Impact of the Root Canal Taper on the Apical Adaptability of Sealers used in a Single-cone Technique: A Micro-computed Tomography Study.

Aim: The purpose of this study was to assess the influence of root canal taper on the apical adaptability of three root canal sealers used in a single-cone technique by measuring void's volume.
Materials and Methods: Thirty-six maxillary premolar root canals were divided into two groups. Eighteen root canals were shaped with iRace/FKG 0.3 to 0.04 instrument and 18 with 0.3 to 0.06 iRace/FKG instrument. Roots were then scanned using micro-computed tomography (CT). Each group was divided into three subgroups, containing six samples each, filled respectively, with AHPlus® (AH), TotalFill® (TF), and a novel bioceramic (NB) sealers. The roots were rescanned using micro-CT in order to superimpose the two scans and calculate the voids volume in the apical third. Statistical analyses were done using analysis of variance (ANOVA) test with a level of significance (p < 0.05). AH4 is for the 4% tapered root canals that are filled with AH sealer. TF4 is for the 4% tapered root canals that are filled with TF. NB4 is for the 4% tapered root canals that are filled with the NB sealer. AH6 is for the 6% tapered root canals that are filled with AH. TF6 is for the 6% tapered root canals that are filled with TF. NB6 is for the 6% tapered root canals that are filled with the NB sealer.
Results: Regarding void's volume measurements, all groups filled with AH and TF sealers showed similar results for both tapers with no statistical differences (p > 0.05); 4% AH: 0.0354 ± 0.0354; 4% TF: 0.0370 ± 0.0245; 6% AH: 0.0447 ± 0.0348; 6% TF: 0.0588 ± 0.0150 (p > 0.05), whereas 6% tapered preparations showed significantly less voids compared with 4%, specifically for the NB sealer tested. 4%: 0.123 ± 0.130; 6%: 0.068 ± 0.035 (p < 0.05).
Conclusion: Bioceramic (BC) sealers showed good all-round performance demonstrating good adaptability, and reduced voids while maintaining similar characteristics when compared with conventional resin sealer.
Clinical Significance: The conservative preparations in AH4 and TF4 did not induce less voids compared with more enlarged tapers (6%) in AH6 and TF4 groups.