Avaliação da tomografia computadorizada de feixe cônico no diagnóstico de gaps marginais em restaurações indiretas: a influência dos artefatos metálicos na qualidade da imagem

Abstract

The aim of the study was evaluating the quality of cone beam computed tomography (CBCT) images of metal-ceramic and all-ceramic crowns, before and after the cementation process, to verify the influence of artifacts on the clinical identification of marginal gaps and to compare the identification of marginal gaps observed in intraoral radiographs with those diagnosed on tomographic images. Therefore, 18 teeth restored with metal-ceramic (n = 9) and all-ceramic (n = 9) crowns, duly adapted and with gaps of 0.30 and 0.50 mm, were submitted to CBCT scans and intraoral radiographs, before and after the process of cimentation with resin cement. To analyze the quality of the CBCT images, the contrast-to-noise ratio (CNR) between the different restorative materials was calculated. In addition, four examiners evaluated the presence or absence of gaps in radiographic and tomographic examinations. For comparison of the CNR values, the Mann Whitney test was used, and for comparison of values before and after cimentation the Wilcoxon test was used. To assess the agreement of qualitative variables, the Kappa test was used. Sensitivity, specificity and accuracy values, determined by the area under the ROC curve, were calculated for each type of crown and gap size before and after cementation. No significant difference in CNR values was observed between the two crowns tested. As regards the identification of marginal gaps, low accuracy and sensitivity values could be observed for both crowns, irrespective of the gap size, cementation or image evaluated. We could conclude that the two types of materials tested interfered in the quality of the CBCT image, and that tomography did not improve the accuracy of the diagnosis of marginal gaps in indirect restorations.