The disclosure includes an ignition control circuit comprising a transformer having at its secondary side an operating winding, and at least one filament winding. Means for creating 3D shots of a partial volume of the mandibular arch are also provided, said 3D shots being created especially by a second image receiver for creating a 2D shot and means for taking a plurality of 2D shots from different directions and creating a 3D sot therefrom, preferably according to conebeam technology with the associated reconstruction algorithms. A foam layer sits on top of the spring plate and a weight plate sits on top of the foam layer.