Operating microscope improves ability to locate and negotiate second canal in mandibular incisors

Objective: The purpose of this study was to locate and negotiate second canal in mandibular incisors with/without magnification and to characterize the lingual canals with regard to prevalence locate and negotiability. Materials and methods: Mixed populations of 50 human first and second incisors were mounted in acrylic dento-form blocks. Conventional access cavities were completed without operation microscope, while attempting to locate and subsequently negotiate the second canals. The teeth in which second canal was not located or could not be negotiated were then submitted under Operating Microscope. The results (present/absent) were recorded. Results: A total of 50 teeth, 15 of which were detected in a second canal (30%). Without OM, second canal was located in 3 teeth (20%) in the 15 teeth with second canal, but we were not able to negotiate in 2 teeth (13.3%) located. With OM, 8 (53.3%) additional second canals were located and 8 (53.3%) additional second canal were negotiated of those 15 teeth. Conclusion: Operating microscope remarkably improves location and negotiation of second canals in mandibular incisors.