The Physiological Aspects of the Piezoelectric Phenomenon and its Application in Biologic Bone
The relationship between stress and bony architecture has long been recognized, but the actual cellular machanism which causes the alteration is still somewhat vague. Piezoelectric properties and bioelectric potentials have been proposed as partial answers. It is the purpose of this investigation to better understand and correlate the relationship of electric potentials or bioelectric potentials to the formation and transformation of physiologic bone. It is very likely that the crystallites of bone possess the physical properties that would allow them to exhibit the piezoelectric phenomenon. In the technique of this work a direct current and a pulsating current across the femur shafts of growing dogs were applied for three weeks. The currents ranged from two to sixty microamperes. The results obtained were in discord with previous literature in that adverse effects to direct current were observed in all cases at the positive poles. Previous literature has claimed osseous growth at both poles. especially the negative pole. These results are explained in the nature of the electrical field that is produced from a direct current. The field acts to depolarize the ions in the area. This results in the migration of positive ions away from the positive pole. Such ions of bone as Ca++, K+, Na++ and Mg+ are driven away from this area and result in a breakdown in the inorganic or mineral ultrastructure of the bone. The conclusions of this thesis are: 1. Direct current adversely effects bone growth. 2. Demineralization occurs at the positive poles. 3. Bony dissolution and necrosis ensues following demineralization. 4. Trauma results in Osseous callus growth with increased mineralization of the area affected.
Orthodontics and Orthodontology, Bone and Bones
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