[A mechanical carrier for the functional load of the mandible (author's transl)]

An apparatus is described in which mandibles can be suspended according to natural conditions. The masticator muscles can be simulated so that static equilibrium is ensured between these muscles, the two joints, and a resting point corresponding to the site of the incisors. As far as this is possible direction and force of the simulated muscles are respected. The total force at site of the incisors is about 24 kg. Holes were perforated at chosen sites in the compact bone. The deformation of these holes produced by tension or compression in the compact bone was measured by a capacitive transducer. In the 8 mandibles measured, tension characterized the pars alveolaris, compression the inferior edge of the corpus mandibulae. The highest values (tensions) were observed at the angular mandibulae (superior edge) and the lowest at the inferior edge of the protuberantia mentalis. Three mandibles were fractured and reconstructed with osteo-synthesis-plates. The load of 24 kg were applied at a rate of 1 to 2 per sec for approx. 15 min. The dislocation of the bony fragments produced by these loads oscillated between 19 and 47 micrometer. Repeated application of the load never produced a systematic increase of the displacement. The sites of measurement did not always show the displacement that might have been expected.