Balancing radiopacity and artifact generation: a quantitative evaluation of CBCT artifacts induced by resin-based restorative materials

BACKGROUND: While metal-induced artifacts in cone-beam computed tomography (CBCT) are well documented, quantitative data regarding the artifact intensity and spatial distribution of modern injectable composites compared with conventional resin-based materials are sparse. This in vitro study quantitatively evaluated and compared beam-hardening and blooming artifacts generated by various resin-based restorative materials, specifically investigating whether modern injectable composites produce different artifact profiles than conventional resins in CBCT imaging. METHODS: Ninety 3D-printed mandibular canine models with standardized distal cavities were restored using six different materials (n = 15 per group): G-ænial Anterior (GA), EQUIA Forte HT Fil (EQF), G-ænial Universal Injectable (GUI), Vittra APS Unique (VAU), Charisma Diamond ONE (CHR), and OMNICHROMA (OMN). All samples were scanned using a CS 9600 CBCT unit under identical exposure parameters (120 kV, 4.0 mA, 0.15 mm voxel size) to eliminate motion artifacts and ensure standardization. Grayscale values (GV) were measured on mesial, distal, buccal, and lingual surfaces using standardized regions of interest (ROIs) positioned adjacent to the restoration. Statistical analyses were performed using one-way ANOVA and Kruskal-Wallis tests with post-hoc corrections (α = 0.05). RESULTS: Significant differences in GV were observed on the mesial (p < 0.001), distal (p < 0.001), and buccal (p = 0.004) surfaces, whereas no significant difference was found on the lingual surface (p = 0.053). The GUI and GA groups showed the highest GV, while CHR exhibited the lowest GV across all surfaces. The highest GV were recorded on the mesial surface, not on the distal surface where the restoration was placed (p < 0.001). CONCLUSIONS: Different resin-based restorative materials produced different grayscale values and artifact patterns under standardized CBCT conditions. The high-filler injectable composite showed artifact characteristics comparable to those of high-viscosity resin-based materials, particularly on the surface opposite to the restoration. These findings suggest that material-related factors may influence CBCT artifact expression; however, because no direct chemical or elemental analysis was performed, these interpretations should be made cautiously. In clinical situations where CBCT imaging is anticipated, clinicians should consider the potential effect of restorative material radiopacity on image interpretation while balancing the diagnostic need for radiopaque restorations in conventional radiography.