The divided activator with screw for the upper jaw
Elements:
Labial bow and retention thorns 0.8 mm spring hard
Function:
Separate expansion of the maxilla
Description:
In this horizontally divided bimaxillar appliance, the upper expansion screw is anchored in the lower jawin diesem horizontal geteilten bimaxillären Gerät ist die Oberkiefer- Dehnschraube im Unterkiefer verankert
The elements are bent following the design, in this case, additionally with two protrusion springs. The extension of the acrylic base is limited with wax. In this horizontally divided appliance, after bending the elements, the lower jaw is finished separately and polished.
In the interocclusal area, the upper and lower bite blocks of the divided activator show a separation of almost one millimeter. That is the reason why this area is covered with wax to this height.
In the upper jaw, the screw is centered and fixed with wax so that the retentions of the screw stick out into the lower jaw. Therefore, in the anterior region, two notches have to be grinded into the lower base plate. The fixator should be able to open and close without interference. The area of retention in the lower jaw is blocked out with wax.
Now acrylic is added on the upper jaw. While the acrylic is still malleable the fixator is closed. The wax layer in the retention area of the screw prevents the union of the upper and lower plate. This way the upper plate can be sawed, finished and polished separately.
After this, both separately produced plates are unified to one appliance. For this purpose, the division and the interocclusal area close to the screw are covered with wax. Now the retentions of the screw are polymerized into the lower plate and therefore both plates are unified to one bimaxillar appliance.
The upper part of this activator can be expanded without the lower jaw.
