Concluding remarks

Abstract

The transmission and modulation of pain from the dental pulp is a highly complex and multidimensional phenomenon which involves processing of input derived from primary nociceptors located in the dental pulp. Presently, there are a few studies which have characterized the contents of the vesicles located within nerve terminals in the predentine, odontoblastic zone and the pulp proper. These studies have been able to demonstrate whether the material in the vesicles is a catecholamine or related to acetylcholine. This was a giant step forward since prior classification had been by size of the vesicles, which varies according to the activity in the ending, or the fixative employed. A fixative such as permanganate, for example, forms a precipitate of manganese oxide at endings when noradrenaline is present. This has allowed identification of adrenergic endings with dense vesicles from cholinergic which are more electron-lucent. Recent technical advances now allow the use of monoclonal and polyclonal antibodies, made against various neurotransmitters, to be used with fixed and demineralized tissues. With these probes, the presence and location of the various types of neuronal terminals located in the dental pulp should be elucidated within the next few years. This evidence, in conjunction with the morphological and immunohistochemical evidence already available of the various neurotransmitters located in the dental pulp, i.e. VIP, substance P, calcitonin gene-related peptide, somatostatin, acetylcholine, norepinepherine, neuropeptide Y and serotonin, should enable a dual attack by anatomists/pulp biologists and physiologists to discriminate whether these neurotransmitters are excitatory or inhibitory.