A hyrax is used to create more room in the mouth for teeth. This can help prevent extractions of permanent teeth in the future and also improve the way developing teeth erupt in the mouth.
Hyraxes also are used to correct a crossbite, which occurs when the upper jaw is narrower than the lower jaw and therefore upper teeth are biting inside the lower teeth rather than outside. A crossbite can cause the patient’s bite to shift in an unfavorable way and their face to grow asymmetrically. The hyrax will widen the upper jaw so that the bottom and top teeth fit together properly.
A hyrax is custom-made for each patient and consists of bands that are cemented to the molars and connected to a screw. It is activated at home when the patient turns it by using a special key that fits in a hole in the screw. When the desired amount of expansion is achieved, the hyrax will remain in the mouth for several more months in order for new bone to fill in.