Continued apexogenesis of immature permanent incisors following trauma.

Two cases of trauma to immature teeth are described which differed significantly in their initial severity. However, both subsequently presented with continued apical root formation. In the two cases a histological examination after tooth removal confirmed continued apical development ot the traumatised immature teeth distant to their respective coronal portions. These cases highlight the resilience of the root sheath of Hertwig to trauma.