[Biophysical foundations in the application of electromagnetic fields in the modification of osteogenesis]

The interactions between bone-forming cells and the extracellular processes determining the mineralisation of the osteoid with electric and/or magnetic fields is the elementary prerequisite. The magnetic or electric field or the combination of both, as well as their time related intensity are discussed as the stimulating factors. When using electric current there is a physical process to be considered. This process consists of changes of metabolites caused by the cathodic electrode reaction which may gain influence on the metabolism of bone-forming cells and the mineralisation. According to the results of this investigation the bone-producing effect of the cathodic electrode reaction saturates+ at a geometric current density of about 0.4 microA/mm2. Apart from the changes of metabolites produced by the electric current there are electric polarizations in front of interfaces and cell membranes due to local ion concentrations caused by even very weak electric fields.