Introduction: A key failure of root canal treatment is the practitioner's inability to detect all the canals during treatment. Root canal detection aids like Cone beam computer tomography (CBCT) scans and Dental operating microscopes (DOM) are valuable aids for an endodontist. Although CBCT scans are considered the most reliable method for canal detection, they cannot be employed in all cases due to the potential risk of subjecting patients to excessive levels of radiation. Nevertheless, the usage of DOM can be a valuable tool to avoid undetected canals. Aim: To assess the diagnostic precision of dental operating microscopes in identifying the number of canals in maxillary Second Molars requiring retreatment, in contrast to CBCT scans. Materials and Methods: Thirty-five individuals with upper second molars who required retreatment were included. A pre-operative cone beam computed tomography (CBCT) scan was acquired for all patients, however, it was not presented to the practitioner who performed the access cavity. CBCT stage: Scans were randomly assigned to endodontic specialists for segmentation, and the number of canals was documented. Clinical stage: Six endodontic postgraduate researchers created access cavities, removed the old root canal filling, and documented the number of canals. The data acquired in both stages was compared. Results: There was no statistically significant difference between detected number of canals by the two methods. Conclusion: There was no significant difference between detected number of canals by CBCT and the dental operating microscope. Recommendations: It is recommended to employ a dental operating microscope for retreatment cases.