Objectives : This study evaluates the effectiveness of a new bioceramic material,Root Repair Material(RRM).A material marketed as a root end filling material in apical surgery.Results of this study will allow comparison between the usefulness of this material with conventional mineral trioxide aggregate(MTA),in this specific purpose.Apical surgeries will be performed with standardized microsurgery techniques,but different materials will be used as the root end filling material.The healing of lesions and signs of inflammation will be evaluated.The null hypothesis is “there is no significant difference between Root Repair Material and MTA in terms of radiographic healing and periapical tissue responses".