Um modelo físico baseado nas teorias de Maxwell e Wagner foi desenvolvido para o comportamento elétrico do osso conduzindo a uma "fórmula de mistura" adequada à simetria cilíndrica. O osso foi considerado um dielétrico heterogêneo constituído de colágeno, mineral e fluido e investigado no estado seco. Capacitância e fator de perda foram experimentalmente determinados a 10 freqUências na faixa. entre 100 Hz e 4 MHz em amostras de osso bovino transformadas em capacitores de placas pa raleIas. Os resultados demonstraram que o modelo é váli do não somente para o cálculo das propriedades do compos to como também para a quantificação das propriedades das fases, conhecidas as frações volumétricas e organização estrutural.

Stress generated potentials (SGP) on bone and its relationship with bone growth and remodeling have been a subjeet of investigation during the last years. Interest in studying the eleetrieal behavior of this tissue has, as a eonsequenee, grown up. The present researeh involved experimental studies of the dielectrie properties of samples of bovine mature bone together with development of a physieal model whieh eonsiders bone as a composite of eollagen, mineral and fluido Taking in to consideration bone's ultrastrueture and eomposition, a MaxwellWagner model leading to a eonvenient mixture formula was proposed. Data were obtained from deeollagenized and demineralized bone speeimens so prepared as to serve as dieleetries of parallel plate eapaeitors. Capacitance and loss faetors were measured in the 100 Hz to 4 MHz frequency range, providing information about relative eleetrieal permittivity and dieleetric loss. These figures were subsequently used with the model equations in order to obtain dieleetric properties of hidroxyapatite and eollagen. The mixture formula was then used to calculate the dieleetrie properties of "dry" bone. Theoretieal results were eompared to experimental data obtained from integral bone specimens whose eleetrieal properties were also measured within the same frequeney range. The model equations provided eleetrieal permittivity and dieleetrie loss figures at discrete frequeneies whieh were elose to the experimental data. As an extension to the theory, Debye's equation ean be used in order to predlet the dieleetric behavior of both dry or wet bone in an extended frequency range.