An underbite, or a class III bite orthodontically, can occur from one, or both, of two scenarios. In a class III patient, either the top jaw has not developed forward enough in its relationship with the lower jaw, OR the lower jaw has grown forward excessively in its relationship to the top jaw. Commonly, patients with an underbite have a combination of both situations described above where the top jaw is too far back, and the bottom jaw is too far forward. Early treatment of this type bite is recommended in order to attempt avoiding future jaw surgery to correct the issue. Below are the appliances aimed at correcting this type of problem.
Removable Expander
The removable expander is a functional appliance used to expand the upper dental arch by stimulating bone growth in the midpalatal suture. In the instance of a patient with an underbite, this type of appliance also has a component that gently stimulated the devolopment of the upper anterior teeth into a more forward position, thus "jumping" the patients underbite to a more normal relationship.
It is a full coverage (covers the teeth and palate) acrylic appliance with expansion screws inserted in the middle to facilitate opening of the appliance. The screw is opened, as instructed by Dr. Moshiri, until the palate has been widened, and the anterior bite has been corrected. The appliance is then worn, without activation, for a period of roughly six months as a retainer to facilitate proper healing and retention of the new bone width.
Download our Removable Expander handout for more information.
Removable Expanders demonstration video.
Click here to view our introduction to Expanders video.
Facemask Appliance
Reverse-pull headgear, or a face mask, is a removable appliance used in correction of a class III skeletal malocclusion, due to an underdeveloped upper jaw and slightly overdeveloped lower jaw. The appliance is worn for a minimum of 14 hours per day, after school, to help pull the upper jaw forward in growing children and adolescents. Several skeletal and dental changes are achieved with this early treatment to improve the malocclusion and the soft tissue profile. The earlier the correction and the longer the treatment time, the greater the chances that the maxillary protraction will be maintained.
***Following facemask therapy, the Class III growth pattern reasserts itself; therefore vigilance in continuing to follow-up during retention is recommended.
Download our Facemask handout for more information.