Preoperative Estimation of Endodontic Working Length With Cone-Beam Computed Tomography and Standardized Paralleling Technique in Comparison to Its Real Length: an in Vitro Study.

Abstract

Background: An accurate estimation of the working canal length is essential for successful root canal treatment. This study aimed to investigate the diagnostic accuracy of root canal length estimation on cone-beam computed tomography (CBCT) scans and digital paralleling radiographs (PAs), using the real canal length as a gold standard, and to evaluate the influence of canal curvature on this estimation. Methods: Sixty extracted human premolar teeth selected for this study. Root canal length measurement performed on CBCT scans (NewTom, Giano, Verona, Italy) and digital paralleling radiography (EzRay Air W; Vatech, Korea). The real working length established by subtracting 0.5 mm from the actual canal length. Results: No significant difference was found between CBCT and digital paralleling radiography. There was a tendency for underestimation of the root canal length measured on the CBCT images in 52 (86.7%) of the examined teeth and overestimated it in 5 teeth (8.3%). All the digital radiographs slightly overestimated the real canal length. The analysis revealed a strong correlation between the estimation from moderate to severe curvature for digital radiography, and CBCT images. Conclusion: Preoperative working length estimation can be made closest to its real clinical canal length on the standardized paralleling technique, using a long (16-inch) target–receptor distance.