 The primary objective is to evaluate: clinical and radiographic outcome of root canal treatment at two years when using PA0903 as an endodontic sealer with gutta-percha. The success rate is defined as no pain score of 0 at the VAS scale and absence or decrease in the size of LEO fulfilment of Strindbergs criteria. If a pre-existing lesion, the size decrease associated with normal contours, width and structure of the periodontal margines is considered as success. All cases in which lesion increases or is stabilized after 2 years were judged as unsuccessful . Moreover, all cases in which Strindbergs criteria if they are suitable were not fulfilled were judged as unsuccessful. A follow-up of two years is described as the predictive time of success. 