Concluding remarks

Abstract

When reading the two previous chapters one is struck by the growing number of putative mediators of blood flow regulation in the pulp. The concept that pain fibres have a ‘motor’ function may seem strange to many of us. Nevertheless, they can bring about powerful vascular effects when activated, mainly in connection with a painful and/or noxious stimulation of the tooth. It is therefore of particular interest that tachykinin/CGRP-immunoreactive fibres are present in the pulp-dentine border as shown by Drs Akai and Wakisaka. This finding indicates that not only A-fibres but also C-fibres are located in a position to receive information from external stimuli affecting the dentine and odontoblasts. This strategic position of C-fibre nerve endings may explain previous observations that stress forces applied to a cat tooth, causing mechanical deformation of dentine, result in prompt vasodilation in the pulp (Olgart et al., 1988) similar to that seen when electrical pulses are delivered to the sensory nerves or the tooth crown. So far, most evidence shows that motor effects exerted by the sensory nerves are induced by external stimuli. However, there are indications (Olgart and Gazelius, 1988) that the sensory peptides are intermittently released in the pulp, i.e. without any obvious insult. Thus, it is possible that the tachykinins exert a continuous influence on pulpal vessels and interact with other regulatory systems in maintaining an appropriate haemodynamic function during ‘normal’ conditions.