21 January 2015
Herbst Appliance & Airways
What do you need to know about the Herbst appliance?
Using a cephalometric x-ray (the one that takes images from the side of the head (see fig 1), an orthodontist can properly diagnose whether the orthodontic issue is skeletal or dental in nature. If the issue is skeletal, the only way to properly address and correct such is by way of a growth modification appliance such as the Herbst. This growth modification should be performed at an “ideal” time to be effective. If done too early, it will not last. If done too late, it will not be effective and jaw surgery will be required to correct the problem.
Therefore, if an orthodontist has diagnosed your child’s orthodontic issue as being skeletal in nature, treatment with rubber bands will not provide a solution.
Benefits of the Herbst?
Upper airway narrowing is connected to several breathing problems which include obstructive sleep apnea. Upper airway narrowing most commonly occurs in the space directly behind the tongue called the oropharynx. A small or narrow oropharynx is often linked to a retrusive (posterior) lower jaw position. It is worth noting that approximately 25% of the children that visit an orthodontist have a lower jaw that is positioned too far posteriorly which puts them at risk for either having or developing airway problems later in life.
In the simplest of terms, the Herbst appliance positions the lower jaw into a more forward position. In clinical research, Iwasaki verified that orthodontic treatment with a Herbst appliance can significantly enlarge the oropharynx, thereby opening the upper airway and minimizing the risk of developing airway issues later in life (see figure 2). Further research by Shutz showed that the Herbst appliance, used in conjunction with expansion of the upper jaw, will increase the volume of the pharyngeal airway and relieve the symptoms of obstructive sleep apnea. Lastly, Pancherz showed thorough additional clinical research that the Herbst appliance is most effective when used near the pubertal growth spurt. It is for the reason that the American Association of Orthodontists recommends that all children have a screening, performed by an orthodontist, at age 7.
Therefore, as one can glean, proper diagnose and efficient timing of treatment is essential to effectively treat a child with orthodontic issues of a skeletal nature using growth modification. The answer of “what should we do” in such a case that one orthodontist has recommended a Herbst while a second recommends rubber bands comes squarely down to the doctors’ diagnosis. If, in fact, the problem is skeletal, rubber bands are not a viable solution.
Dr. K Britt Reagin has been educated in orthodontic and dento-facial orthopedics and can monitor your child using radiographs to determine if and when your child will benefit the most from growth modification such as the Herbst.
Figure 1. An example of a cephalometric x ray used by orthodontist to determine if your orthodontic problem is dental or skeletal in nature. This radiograph can also be used to determine if you child is near the pubertal growth spurt.
Figure 2. Courtesy of Iwasaki. A. Shows a child with an obstructed airway prior to growth modification. B. Shows the same patient after the Herbst appliance. Notice then enlargement of the red cavity which is the airway.