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.

• The epithelial root sheath of Hertwig is necessary for root growth
• Although usually sensitive to trauma the epithlial root sheath of Hertwig may survive significant insult
• Tooth apex development may occur separate from the coronal tooth portion if the root sheath remains viable
• Regular, long-term clinical and radiographic review is advocated for all trauma cases.