A quad helix (or quadhelix) is an

orthodontic Orthodontics is a dentistry specialty that addresses the diagnosis, prevention, management, and correction of mal-positioned teeth and jaws, and misaligned bite patterns. It may also address the modification of facial growth, known as dentofacial ...

appliance for the upper

teeth A tooth ( : teeth) is a hard, calcified structure found in the jaws (or mouths) of many vertebrates and used to break down food. Some animals, particularly carnivores and omnivores, also use teeth to help with capturing or wounding prey, tear ...

that is cemented in the

mouth In animal anatomy, the mouth, also known as the oral cavity, or in Latin cavum oris, is the opening through which many animals take in food and issue vocal sounds. It is also the cavity lying at the upper end of the alimentary canal, bounded on ...

. It is attached to the molars by 2 bands and has two or four active

helix A helix () is a shape like a corkscrew or spiral staircase. It is a type of smooth space curve with tangent lines at a constant angle to a fixed axis. Helices are important in biology, as the DNA molecule is formed as two intertwined helices, ...

springs that widen the arch of the mouth to make room for crowded teeth, or correct a posterior cross-bite, where lower teeth are buccal (outer) than upper teeth. It is usually made from 38 mil stainless steel wire and is primarily indicated in mixed dentition, cleft patients and those that have performed the act of thumbsucking. A variety of this appliance is inserted into attachments that are welded to the bands. In this way the orthodontist can adjust the appliance without removing the bands. The precursor to the quad-helix was the coffin spring. Similar devices known as tri-helices and bi-helices were later developed, with three and two helix springs, respectively. The expander works by gently pushing the teeth outwards to eventually widen the upper arch. A quad helix expander is usually given to those who have a narrow top jaw, a cross bite and/or crowded teeth.

References

Orthodontic appliances Dental equipment {{dentistry-stub