Hemifacial Microsomia, Jaw Anomalies and Chin Deformities



Hemifacial Microsomia

Hemifacial microsomia is a congenital condition where one side of the face is smaller than the normal side.  The extent of hemifacial microsomia can be isolated to a smaller lower face and cheek without any other problems of growth disturbance of the mandible (mandibular hypoplasia), absence or deformity of an ear (microtia) and orbit as well as a smaller mouth opening.  The cranial base could be smaller as well.  The surgical treatment depends on the degree of deformity.  If the mandible growth and occlusion is normal but the soft tissues of the face on the effected side are smaller, then fat grafting to fill in the soft tissues is a useful and important treatment to restore symmetry and balance of the face.  If the mandible growth is disturbed and the mandible is smaller than the normal side, this will create an occlusal cant and the degree of the occlusal cant will determine surgical intervention.  When the occlusal cant is mildly asymmetric, then orthodontics alone may be enough to correct the malocclusion.  If the occlusal cant is moderate or severe, then corrective jaw surgery will be needed.  Timing of jaw surgery will depend on the severity of the problem. Microtia will require total ear reconstruction and most likely auditory canal reconstruction.  For microstomia (smaller mouth opening), an operation to widen the oral commissure is performed.

Jaw Anomalies

Jaw anomalies may be congenital or caused by accidental or surgical trauma.  Congenital jaw anomalies include Class 2 and Class 3 malocclusion, and hemifaical microsomia, where one side of the face and jaw are smaller than the normal side.  Jaw anomalies may be differentiated from having a weak chin, called microgenia.

A normal dental occlusion or bite is called a Class 1 occlusion.  It is defined by the relationship of the mesiobuccal cusp of the maxillary (upper) first molar to the mesiobuccal groove of the mandibular (lower) molar teeth.

An overbite, or Class 2 malocclusion, exists when the maxillary (or upper) teeth are more forward than your mandibular (or lower) teeth.  This typically is due to micrognathia (or small lower jaw).

An underbite, or Class 3 malocclusion, is a misalignment of the teeth, when the upper teeth is less forward than the lower teeth from a lateral view.  The reasons for this occlusion may be from a recessed upper jaw, or a very prominent lower jaw or a combination of both recessed upper jaw and prominent lower jaw.

If the degree of movement to correct a Class 2 or Class 3 malocclusion is relatively small, then orthodontic treatment alone may be enough to solve the malocclusion.  If the degree of malocclusion is moderate to severe, then only surgical treatment will correct the malocclusion.  Sometimes, an orthodontist will try to tip the teeth too much in order to correct a moderate malocclusion, which may lead to problems later on.  Therefore, it is beneficial to have a comprehensive evaluation for any type of jaw anomaly with an Orthognathic Team, that is comprised of a Craniofacial Plastic Surgeon, an oral surgeon, an orthodontist and dentist.  The communication between these specialists is important to providing the proper options and timing for orthodontic and surgical treatments.

I have over 16 years of experience treating jaw anomalies and work closely with Dr. Gerald Geldzahler (oral surgeon), Dr. David Zirlin (pediatric dentist) and Dr. Julia Starobinets (orthodontist).  Here, we will give you honest opinions and options of treatment based on many years of experience.

Chin Deformities

Microgenia, or small chin, is not desirable to many people because of the way it distorts the face.  A strong looking jaw is considered to be more masculine, even before the Greek Gods were created.  In order to correct the problem of a small chin, an implant is needed.  There are two types of implants: silicone and porous plastic.  I prefer the porous plastic implant because your own tissue will grow into the implant and there is less risk of migration and infection.  The surgical approach that I prefer is an incision under the chin.  This allows easy access to the lower part of the mandible (chin) and offers less risk of mental nerve injury and infection.  It is important to have an overall evaluation of your jaw and to make sure the weak chin is not caused by malocclusion.

Improving the jaw line with a chin implant can significantly transform the way a person looks.  Because the implant is permanent, implant choice and surgical technique are both important.

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