Avaliação de gaps marginais e da qualidade da imagem de coroas confeccionadas em dois diferentes materiais restauradores: um estudo in vitro com imagens de TCFC

Abstract

The aim of the study was to assess the presence of marginal misfits on cone beam computed tomography (CBCT) images of teeth restored with all-ceramic and metal-ceramic crowns and compare the gap sizes observed on CBCT images with those obtained on micro computed tomography (micro-CT) images. Therefore, a total of 30 teeth restored with metal-ceramic (n = 15) and all-ceramic (n = 15) crowns, properly adapted and with gaps of 0.30 and 0.50 mm, were submitted to micro-CT and CBCT scans. Linear measurements corresponding to the marginal gap (MG) and the absolute marginal discrepancy (AMD) were obtained in the two imaging exams. The objective assessment of the quality of CBCT images was performed using the contrast-to-noise ratio (CNR). The quality of CBCT images was assessed by five examiners to verify the presence or absence of gaps. The Mann Whitney test was used to compare the MG and AMD values between the CBCT and micro-CT exams, and the RCT between the different restorative materials. Sensitivity, specificity and accuracy values, determined by the area under the ROC curve, were calculated for each crown type and gap size. Marginal mismatch values were always higher for CBCT, with a significant difference for AMD. No significant difference in image quality was observed by means of CNR, between the two crowns tested. Low accuracy and sensitivity values could be observed for both crowns, irrespective of the gap size. Whereas the specificity values were higher for metal-ceramic crowns than for crowns fabricated of all-ceramic. It can be concluded that marginal mismatch measures were overestimated in CBCT images. No difference in image quality was observed between metal-ceramic and all-ceramic crowns. The accuracy and sensitivity values were considered low, irrespective of crown type and gap size.