Volume of Voids in Retrograde Filling: Comparison between Calcium Silicate Cement Alone and Combined with a Calcium Silicate-based Sealer

Introduction: The aim of this study was to compare the volume of voids between retrograde filling using calcium silicate cement alone and retrograde filling using a combination of calcium silicate cement with a calcium silicate-based sealer. Methods: Twenty single-rooted, extracted human teeth were instrumented with nickel-titanium files and obturated with gutta-percha. We resected the roots at a point 3 mm from the apex, prepared the root ends, and filled the root-end cavities with Endocem Zr (Maruchi, Wonju, Korea) or Endoseal MTA (Maruchi) plus Endocem Zr. Then, we scanned the prepared samples using micro-computed tomographic imaging and performed 3-dimensional reconstruction. The percentage volume of the gap between the canal wall and root-end filling was calculated along with the percentage volume of voids in the filling materials. All data were analyzed using the Mann-Whitney U test. Selected specimens were further observed using scanning electron microscopy. Results: There were no significant differences in the percentage volumes of the gaps and internal voids between the 2 groups. Both calcium silicate and the calcium silicate-based sealer exhibited good adaptation to the cavity wall. Conclusions: The findings of our micro-computed tomographic and scanning electron microscopic analyses suggested that the volume of voids in retrograde filling using a combination of calcium silicate cement and calcium silicate-based sealer was comparable with that in retrograde filling using calcium silicate cement only. Calcium silicate-based sealers could be used in retrograde filling for clinical convenience without harmful effects on the quality of filling.