Aim: To compare the 12-month radiographic outcome of root canal treatment with and without the additional use of QMix 2-in-1 (Dentsply Tulsa, Maillefer, Ballaigues, Switzerland) irrigation solution.

Methodology: The study included 60 single-rooted teeth with periapical radiolucency of 60 patients, randomized into two groups using randomized block design with block sizes of 10 patients in each. Root canals were prepared with WaveOne Gold files (Dentsply Sirona, Maillefer, Ballaigues, Switzerland) and irrigation was performed with 5 mL 2.5% sodium hypochlorite (NaOCl) using side-vented needles during instrumentation. The final irrigation protocol was performed using 5 mL 2.5% NaOCl (n= 30) or 5 ml QMix 2-in-1 (n=30). Then the root canals were irrigated with 5 mL of distilled water and filled with gutta-percha and AH Plus sealer (Dentsply Sirona), using the cold lateral compaction technique. The patients were recalled after 12 months and evaluated radiographically according to perapical index (PAI) scores. Pre and post-treatment PAI scores were compared and teeth were considered 'healthy' (PAI ≤ 2) or 'diseased' (PAI ≥ 3). The Mann Whitney U test was used to compare the differences between the post-operative and follow-up images of the treatment groups. The Wilcoxon signed rank test was applied to examine the changes in PAI score from baseline to the follow-up evaluation in each group.

This randomized controlled trial was conducted to evaluate radiographic periapical repair after endodontic treatment using QMix 2-in-1 (Dentsply Tulsa, Maillefer, Ballaigues, Switzerland) and NaOCl irrigation in single-rooted teeth with apical periodontitis.

Inclusion Criteria:

• necrotic, single root teeth with a periapical lesion (2>PAI>5)

Exclusion Criteria:

• pregnant
• had used antibiotics within the previous week
• allergy to local anesthetic agents
• history of intolerance to non-steroidal anti-inflammatory drugs
• had uncontrolled hypertension, uncontrolled diabetes mellitus, chronic renal failure, hematological disease, or had received or were receiving radiotherapy and periodontal bone loss (visualized radiographically)
• open tooth apex