Influence of Tooth Orientation on the Detection of Vertical Root Fracture in Cone-beam Computed Tomography

The purpose of this study was to assess the influence of tooth orientation in relation to the projection plane of the x-rays on the detection of vertical root fracture (VRF) with different filling materials using cone-beam computed tomographic (CBCT) imaging.

Thirty single-rooted human teeth were endodontically instrumented, and VRF was induced in half of the sample. The roots were individually placed in the dental socket of a phantom head composed of a dry human skull and mandible, and CBCT images were obtained of each root with the longitudinal axis in 2 orientations: perpendicular and parallel to the projection plane of the x-rays. Also, each root was scanned under 3 filling conditions: without filling material, with gutta-percha, and with a metal post. Radiation doses at specific anatomic regions of the phantom were obtained for the 2 orientations. Five radiologists evaluated all images and rated the fractures on a 5-point scale. The sensitivity, specificity, accuracy, and positive and negative predictive values were calculated. The area under the receiver operating characteristic curve and the dosimetric outcomes for each root orientation and filling material were compared, respectively, with 2-way and 1-way analysis of variance with the post hoc Tukey test (α = 0.05).

There was no significant difference (P ≥ .05) in the detection of VRF between root orientations regardless of the filling material. Az values were significantly lower (P < .05) in the presence of gutta-percha and a metal post. The root orientation varied the absorbed dose at some anatomic regions.

The orientation of the tooth in relation to the projection plane of the x-rays does not influence the detection of VRF using CBCT imaging irrespective of the intracanal material.