Objective: To explore the application of cone-beam computed tomography (CBCT) combined with microscopic root canal technique in the detection of root canals and the evaluation of therapeutic efficacy in elderly patients with maxillary second molars.Methods: A total of 108 elderly patients requiring root canal therapy for maxillary second molars were divided into a control group and an observation group based on different intervention methods, with 54 cases in each group. The control group received panoramic radiography (PAN) combined with conventional root canal therapy, while the observation group was treated with CBCT combined with microscopic root canal therapy. Preoperative diagnosis results, postoperative evaluation results of PAN and CBCT, and therapeutic effects of the two groups were compared.Results: In the observation group, the detection rate of the second mesial canal on the buccal side (MB2) by CBCT was significantly higher than that by PAN (P<0.05). There was a statistically significant difference between the two methods in judging root filling quality (P<0.05), as well as in evaluating periapical healing (P<0.05). The total incidence rate of intraoperative complications and the postoperative pain visual analog scale (VAS) scores in the observation group were lower than those in the control group (P<0.05), and the clinical success rate was higher than that in the control group (P<0.05).Conclusion: The combination of CBCT and microscopic root canal technique can enhance the detection of root canals and the treatment success rate for elderly maxillary second molars, while providing an objective evaluation of therapeutic efficacy.