Effect of Pulpal Base, Restorative Material and Preparation Type on Marginal and Internal Fit and Fracture Strength of Endocrowns

The aim of this study was to investigate the effect of base material, restorative material and finish line on marginal and internal fit and fracture strength (FS) of endocrowns (N = 64). The restorative materials were ceramic and hybrid ceramic, the preparations were ferrule and modified butt joint (BJ) with two grooves, and the bases were with and without fiber ribbon. Marginal and internal fit were assessed using the triple scan. Statistical analyses were performed using three-way ANOVA. The absolute marginal discrepancy (AMD), marginal discrepancy and overall fit values obtained for ceramic were 127 µm, 108 µm and 120 µm, whereas those obtained for hybrid ceramic were 139 µm, 116 µm and 130 µm, respectively (p < 0.05). The overall FS obtained for ceramic was 662 N, whereas that for hybrid ceramic was 903 N (p < 0.001). When the material was evaluated regardless of preparation and base, ceramic and hybrid ceramic exceeded the selected clinical acceptability threshold for AMD, but did not exceed it for other parameters. Hybrid ceramic restorations with ferrules and fiber bases tended to provide the highest FS, whereas ceramic restorations with modified BJs and without fiber bases tended to provide the lowest FS.