Detection of lingual canal in mandibular single-rooted teeth using dental operating microscope and dental loupes: a comparative study

PURPOSE: Most of the studies on the methods used to detect extra canals are related to the second mesiobuccal canal in maxillary molars. This study aimed to evaluate the effectiveness of dental operating microscopes (DOM) and dental loupes (DL) in detecting lingual canals in extracted single-rooted mandibular teeth. The null hypothesis was that there would be no difference in lingual canal detection success between DL and DOM. MATERIALS AND METHODS: Sixty single-rooted mandibular teeth were randomly selected by using an online randomisation tool and examined using cone-beam computed tomography (CBCT), which served as the reference standard. No prior information about canal configuration was provided for blinding of the operator. Lingual canals were identified in 36% of the teeth. Access cavity inspection was performed under three conditions: direct visual inspection (DVI), a 6× magnification DL, and a DOM (1.8×-19.4×). Cohen's kappa coefficient was used to assess agreement between methods. Sensitivity, confidence intervals, and statistical comparisons were reported. RESULTS: None of the techniques detected all lingual canals. Sensitivity was 0.40 (95% CI: 0.22-0.61) for DVI, 0.59 (95% CI: 0.38-0.78) for DL, and 0.68 (95% CI: 0.46-0.85) for DOM. Both DOM and DL showed moderate agreement with CBCT (κ = 0.55 and κ = 0.51, respectively), with no statistically significant difference between them (p = 0.147). The success of DL (p = 0.031) and DOM (p = 0.005) in finding the lingual canal was statistically higher than DVI. The study demonstrated that magnification significantly improves lingual canal detection rates. CONCLUSION: While neither tool achieved perfect accuracy, the use of magnification notably enhanced the detection of lingual canals compared to direct vision. The usage of DOM and DL may improve treatment prognosis. DLs may offer a cost-effective alternative to DOMs. However, limitations such as the ex vivo nature of the study and small sample size warrant caution. Further clinical validation is needed to support generalization to in vivo settings.