ENDOGENOUS VASOACTIVE SUBSTANCES AND OXYGEN-DERIVED FREE-RADICALS IN PULPAL HEMODYNAMICS

An adequate blood supply to the dental pulp is essential to the health of the tooth. A recent concept is that repeated stimulation of sensit ive teeth may induce pulpal changes; this could occur through inductio n of neurogenic inflammation and alteration of pulpal blood flow. One possibility is that production of oxygen-derived free radicals at site s of inflammation contributes to alterations in local blood flow. The first target of free radicals, generated in several pathological proce sses, is the Vascular system (essentially the endothelium). Although t he exact mechanism by which free radicals induce changes in vascular c onductance is still uncertain, they may act directly on vascular smoot h muscle or modify vascular tone by interacting with the production an d/or biological activity of endogenous vasoactive mediators. Recent da ta indicate that the oxygen-derived, free radical-generating system ca n decrease pulpal blood flow in the dog via endothelial dysfunction wh en applied locally in deep dentinal cavities. In addition to the part played by oxygen-derived free radicals, the measurement of pulpal bloo d flow and the effects of endogenous vasoactive substances on flow are discussed.