Anatomy of Class II AppliancesThe MARA consists of a square tube soldered to the buccal of the upper crowns. The "arms" slide into these tubes and extend down to the lower molars where they contact the MARA stops.
Herbst: Appliance without a mechanism in place. Hex screws (not pictured) will screw screw into the upper and lower pivots to secure the advancement mechanism.
Herbst: Hex screw and pivot securing the upper half of the advancement mechanism.
Herbst: Fully activated Herbst mechanism.
X-Bow: Lower rod slides into the upper spring and the limitations that the Gurin locks present force the lower jaw to rest in a protruded position. Over time, bone will develop in the lower condyle and the protruded position of the lower jaw will become natural due to the growth of the condyle.
X-Bow: A thick wire that is connected to the spring mechanism is secured to the upper band via the headgear tube.
X-Bow: The rods on each side are limited to how far they are able to slide along the labial arch due to the presence of the Gurin locks that are held in place just mesial of the lower first bicuspids on each side. In addition to the lower lingual arch, the lower labial arch is bonded to the facial of the anterior teeth to provide maximum arch stability.
MARA: Fully activated MARA. Hooks soldered to the upper crown and elbow are held together by a ligature tie and secure the elbow to the crown.