Root canal sealers affect artifacts on cone-beam computed tomography images.

The purpose of this study was to evaluate the appearance of artifacts by four types of root canal filling sealers on cone-beam computed tomography (CBCT) images. Thirty standardized tooth models were given the radiopacity equivalent to human teeth, and root canal preparation was performed using WaveOne Gold. Root canal filling by a single-point method was performed using WaveOne Gold gutta-percha points and four types of root canal sealers: AH Plus (AH), CANALS (CA), BioRoot RCS (BR), and MTA Fillapex (MTA). Samples were taken by periapical radiography at 60 kV and scanned by CBCT at three tube voltages (70, 85, and 100 kV). The gray-scale values (GVs) of the periapical radiographs were measured and the aluminum equivalents were calculated. On the CBCT axial images, the artifact and dentin area GVs were measured and the rate of change in the GV (RCGV) was calculated as follows: RCGV (%) = (dentin area GV - artifact GV)/dentin area GV × 100. High-density areas with artifacts on the CBCT images were also measured. On the periapical radiographs, the aluminum equivalent was largest for AH and smallest for MTA. On the CBCT images, AH showed the largest values for both RCGV and the high-density areas, while BR and MTA showed comparable values. Correlations were found between the radiopacity on the periapical radiographs and the degree of artifacts on the CBCT images. These findings suggest that the greater the contrast in the 2D image, the higher the artifacts in the 3D image.