Voids and marginal gaps in oval-shaped root canals filled with calcium silicate-based sealers: Micro-CT study

This study investigated the percentage of voids and marginal gaps in oval root canals filled with pre-mixed or powder-liquid calcium silicate-based sealers, using the single-cone technique. Eighty-four mandibular anterior teeth with oval root canals were selected and prepared by Reciproc R25 instruments. Teeth were then divided into two groups based on the sealer: Pre-mixed (BCS, Bio-C Sealer) (n=42) or Manipulated (BRR, BioRoot RCS) (n=42). Microcomputed tomography (micro-CT) was used to evaluate the percentage of voids and marginal gaps in the apical, middle, and cervical thirds of the root canals. Surface morphology of each sealer was evaluated on bovine dentin discs by scanning electron microscopy (SEM). Mann-Whitney and Friedman tests were employed for statistical analysis (α=5). BCS presented lower percentages of marginal gaps (p=0.00) and overall empty spaces (voids + gaps, p=0.01) compared to BRR. While BRR exhibited the lowest percentage of marginal gaps in the cervical third (p=0.00), BCS showed consistent performance across all root thirds (p>0.05). SEM showed that BCS has a homogeneous structure and compact structure, while BRR exhibits a more porous surface with a greater number of mostly micron-sized or larger voids. BCS exhibited superior filling ability in oval root canals compared to BRR. The BRR group showed the highest percentage of gaps in the middle and apical segments.