Root Canal Transportation and Centering Ability of Nickel-Titanium Rotary Instruments in Mandibular Premolars Assessed Using Cone-Beam Computed Tomography

Fig. (1) Cross-sectional image illustrating canal area measurements. M1 = shortest distance between mesial aspect of root and mesial portion of non-instrumented canal; M2 = shortest distance between mesial aspect of root and mesial portion of instrumented canal; D1 = shortest distance between distal aspect of root and distal portion of non-instrumented canal; D2 = shortest distance between distal aspect of root and distal portion of instrumented canal.