Reports about postoperative pain in endodontics range from 3%-58% in different studies .~Pain can be provoked by mechanical, chemical, or microbiological injuries to periodontal tissues . A number of treatment related parameters have been shown to be associated with the presence of postoperative pain, including working length (WL) estimation with an apex locator connected to every file , the number of visits , the choice of instrumentation , and the choice of root canal sealer .~Sealers placed in the root canals interfere with periodontal tissues through the apical foramina, lateral canals, or leaching and can potentially affect the healing process in the periodontium. Thus, the local inflammation caused by root canal obturation materials may result in postoperative pain. The intensity of inflammatory reactions depends on a number of different factors, including the composition of the sealer .~The use of a sealer during root canal obturation is essential for success of root canal treatment. The sealer has various functions:~Attainment of impervious seal~Filler for canal irregularities and minor discrepancies between the root canal wall and core-filling material Expressed through lateral or accessory canals~Can assist in microbial control~Act as lubricant~Can have adhesive property to dentin~The evolution of newer techniques, instruments, materials, and better understanding of canal anatomy, has changed the face of endodontics completely. One concept that has emerged is the single-visit root canal therapy. Single-visit root canal treatment (RCT) has become a common practice and offers several advantages, including a reduced flare-up rate, decreased number of operative procedures, and no risk of interappointment leakage through temporary restorations.~The major consideration regarding one-appointment endodontics has been the concern about postoperative pain . Various studies have evaluated the post-endodontic pain difference between single- and multiple-visit RCT, but most studies have ruled out any significant difference in postoperative pain .~It has been suggested that bioceramic materials improve the outcome of endodontic treatment by promoting the differentiation of odontoblasts and by releasing biologically active substances . The bioceramic materials have been shown to be less cytotoxic compared with resin-based AH Plus (Dentsply Maillefer, Ballaigues, Switzerland) in vitro . However, AH Plus (FKG Dentaire SA, La Chaux-de-Fonds, Switzerland) exhibited stronger bonding capacity and higher radiopacity compared with bioceramic sealers. The clinical significance of these characteristics is still unclear. Data on the clinical behavior of bioceramic sealers are scarce and of great interest.
The aim of this randomized clinical trial was to compare the potential effects of resin-based and bio ceramic sealers on the occurrence and intensity of postoperative pain in patients with asymptomatic apical periodontitis (AAP) .