Hemodynamic Deformation of Alveolar Socket Walls

Simultaneous recording of carotid arterial pressure and relative displacement of alve-olar socket walls in dogs indicates a direct relationship between hemodynamic force and alveolar wall displacement. The effect was enhanced by the administration of ephedrine and diminished by histamine. Investigations into the nature of the electro-mechanical relationship between the tooth and its surrounding alveolar bone, both in vitro1 and in vivo,2 have resulted in a corre-lation of electric polarity and the cellular re-sponses known to occur during orthodontic tooth movement. In these studies, "tipping" forces were applied to the crowns of teeth. The amplitude and polarity of the resultant charge separation (voltage or potential dif-ferences) were recorded from a variety of sites and a "charge-polarity map " was ob-tained. Areas that have been described as characterized by osteoblastic activity were routinely electronegative. Conversely, areas of positivity or electric neutrality were ob-served in regions characterized by osteocla-sia. These correlations were consistent with previous studies in long bones.3-6 Stress-induced electric charge separation is known to occur in a variety of connective tissues, including bone, cartilage, tendon, dentin, and cementum, and has been stud-ied by numerous investigators.7-12 Some of the obvious mechanical functions likely to deform connective tissue structures within the dental alveolar complex are mastication, deglutition, and speech. The hemodynamic activity of the cardiovascular system also might be a source of deformation in living bone. To study this latter factor, the relativ