## 4 Discussion
Moreover, the Ca\({}^{2+}\) silicate produces Ca\({}^{2+}\) silicate hydrate gel and Ca\({}^{2+}\) aluminate hydrate gel by absorbing the moisture from all the surrounding tissues in the root canal system and some crystallization of Ca\({}^{2+}\) hydroxide according to the manufacturer. All these factors may contribute to CeraSeal sealer's increased viscosity and decreased flowability. Currently, it is well understood that the differences in the format, filler content, and/or thickening agents may cause differences in physical and chemical properties as well [45]. Hence, its samples showed the highest number of leakages in our study. Several factors, including the physical properties of the materials (such as film thickness, wettability, and flowability), the anatomical variations of the root canal system, and the obturation technique, might affect the degree of microleakage [46, 47]. The obturation techniques used in this study were the single-cone technique with the bio-ceramic sealers and the lateral condensation technique with the AH Plus sealer. Bio-ceramic sealers are advised to be used with a heat-free obturation technique to avoid them hardening quickly. This was tested by [PERSON] et al. who used a modified obturation technique with bio-ceramic sealers and revealed that a greater penetration into the dental tubules is associated with the non-heating of the apical area using this new technique [48]. Neither technique can provide obturation free of voids [49]. [PERSON] et al. [50] recommended the usage of bio-ceramic sealers with a single-cone technique due to the slow setting time of the bio-ceramic sealers, which may allow more time for expansion, hence pushing the sealer toward the dentinal walls of the root. That may accentuate the single cone obturation technique's superior sealability. This was confirmed by SEM results of the adaptation of AH Plus sealer to the root canal wall. More studies [51, 52] found that bio-ceramic sealers ended up with smaller gaps than epoxy resin-based sealers. Hydrophilicity, insolubility, and unshrinkable nature in oral fluids can help in producing fewer and smaller gaps with bio-ceramic sealers. The inherent compositional properties of bio-ceramic sealers produce Ca\({}^{2+}\) hydroxide and hydroxyapatite, guaranteeing an outstanding bond between the sealer and both the dentin walls and the filling material. The AH Plus sealer, however, achieved the highest bonding strength results with cold lateral compaction compared with the single-cone technique [53]. This may be explained by the pressure provided by the spreaders over the master and accessory cones. It can create lateral and apical forces and can help the sealer interlock with the dentinal tubules and/or irregularities. On the other hand, the single-cone technique generates mainly apical forces. This was confirmed by SEM results with the least adaptation of CeraSeal sealer to the root canal wall. [PERSON] et al. [54] stated that regardless of the kinds of sealer or obturation techniques used, the penetration of dentinal tubules of the root canal increased in the apico-coronal direction due to the increased removal of the smear layer in the upper-middle part of the root canal. In fact, the degree of sealer adhesion to the dentinal walls depends on the dentin surface energy, surface tension and wettability of the sealer, and the cleanliness of the dentin surface. Hence, the different results in our study may be due to the different materials, different obturation techniques, or the anatomical variations of the root samples used. Future studies should include larger samples and reproducible methodologies to ensure the same results.