Doctors William and Robert Wilson designed and popularized the 3D® system. This system includes multiple devices and accessories that work in conjunction with other types of fixed orthodontic appliances. They are all removable / fixed, ie, removable for clinicians, but fixed for patients. Indeed, with the exception of the 3D® distalizing arch, all devices and accessories of this system fit vertically inside lingual fasteners. Thus, to make their adjustments, practitioners can remove and return the devices, without removing the rings.