Clasps according to the planned design, Müller thorns (preformed elements)
Function:
Retrusive movement of the mandible
Description:
Müller thorns are built in reversed (exchanging left and right)
In appliances of patients which present a class III, the surfaces on which the thorns glide along are directed mesially. Again, the mandibular plate is finished and polished first.
The thorns are fixed with wax as mentioned before onto the lower plate. The finished mandibular plate is covered with wax to avoid sticking on the maxillary plate. Now acrylic can be applied on the upper plate and the fixator has to be closed while the acrylic is not yet polymerized.
