Effect of Faradic products on direct current-stimulated calvarial organ culture calcium levels

Calcium release from mouse calvarial organ cultures was used to analyse the well-described biological effects of constant direct current (20 mu A) in combination with Faradic products generated at a titanium wire cathode. Con stant 20-mu A direct current stimulation alone, delivered by agar salt brid ges, consistently lowered the media calcium levels. Direct exposure of calv ariae to a titanium cathode and its faradic products resulted in further lo wering of media calcium levels and also a significant increase in the media pH. Hydrogen peroxide is a faradic product of the titanium cathode, microm olar amounts being generated by our system over 24 hr. H2O2 is pro-resorpti ve whereas elevated pH stimulates osteoblast activity. We propose that wher e bone tissue is in direct contact with metal wire cathodes, the faradic pr oducts, hydrogen peroxide and hydroxyl ion, are significant factors which, in their own right, further contribute to accelerated remodelling and impro ved clinical outcome. (C) 1999 Academic Press.