The identification of prognostic factors which influence the long-term results of dental retransplantation and autotransplantation is one of the main aims of clinical research whose principal scope is remove or alter those factors which have a negative influence on outcome, and to identify the causes of failure and areas for improvement. The paper reports the most significant results of a clinical survey which was carried out on 135 patients who had undergone retransplantation and/or autotransplantation and were then followed for 8 years.