Comparison of Post-operative Pain in Relation to Working Length Assessment by Electronic Apex Locator and Digital Radiography in Permanent Teeth Among Pediatric Patients

Sample Size and Participants The sample size was calculated based on a previous study by Guzel et al. [16], which assessed post-operative pain in relation to different working length determination methods. To detect a 10% difference in mean pain scores with 95% confidence and 80% power, a minimum sample of 124 participants was required. Accounting for a 5-10% attrition rate, the final sample size was increased to 130 (65 in each group).

Inclusion Criteria Children aged 10-15 years. Clinical and radiographic diagnosis of irreversible pulpitis. Absence of systemic disease. Permanent first molars with mature apices. No radiographic evidence of root resorption or periodontal bone loss. Written consent from a parent or legal guardian. Exclusion Criteria Medically compromised or psychologically unfit children. Teeth with periapical lesions on radiographs. Teeth with severely curved or calcified canals. Presence of acute or chronic systemic inflammatory conditions. Randomization and Blinding

Participants were randomly allocated into two groups using the coin-flip method:

EAL group: Working length determination using EAL DR group: Working length determination using DR The participants and the investigator of post-operative pain were blinded to the group allocation. All clinical procedures were carried out by a single experienced endodontist who was not involved in pain assessment.

Clinical Procedure All root canal treatments were completed in a single visit under local anesthesia using 2% lignocaine with 1:80,000 epinephrine. Caries excavation and access cavity preparation were performed using sterilized high- and low-speed burs. Patency was confirmed using a #10 K-file.