[The development and action-mechanism of the quadhelix in orthodontic treatment]

Authors present a historical review of the development of quadhelix appliance. In conclusion, slow maxillary expansion with the quadhelix appliance provides an alternative approach to rapid maxillary expansion that is particularly beneficial for correction of transverse and arch-length discrepancies during the mixed dentition. There are numerous indications for this approach with two major advantages. First, a lower force that is within the elastic limits of maxillary sutural and periodontal tissue is generated. Second, a low separation rate of 0.4-1.1 mm per week allows for more physiologic adaptation to the expansion that may result in a more stable correction with less sutural relapse. The quadhelix is a versatile appliance that provides practitioners a convenient means to normalize developing malocclusions.