<b>Comparing Treatment Outcomes Using Digital Periapical Radiographs Against Cone-Beam CT for Managing Complex Root Canal Cases</b>

Background: Accurate retreatment of failed root canal cases requires reliable identification of complex canal anatomy and persistent periapical pathology. Digital periapical radiographs are routinely used but provide limited two-dimensional information, whereas cone-beam computed tomography offers three-dimensional visualization that may improve retreatment planning. Objective: To compare clinical and radiographic outcomes of cone-beam computed tomography-guided retreatment with digital periapical radiograph-guided retreatment in previously failed root canal cases. Methods: A parallel-group randomized controlled trial was conducted among 72 adults requiring nonsurgical endodontic retreatment. Participants were allocated equally to cone-beam computed tomography-guided planning or digital periapical radiograph-guided planning. Standardized retreatment procedures were performed in both groups. Outcomes were assessed at baseline and four weeks. The primary outcome was radiographic healing measured by periapical index score, while secondary outcomes included visual analog scale pain score and tenderness to percussion. Results: Sixty-five participants completed follow-up, including 33 in the cone-beam computed tomography group and 32 in the periapical radiograph group. The cone-beam computed tomography group showed significantly lower four-week periapical index scores than the control group (1.8 ± 0.6 vs 2.4 ± 0.7; mean difference -0.6, 95% CI -0.9 to -0.3; p=0.001). Pain scores were also lower (1.9 ± 0.8 vs 2.8 ± 0.9; p=0.002), and tenderness was less frequent (15.2% vs 34.4%; p=0.048). Conclusion: Cone-beam computed tomography-guided retreatment improved short-term radiographic healing and clinical recovery compared with periapical radiograph-guided planning, supporting selective use in complex endodontic retreatment.