Friday, May 25, 2012

Orthognathic Surgery

     Not all bite problems are a result of improper tooth alignment. There are certain individuals who have bite problems because of misaligned jaws. In other words, the upper and lower teeth don’t fit together properly because the bony bases that support the teeth are not properly positioned relative to one another. In orthodontics, we call this type of problem a “skeletal dispcrepancy.” This simply means that the upper and lower jaws have not developed in harmony with each other. Typical presentations of these jaw problems include underbite, overbite, crossbite, or jaw asymmetry.

     People who have severe skeletal discrepancies also have poor facial balance which negatively affects their appearance. When severe, surgical correction of the jaw positions is necessary to achieve proper facial balance. This type of surgical procedure is called “orthognathic surgery.” In our day and age, all orthognathic surgery must be done in conjunction with orthodontic treatment. Orthodontics is a crucial part of the process because the teeth must fit together perfectly when the jaw bones are reset. Therefore, every patient that needs jaw surgery will also have at least some movement of the teeth prior to the surgery being performed. This allows for a proper bite at the time of surgery. In addition, the attachments on the braces and wires allow the oral surgeon to use miniature elastics to hold the jaws closed during healing. The patient can then recover without having the mouth wired closed.
    
     The patient below is a professional singer who is in the public eye every day.  She had braces as a child but was unhappy with the way that her teeth looked.  She came to my office for a consultation hoping to resolve her concerns by wearing braces.  In every case, and especially in a situation like this, it is very important as an orthodontist to really understand the chief concern that each patient would like addressed.  As I looked in her mouth, I did see that she had some bite problems but they were not severe.  If my goal was only to fix the bite, I could have done that easily with braces alone. 

As we talked, however, it became clear to me that she was more unhappy with the structure of her jaws and lower face than the position of her teeth. 




In this picture you can see that in order for her to close her lips together, she has to flex the muscle of her chin. If the lips do not come together comfortably when all of the facial muscles are relaxed, it requires the chin muscle or "mentalis" muscle to flex in order to get the lips closed.  This is called mentalis strain or lip strain.  It can result from two skeletal problems.  First, the height of the lower face is too large requiring the lips to "reach" further to keep the mouth close. Second, when the lower jaw is behind the upper jaw, the lower lip can get "trapped" below the upper teeth requiring the chin muscle to flex and force the lower lip forward and up to get the lips together. In her case, both of these problems were present causing significant mentalis strain on lip closure.   




You can see from this picture that when she smiles, she shows an excessive amount of gum tissue. In orthodontics this is known as a "gummy smile." It can be the result of a very mobile upper lip that lifts higher than normal but more commonly is it a result of the upper jaw being positioned too far below the nose and cheeks. That is the case with this patient and it is a problem with structure of the craniofacial bones, not the position of the teeth.





In the profile view, the retruded position of the mandible is apparent.  The mentalis strain mentioned above is also evident.  A more forward position of the lower jaw and chin would go a long way to achieving proper facial balance.





A view of the occlusion shows that the lower front teeth are positioned behind the upper front teeth.  In orthodontics, this is called overjet but "overbite" is the term used in the general populations.  If facial structure were not an issue, the bite could be corrected using braces alone.





 
These views show that the jaws were somewhat narrow along with mild irregularities in the positions of several teeth.




This x-ray is called a panoramic x-ray and it shows that the wisdom teeth have been extracted.  Also, four premolar or "bicuspid" teeth were removed prior to her first set of braces when she was a child.  The orthodontics used the spaces gained from those extractions to align the teeth.




This x-ray is called a cephalometric x-ray and is very useful to the orthodontist and the oral surgeon in determining the position of the jaws and in planning the jaw movements that need to be made.




You can see the facial changes that were made using combined orthodontic treatment and orthognathic surgery.  The lower facial height decreased allowing for more relaxed lip closure.




The jaws were expanded resulting in a broader smile.  The upper jaw was also lifted resulting in less gum display when smiling.



The lower jaw and chin projection increased dramatically taking away the lip strain that pre-surgically was needed to close her mouth.  This procedure was done without any implanted chin material so the results will last a lifetime.


After removal of the braces, the teeth are well aligned


The overbite is no longer present




The width of the jaws has increased as well





The oral surgeon uses many plates and screws during surgery that stabilize the jaws while they are healing.  This "hardware" does not need to be removed.


This is the final cephlometric x-ray after the braces have been removed. 

The braces are removed several months after the surgery once the bones are totally healed and the bite has completely stabilized. Successful treatment of severe skeletal deformities of the lower face requires a team approach and precise planning on the part of the orthodontist and the oral surgeon. Those who undergo this treatment experience possibly the most dramatic improvements in facial appearance that exist in medicine today. While surgery is an amazing tool to restore harmony in jaw relationships, some bites that appear to be far off can be corrected using orthodontic treatment alone….especially in young people. We can help you determine if orthognathic surgery is right for you.