Evaluation of marginal and internal integrity of endo-crowns with different cavity depths using two chairside CAD/CAM systems

Abstract

The purpose of this study was to evaluate marginal and internal integrity of endo-crowns with different cavity depths using two different CAD/CAM systems (CEREC AC and E4D) by comparing micro-computed tomography (micro-CT).Endo-crowns (n=48) of two different cavity depth (2mm and 4mm) were fabricated in two different CAD/CAM systems (CEREC AC and E4D). The micro-CT scan was taken before and after cementation. For analysis of the marginal and internal gap, reference points were selected in 2-dimensional (2D) views of three bucco-lingual cross sections and three mesio-distal cross sections. Cross sections were examined with a microscope, SEM and ss-OCT. For calculating the total gap volume, the micro-CT sections were reconstructed 3-dimensionally (3D), and changes of volume and surface area were examined. Statistical analysis was performed using two-way ANOVA with bonferroni correction.Gap thickness increased depending on cavity depth. Gaps on the pulpal floor were largest among other sites. Gaps on the B, L margins were larger than gaps on the M, D margins. Cementation did not show significant differences in total gap thickness. Both chairside CAD/CAM systems showed similar integrities in endo-crown.Based on the present study, cementation did not increase the dimension of gap between the restoration and cavity wall. Also Cerec AC and E4D in the fabrication of endo-crown fail to show the differences. The gap on the pulpal floor seemed to affect to these results.