Background and Aim: Coronal seal is as important as the quality of root canal therapy in treatment success. This study aimed to compare the coronal microleakage of canals filled with Resilon and gutta percha with a glass ionomer coronal barrier . Materials and Methods: In this experimental study, the crowns of 64 single-rooted human premolar teeth were cut at the level of CEJ. Root canals were prepared using rotary ProTaper files. The teeth were randomly divided into 4 experimental groups (n=14) and 2 positive and negative control groups (n=8). Root canals of experimental group specimens were filled with gutta percha (groups 1 and 2) or Resilon (groups 3 and 4) using lateral condensation technique. The roots of negative control specimens...