This is a case report of a 46-y.o. male patient with a history of a sport accident, which resulted in the injury of the upper central incisors. Patient presented years later with localized periodontitis of 11. 9 mm periodontal pocket on the distal and buccal aspect of the root, exudate, root discoloration, mobility of 11 were noticed. Radiographs revealed lacuna on the mid third of the root and 6mm mesial angular defect as measured on radiograph. Vitality tested negative. Root-canal treatment (ProTaper® + Thermafill®plus-Dentsply-Maillefer) was performed. As the attempts to electrometrically assess the root-canal length were inconclusive, a communication of the canal with the exterior was suspected. A full-thickness-flap of the anterior maxillary region was raised. An extensive external resorbtion of the root surface of 11, a deep mesial two-wall defect and lack of the buccal cortical were found. Cavity was filled with glass-ionomer cement, the defect debrided and treated by EMPs (Emdogain®-Straumann) plus bioresorbable membrane. After 18 months pocket reduced to 3 mm, with radiographic defect fill 80%. Conclusions: 1) external root resorbtions can be related to early alveolar injuries. 2) overlooked alveolar injuries can lead to penetrating external root resorbtions complicated with root caries, pulpal necrosis and periodontal defects. 3) therapeutical success can be achieved by combining conservative-endodontic-periodontal procedures Schlagwörter: root resorbtion, trauma, endodontic-periodontal lesion