How do imaging protocols affect the assessment of root-end fillings?

Abstract

Objectives This study investigated the impact of micro-computed tomography (micro-CT)-based voxel size on the analysis of material/dentin interface voids and thickness of different endodontic cements. Materials and Methods Following root-end resection and apical preparation, maxillary premolars were filled with mineral trioxide aggregate (MTA), Biodentine, and intermediate restorative material (IRM) ( n = 24). The samples were scanned using micro-CT (SkyScan 1272; Bruker) and the cement/dentin interface and thickness of materials were evaluated at voxel sizes of 5, 10, and 20 µm. Analysis of variance and the Tukey test were conducted, and the degree of agreement between different voxel sizes was evaluated using the Bland and Altman method ( p < 0.05). Results All materials showed an increase in thickness from 5 to 10 and 20 µm ( p < 0.05). When evaluating the interface voids, materials were similar at 5 µm ( p > 0.05), while at 10 and 20 µm Biodentine showed the lowest percentage of voids ( p < 0.05). A decrease in the interface voids was observed for MTA and IRM at 20 µm, while Biodentine showed differences among all voxel sizes ( p < 0.05). The Bland-Altman plots for comparisons among voxel sizes showed the largest deviations when comparing images between 5 and 20 µm. Conclusions Voxel size had an impact on the micro-CT evaluation of thickness and interface voids of endodontic materials. All cements exhibited an increase in thickness and a decrease in the void percentage as the voxel size increased, especially when evaluating images at 20 µm.

Marginal Adaptation and Porosity of a Novel MTA Brand Applied as Root-End Filling Material: A Micro-CT Study

“…In a recent noteworthy study, Torres et al [45] found that the evaluated cements demonstrated a decrease in the void percentage when a greater voxel size was used. These discrepancies occurred since the micro-CT images are limited by the dimensions of the target object.…”

“…Generally, this disparity may be due to the lack of standard assessment methods. In a research series, Torres et al [43][44][45] investigated the impact of various factors on the accuracy of the quantitative measurement of the porosity volume in CSCs by micro-CT, such as voxel size, image-processing software, and the radiopacity of the material. According to the authors [45], smaller voxel sizes are preferable for evaluating both the thickness of materials and the volume of interfacial voids produced by them.…”

“…In a research series, Torres et al [43][44][45] investigated the impact of various factors on the accuracy of the quantitative measurement of the porosity volume in CSCs by micro-CT, such as voxel size, image-processing software, and the radiopacity of the material. According to the authors [45], smaller voxel sizes are preferable for evaluating both the thickness of materials and the volume of interfacial voids produced by them. Moreover, the immersion period of root-end filling materials in distilled water may affect their stability, as various CSCs demonstrated volumetric changes to different extents [43].…”