Can smarter tools make root canal retreatments less painful?

Copied word for word from the study's registry entry, so the wording is the study team's rather than ours.

Inclusion Criteria: * Patients between 18- 65 years of ages * Patients who agree to participate this study * Patients had not used analgesic or antibiotics in last 7 days * Mandibular molar teeth that have been endodontically treated only once * Asymptomatic teeth with previous endodontic treatment but exhibiting inadequate root canal filling on radiographic examination. * Teeth, although asymptomatic, but with newly developed periapical radiolucency within two years compared to the radiographic findings present 2 years ago at the time of root canal treatment was done. * Teeth with periapical radiolucency, but with increased or unchanged according to pre-treatment radiography. * Absence of a history of allergy to local anesthetics, medications, resin-based restorative materials or nickel. Exclusion Criteria: * Pregnant patients and patients in lactation period * Having used corticosteroids in the last 6 months. * Individuals with systemic diseases (endocarditis, immune system diseases, etc.) requiring antibiotic prophylaxis * Having received immunosuppressive therapy within the last week * Gingival recession exceeding 3 mm, deep periodontal pocketing, tooth mobility, or progressive periodontal disease * The presence of a foreign body in the root canal that prevents entry (broken file, post, etc.) * Fracture or crack in the root * Teeth that cannot reach the working length due to calcification in the root canal and step formation * Teeth that cannot be restored due to excessive loss of material in the coronal structure * The presence of more than one adjacent tooth requiring endodontic treatment that may cause reflected pain in the same patient. * Teeth that develop any complications (breakage of endodontic file, perforation, inability to determine the working length with the apex finder) during the removal of the canal filling material.