Approximately 5% to 7% of the United States population is believed to have skeletal facial deformities resulting in jaw malrelationships. Often in these situations, orthodontic treatment alone may provide an unstable and unpredictable solution to a severe malocclusion (bad bite relationship) and the result may be significantly compromised. Therefore, orthodontia, in conjunction with jaw surgery may be necessary to achieve a proper result. Following are different skeletal irregularities that orthodontics in conjunction with orthognathic surgery can address to improve the ability to chew, speak, breathe and in many cases enhance appearance:

Overbite (Class II malocclusion)
In this type of bite the upper teeth and jaw occlude forward to the lower teeth and jaw. This pattern is often associated with "buck tooth" appearance or a receding lower jaw, often called a weak chin. On overbite can be caused from a forward overgrowth of the upper jaw, a receding lower jaw or both. This is the most common form of jaw dysplasia.

Extraction of teeth was the only solution used in the past to improve the teeth relationship in class II bites; but this was often done at the expense of arch form and facial esthetics often resulting in a flattened facial appearance. Now braces are used in conjunction with oral surgery to provide the patient with the best overall combination of form and function.


Underbite (class III)
An underbite is when the lower teeth and jaw protrude forward to the upper teeth and jaw. Often this results in chiping or wear in the front teeth due to a "traumatic" bite. The facial profile is often "concave" in appearance due to the prominence of the chin. This is caused from an underdevelopment of the upper jaw, and over development of the lower jaw, or a combination of both. The proper treatment is to correct the alignment of the teeth followed by the appropriate surgical prodecures. New techniques in holding the surgical result has made this a predictable and stable procedure that can greatly improve function and facial esthetics.


Crossbite (Transverse discrepancy)
A crossbite occurs when the upper teeth bite inside of the lower teeth. Patients with crossbites often have a narrow high palate and often the smile appears too narrow in form. In a growing patient, this condution can usually be corrected orthopedically with a palatal expansion appliance. In patients whose growth is completed surgical intervention may be necessary to address this condition.


Gummy Smile (maxillary vertical excess)
When the upper jaw grows down excessively the patient may display extra gum tissue when smiling. In addition, the lips usually will not close when relaxed and the upper front teeth appear too full. Often this diagnosis is combined with other previously discussed problems. Such esthetic problems often are not completely treatable by orthodontic tooth movement alone and could require jaw surgery to correct and stabilize the result.


Open Bite (Apertognathia)
This skeletal deformity often results from downward growth of the back portion of the upper jaw. This condition can create muscle imbalance with subsequent deformities of the upper and lower jaw. Abnormal tongue habits, unusual speech patterns, thumb/finger sucking, poor lip musculature, and nasal passage pathology have all be implicated as possible causes or contributing factors. Often these patients have difficulty chewing food - specifically incising or cutting food when they initially bite. Another area of concern is the potential for these patients to have increased TMJ problems. Although there is little evidence that a dental malocclusion directly results in TMJ problems, there seems to be a higher correlation between jaw problems and skeletal deformities.


Asymmetry
Asymmetry usually develops from a discrepancy between the growth of the right and left sides of the upper or lower jaw structures. This can result from pathology, trauma, a birth defect, or even personal habits. Asymmetries are difficult to treat without a complete interdisciplinary analysis involving the oral surgeon and the orthodontist. Surgical correction to center and align the jaws typically creates a significant improvement in facial balance, function and esthetics.


TMJ Disorder and Orthognatic Surgery
There is a significant controversy about the relationship of TMJ disorders and dentofacial deformities. A true scientific relationship between the two does not exist; however, there seems to be a high correlation among malocclusion, skeletal deformities, and TMJ problems. Surgical treatment is directed at correcting the bite. TMJ symptoms may improve with the surgery or may need to be addressed with additional procedures and the enforcement of a thorough TMJ regimen involving consisting of a soft food diet, mild physical therapy and anti-inflammatory medication to improve the TMJ symptoms.


Orthodontic and oral surgery team approach
Treatment is initiated by the orthodontist. Dr. DiGiovanni's and Dr. Cook's job is to properly align the teeth so that when the jaw is surgically moved the teeth will fit together properly. After the surgery further orthodontic tooth movement is necessary to finalize the result. Although for every patient the timing of treatment is different, a common scenario is as follows: 1. 6-12 months of presurgical orthodontic treatment 2. Orthognathic surgery procedures 3. 6-12 months of post-surgical orthodontic treatment.


Summary
Since the introduction of orthognathic surgery more than 30 years ago, there has been a continous trend toward improvement in techniques and materials. If indicated, orthognathic surgery can be an optimal way to correct a specific dysfunction as well as give the patient an overall improvement in the quality of life.