RESUMO
Purpose: This study assessed the intensity of artifacts produced by 2 metal posts, 2 cements, and different exposure parameters using 2 cone-beam computed tomography (CBCT) units. Materials and Methods: The sample was composed of 20 single-rooted premolars, divided into 4 groups: Ni-Cr/zinc phosphate, Ni-Cr/resin cement, Ag-Pd/zinc phosphate, and Ag-Pd/resin cement. Samples were scanned before and after post insertion and cementation using a CS9000 3D scanner with 4 exposure parameters (85/90 kV and 6.3/10 mA) and an i-CAT scanner with 120 kV and 5 mA. The presence of artifacts was assessed subjectively by 2 observers and objectively by a trained observer using ImageJ software. The Mann-Whitney, Wilcoxon, weighted kappa, and chi-square tests were used to assess data at a 95% confidence level (α<0.05). Results: In the subjective analyses, AgPd presented more hypodense and hyperdense lines than NiCr (P<0.05), and more hypodense halos were found using i-CAT (P<0.05) than using CS9000 3D. More hypodense halos, hypodense lines, and hyperdense lines were observed at 10 mA than at 6.3 mA (P<0.05). More hypodense halos were observed at 85 kV than at 90 kV (P<0.05). CS9000 3D presented more hypodense and hyperdense lines than i-CAT (P<0.05). In the objective analyses, AgPd presented higher percentages of hyperdense and hypodense artifacts than NiCr (P<0.05). Zinc phosphate cement presented higher hyperdense artifact percentages on CS9000 3D scans (P<0.05). CS9000 3D presented higher artifact percentages than i-CAT (P<0.05). Conclusion: High-atomic-number alloys, higher tube current, and lower tube voltage may increase the artifacts present in CBCT images.
RESUMO
INTRODUCTION: This study quantitatively evaluated the type and amount of image artifacts generated by different intracanal materials in birooted teeth scanned at different exposure parameters. METHODS: The sample consisted of 15 birooted premolars. Seven different intracanal material combinations were used in each tooth one at a time: (1) roots without intracanal materials, (2) roots with gutta-percha, (3) a buccal root with gutta-percha and a lingual root with a fiberglass post, (4) a buccal root with gutta-percha and a lingual root with a metal core fiberglass post, (5) buccal and lingual roots with fiberglass posts, (6) buccal and lingual roots with metal core fiberglass posts, and (7) buccal and lingual roots with NiCr metal posts. Cone-beam computed tomographic scans were acquired using a CS 9000 unit (Carestream Dental, Atlanta, GA). An image of each tooth was captured under 5 exposure parameters: 2.5, 4, 6.3, 8, and 12 mA. The voxel size, field of view, and tube voltage were fixed at 0.076 mm, 5 × 3.75 cm, and 75 kV. We assessed each artifact quantitatively using ImageJ's threshold tool (National Institutes of Health, Bethesda, MD) to determine the hypodense and hyperdense artifact areas within 8-bit images extracted from the scans. All analyses were conducted with a 95% confidence level (α <0.05). RESULTS: The inferential analysis showed that roots filled with metal posts presented the highest amount of hypodense and hyperdense artifacts, whereas fiberglass post in both roots presented fewer artifacts. All materials presented more hypodense than hyperdense artifact formation. Overall, the low-exposure settings presented fewer artifacts and higher values of preserved dental images. CONCLUSIONS: Low-exposure protocols and fiberglass posts presented fewer image artifacts in CBCT scans.