10 - Management of the Vital Pulp and of Immature Teeth

Abstract

The dentin-pulp complex has very elaborate defense mechanisms mediated by trigeminal sensory neurons, odontoblasts blood vessels, and cells of the immune system. Despite being encased by enamel and cementum, the dentin-pulp complex pulp is at risk of infection and injury once the protective layer is lost by caries, trauma, or iatrogenic factors. In addition to nociception, sensory neurons participate in the early defense response to injury mediating the process of neurogenic inflammation by the release of vasoactive peptides leading to localized increased vascular flow and permeability. As response to injury, odontoblasts increase their secretory activity forming a protective layer, a process called reactionary dentinogenesis. In cases of odontoblastic layer loss, progenitor cells may be recruited from a healthy underlying pulp to the area of injury where they differentiate and secrete a mineralized layer, a process called reparative dentinogenesis. Vital pulp therapies have evolved to exploit the remarkable reparative and reactionary capacity of the dental pulp, and include indirect and direct pulp capping procedures and partial or complete pulp chamber pulpotomies. Unfortunately, insults of high intensity and duration may overwhelm the inherent pulp reparative capacity leading to necrosis. This untoward event is particularly detrimental in immature teeth with incomplete root development that may be treated with nonvital therapies such as apexification or regenerative endodontic procedures (REPs). Apexification relies in the disinfection of the root canal system and sealing of the apex by placement of a tricalcium silicate apical plug followed by the obturation of the root canal system. These procedures have excellent clinical success; however, they do not promote the continuation of root development. Alternatively, REP reply on the disinfection and apical mesenchymal stem cells to repopulate the canal space. These procedures have been shown to promote healing and continued root development. It is recognized that the tissues being formed by these procedures do not entirely recapitulate the lost native pulp; instead they represent a form of reparative tissue that includes the presence of cementum and bone. Further efforts focused on better control of the regenerative process will improve the predictability and acceptance of regenerative endodontic therapies.