Neural Control of Pulpal Blood Flow

Abstract

Blood flow of mammalian dental pulp is under both remote and local control. There is evidence for the existence of parasympathetic nerves in the pulp, but functionally the cholinergic influence is weak, and the physiological significance of this autonomic system seems to be low. The evidence for sympathetic vasoconstrictor nerves in the pulp is robust, and there is convincing support for the contention that these nerves play a physiological role, operating via release of noradrenaline and neuropeptide Y. However, there is no significant functional evidence in support of sympathetic beta-adrenoceptor-mediated vasodilation in the pulp. The local control of blood flow involves a subset of intradental sensory nerves. By virtue of their neuropeptide content, these afferent fibers cause vasodilation and inhibit sympathetic vasoconstriction in response to painful stimulation of the tooth. Such locally governed control may serve to meet immediate demands of the pulp tissue. A locally triggered reflex activation of sympathetic nerves in the pulp may modulate this control and limit its magnitude. Thus, there are competitive interactions between local and remote vascular controls which may be put out of balance in the injured and inflamed dental pulp.

An overview of the dental pulp: its functions and responses to injury

“…Pulp blood flow is hence considered to be predominantly under neural control. 63 The possible existence of a local vascular regulation in the pulp has been proposed recently. [76][77][78][79] It is important in the confined and restricted circulation that microvascular tone is modulated locally to match the nutrient flow and tissue demands.…”

“…38,[59][60][61][62] Pulp blood flow in anaesthetized animals of several species is under the influence of local nerve impulses unrelated to systemic haemodynamics. 63 Perivascular sympathetic nerve fibres liberate noradrenaline and possible neuropeptide Y causing a reduction of pulp blood flow, [64][65][66][67] whereas intradental sensory nerves liberate neuropeptides causing an increase in pulp blood flow. 50,[68][69][70][71] Reflex excitation of the sympathetic nervous system causes pulp vasoconstriction and a reduction in pulp blood flow.…”

Interstitial Fluid Pressure in Normal and Inflamed Pulp

“…These immunoreactive nerve fibers in dentin may very well represent branches of nerves terminating around the pulpal blood vessels. It has been shown that mechanical or electrical stimulation of dentin causes pulpal vasodilation and therefore increased P, in the lowcompliant dental pulp (Olgart et al, 1991;Heyeraas et al, 1994;Olgart, 1996;lacobsen and Heyeraas, 1997 dentin (Vongsavan and Matthews, 1992b). An axon reflex, like that involved in cutaneous nociceptor stimulation (Lewis, 1927), might therefore also seem possible in the pulp, and might be of functional importance in the development of vasodilation observed by stimulation of dentin as oulined in Fig.…”

Üniversal bir adezivin ER:YAG lazerle prepare edilmiş çürükten etkilenmiş dentine mikrogerilim bağlanma dayanımı

“…(Pashley 1989). Dentinin bu canlı doku özelliği nedeniyle, döner aletlerin pulpada lokal nörojenik iltihaba neden olabileceği ileri sürülmektedir (Olgart 1996). Bu sorunu gidermek için alternatif çürük temizleme teknikleri geliştirilmiştir.…”