This is a case report of a 26-y.o. female patient with history of sport accident which caused in time, by recurrent misdiagnosed apical infections, the loss of tooth 22 and its buccal cortical plate. Loss resulted in impressive inesthetic alveolar defect (cca. 20x15 mm) that discouraged prosthodontic attempts to restore the edentation. Radiographs showed complete lack of the buccal cortical plate and extended circular lacuna of the palatal cortical plate, which turned the apparent buccal defect into an extended trough-and-trough crestal defect. Buccal and palatal flaps were raised, the lack of the buccal plate and the circular lacuna of the palatal plate were confirmed. A rectangular cortical block was harvested from the chin, adapted and fixed to the thin palatal bony bridge by mean of special suture loop. Graft was completed with a combination of autologous bone chips and TriCalciumPhosphate, flaps were repositioned. 4 months after, alveolar crest showed good dimensional stability and satisfactory esthetic appearance. Radiographs displayed slight resorbtion of the graft. Conclusions: 1) misdiagnosed traumatic events of upper incisors can lead to extended trough-and trough crestal defects. 2) treatment by bone grafting with autologous cortical chin blocks can be a predictable alternative to the GBR with reinforced membranes. Schlagwörter: crestal defect, autologous chin graft, TCP