The role of dental pulp in the development of the teeth. Young patients with infected or damaged tooth pulp still present a challenge among practitioners due to the degree of tooth development, more specifically the permanent teeth that have not completed their root development. At the time of eruption, only two thirds of the tooth root is developed. If there is a disruption of pulp vitality before the full root development, the root growth and dentin formation stop, resulting in reverse-tapered or flared roots and an opened apex, which will make the future root canal treatment difficult. In these cases, we can find teeth with short roots, very thin walls and an inadequate crown-root ratio. The thing root walls increase the risk of fracture. We currently have several therapies available to treat these teeth, which we will discuss further on.