Which appliance is a fixed tooth-borne maxillary expansion appliance?

Which appliance is a fixed tooth-borne maxillary expansion appliance?

• A. Hyrax appliance
• B. Haas appliance
• C. Quad Helix
• D. Edgewise

Answer: (A)

Maxillary expansion appliances can be anchored to teeth (tooth-borne) or to bone. The Hyrax is the classic fixed tooth-borne expander: a metal framework cemented to bands on the maxillary molars with a central jackscrew. When you activate the screw, the teeth are pushed outward to widen the maxilla, and the appliance stays in place (non-removable by the patient). This combination of being anchored to teeth and being permanently fixed in the mouth is what defines it as a fixed tooth-borne expander.

Maxillary expansion appliances can be anchored to teeth (tooth-borne) or to bone. The Hyrax is the classic fixed tooth-borne expander: a metal framework cemented to bands on the maxillary molars with a central jackscrew. When you activate the screw, the teeth are pushed outward to widen the maxilla, and the appliance stays in place (non-removable by the patient). This combination of being anchored to teeth and being permanently fixed in the mouth is what defines it as a fixed tooth-borne expander.