Micro–Computed Tomography Assessment of Apical Accessory Canal Morphologies

• 178 accessory canals (ACs) from 93 root tips were reconstructed and analyzed.
• The morphologic parameters included diameter, length, shape, and undulation.
• 8% ACs had a diameter >150 μm.
• The minimum diameter of the ACs was only 16.7 μm.
• The morphology features varied among ACs.

IntroductionThe morphologic features of accessory canals (ACs) were investigated by using micro–computed tomography technique with a centerline fitting algorithm.MethodsNinety-three 3-mm-long apical root segments with unobstructed ACs were scanned by micro–computed tomography at 2.5-μm scanning resolution. After automatic segmentation, a centerline of the reconstructed lateral canal was developed, and the diameter, length, shape, and undulation of ACs were analyzed along the centerline.ResultsOf 178 unobstructed ACs identified, the median diameter was 67.0 μm, the average length was 786.6 μm, the predominant shape was oval, and the undulation was tortuous rather than straight.ConclusionsThe diameter, length, shape, and undulation may vary among ACs in particular from the pulpal space to the external root surface, which may complicate the debridement of the ACs.