The advancement double plate (VD, VSD) is an orthodontic treatment device for the therapy of an Angle Class II (mandibular recession, distal bite). It was developed by Schwarz and later modified by Sander.The following Angle classes are distinguished:
- I – neutral bite (correct toothing).
- II – Distal bite (mandibular recession).
- II-1 – Distal bite with protruded (protruding) maxillary front.
- II-2 – Distal bite with retruded (protruding) maxillary front.
- III – Mesial bite (lower jaw is too far forward).
An advancement double plate combines the possibilities of functional orthodontics with those of active plate appliances.
The procedure
An advancement double plate consists of two active plates for the upper and lower jaw.
To determine which position the mandible should be placed in using a VSD, a construction bite is taken. For this purpose, the two jaws are brought into the position that is to be achieved later with the aid of the VSD. A heated wax plate or some plastic material is applied to the rows of teeth and the jaw is then closed in the desired position, guided by the experienced orthodontist. After the material has hardened, this bite, along with impressions of both jaws, can be given to an orthodontic laboratory for fabrication of the plate. There, the plates are fabricated in an articulator (artificial jaw joint).
Guide spurs or bars are attached to the center of the upper plate, which cause the lower jaw to be moved to a more anterior (front) position when the mouth is closed. The bars slide into the correct position during closure via an inclined plane incorporated into the mandibular plate. The inclined plane is inclined at an angle of 60° to the occlusal plane.
The bars can also be attached laterally to the maxillary plate (Müller spurs).
At the same time, the active plates can provide transversal shaping of the dental arches (widening) and movement of individual teeth. In the case of a gapped, protruded (protruding) maxillary front, a tongue guard can be attached to the appliance to keep the tongue away from the front teeth and thus achieve correct shaping of the front.
The appliance is used when the children’s growth is at its greatest, as the advancement is intended to reinforce and exploit condylar growth. The prerequisite for the effect is mouth closure, so compliance (cooperation) of the children is very important.
The plates must be worn for about 14-16 hours a day. They must be taken out for sports.
The advancement double plate can also be made as a retraction double plate, so that retraction of the mandible is possible in case of mesial occlusion (mandible is too far forward).
Benefit
Mandibular recession, or distal bite, is the most common malocclusion in orthodontics. The most optimal treatment results are achieved when children are treated while they are still growing. Tooth and jaw misalignments are influenced while they are still developing in order to achieve a harmonious, functionally and aesthetically optimal result.
