw and birth defects. Orthognathic surgery basically repositions the jaw (Center for Oral and Facial Surgery of Chattanooga, 2000). This type of surgery is also used for patients that require jaw repositioning in order to allow for the reconstruction of the dentition using implants (Jones, 2002). More specifically, orthognathic surgery involves the "surgical manipulation of the elements of the facial skeleton to restore proper anatomic and functional relationship in patients with dentofacial skeletal anomalies (Patel, 2001).

The historical roots of orthognathic surgery date back to 1846, and the ability to effectively reposition the mandible preceded the ability to reposition the maxilla (Patel, 2001). Therefore, patients with primary maxillary deformities would somewhat ineffectively undergo mandibular surgery because it was the only option. Orthognathic surgery, as a distinct, specialized procedure, did not emerge until the possibility of effectively repositioning the maxilla in a consistent manner was demonstrated by Obwegeser in 1965. In 1970, Obwegeser was the first to report simultaneous repositioning of the maxilla and mandible (Patel, 2001).

The general goal of orthognathic surgery is to straighten the jaw. Patel (2001) explained how defining a straight jaw compared to a jaw that is not straight requires determination of the degree that a jaw deviates from a specified population norm. Furthermore, repositioning the jaw in order to achieve the restoration of the orthognathic form of a particular face is dependent on individual aesthetic characteristics of each patient.

Careful, meticulous analysis of the soft tissue using clinical examination, photographs, skeletal evaluation with standardized radiographs, and dental evaluations are required for the correction of maxillofacial deformities (Patel, 2001). The orthognathic surgeon must work closely with the orthodontist, dentist, and other professionals in the formulation of an effective treatment plan (Patel, 2001). Successful outcomes from orthongnathic surgery depend on several factors that are present prior to, during, and after the procedure (Patel, 2001).

Anomalies that require orthognathic surgery are usually a result of differential growth of the upper and lower facial skeleton, which leads to an abnormal relationship between the upper and lower jaws (Patel, 2001). This differential growth may be due to genetic predisposition or congenital anomalies, such as some syndromic conditions (Patel, 2001). In addition, traumatic events, such as injury, can also lead to discrepancies in the relationship between the upper and lower jaws, which may result in the disturbance of normal subsequent growth.

Other factors that may be involved in anomalies requiring orthognathic surgery include surgical resection, neoplastic growth, and iatrogenic radiation (Patel, 2001). The most common conditions requiring orthongnathic surgery are developmental anomalies (Patel, 2001). Assessment to determine the necessity of orthognathic surgery should be focused on the evaluation of the relative size and position of all facial skeletal elements, as well as the degree of zygomatic projection, and the relation of the maxillary and mandibular positions to each other and to the cranial-orbital region (Patel, 2001).

The surgeon should also take note of facial asymmetries, characteristics of the mouth and lips, as well as dental alignment and characteristics (Patel, 2001). There are three types of maxillofacial deformities that may require some sort of repositioning, including dental dysplasias, skeletal dysplasias, and dentoskeletal dysplasias (Patel, 2001). Dental dysplasias involve malocclusions resulting from dentition abnormalities and not from anomalies in the positioning of the jaws, which are generally corrected through orthodontic work and on orthognathic surgery. Skeletal dysplasias involve anomalies in skeletal positioning, when dentition is in good condition.

In these cases, the skeletal deformity must be corrected without alteration of the occlusion. Finally dentoskeletal dysplasias involve abnormal dentition along with abnormal relationships between the upper and lower jaws. Correction of dentoskeletal dysplasias involves both orthodontic work and orthognathic surgery. The decision to undergo orthognathic surgery should involve several questions, which indicate whether this procedure is appropriate for the situation at hand.

Questions that could be asked include whether the individual has difficulty in biting or chewing, whether the individual has noticed wear on their teeth, whether the individual likes their appearance from the front and side views, whether the individual has a protruding or recessive jaw line, whether the individual has an open bite, and if the individual suffers from sleep apnea. Answers to these questions will help guide the individual and healthcare professionals in their decision of whether or not to go ahead with orthognathic surgery.

Tools are also available that help surgeons to better assess the appropriate procedures for patients undergoing orthgnathic surgery. A simulation model of an orthognathic patient has been developed, which uses his or her computed tomography data (Noguchi & Goto, 2003). Simulated bone movements and osteotomies proved to help the researchers accurately analyze the movement of soft tissue and bone. The simulation model was able to.