The goal of this clinical trial is to primary purpose investigate and compare oxidative stress markers in patients with chronic apical periodontitis treated with different root canal paste in a single session. The main questions it aims to answer are: Is there a change in oxidative stress markers measured from saliva after root canal treatment? Is there a difference between the change of oxidative stress markers in patients using different root canal sealers after root canal treatment? Researchers will compare bioceramic-based and epoxy resin-based root canal sealers to see if there are significant differences in oxidative stress markers measured from patients' saliva after root canal treatment. * Participants will be informed about all procedures before starting the clinical process. * Participants are expected to allow saliva sampling two times: first sample will be collected on root canal treatment session and second sample will be collected on the 30th day after root canal treatment. * Participants will be informed in writing about the treatment procedure before starting the clinical process. * Participants are expected to sign the informed consent form on a voluntary basis.