Determination of Root Canal Length Up to Perforation Area Using Different Electronic Apex Locators and CBCT Images Obtained at Different Voxel Sizes: A Comparative Ex Vivo Study.

Objective: To compare the accuracy of electronic apex locators in the presence of blood and CBCT images obtained with two different voxel sizes (0.125 mm and 0.25 mm) in determining root canal length up to the perforation area.

Methods: Forty extracted, single-rooted human teeth were selected and an artificial root perforation (0.4 ± 0.1 or 1.0 ± 0.2 mm diameter) was created in the middle third of the root. The actual root canal length up to the perforation area was determined under a stereomicroscope. CBCT images were obtained with a voxel size of 0.125 mm and 0.25 mm. The root canal length up to the perforation area was measured on CBCT images and recorded as the radiographic length. The teeth were embedded in alginate and root canal length up to the perforation area was measured using two different EALs (DentaPort ZX [Morita, Tokyo, Japan] and Gold Reciproc motor [VDW, Munich, Germany]) and recorded as the electronic length.

Results: In teeth with an artificial root perforation 0.4 mm in diameter, the measurements obtained with DentaPort ZX were more accurate than with the Gold Reciproc motor (P ˂ 0.05), and on CBCT images, more accurate measurements were obtained with a voxel size of 0.125 mm compared to 0.25 mm (P ˂ 0.05). In teeth with an artificial root perforation 1.0 mm in diameter, the radiographic length was closer to actual length than the electronic length (P ˂ 0.05).

Conclusion: In artificial root perforations with a diameter of 0.4 mm, CBCT gives more reliable results than EALs. Both EAL and CBCT measurements were closer to actual length in artificial perforations that were 1.0 mm in diameter.