Post-operative pain has a multi-factorial aetiology and a potential pathogenic link to the acute inflammation of the periapical area, secondary to localized chemical, mechanical, host and/or microbial damage occurring during endodontic treatment.

Postoperative pain is a usual and unpredictable outcome of endodontic treatment. Postoperative pain after RCT has been reported from 1.9%- 48%. Apical extrusion of debris (AED) or excessive apical region preparation are typically the causes of post-operative pain associated with RCT.Incomplete pulp removal, apical extrusion of the obturating material, chemical irritation, root fracture, and incorrect filling adjustment are other reasons for postoperative pain. Traditionally, gutta-percha combined with an endodontic sealer is used to fill root canal systems that need to be treated. Although these sealers are intended to be used inside the root canal during endodontic therapy, they may leach, lateral canal, or get into close contact with the periapical tissues.Sealers placed in the root canal may interfere with periodontal tissues through the apical foramen, lateral canals and can possibly affect the healing process in the periodontium. The severity of  inflammatory reactions is influenced by a variety of factors including the root canal sealers composition. In addition to this,root canal sealer might activate the trigeminal nociceptors invitro and this activation along with immunologic response may trigger pain symptoms and can cause flare up