Field Emission Scanning Electron Microscope Analysis of the Marginal Adaptation of Various Root Canal Sealers at the Dentin-Sealer and Sealer-Guttapercha Interfaces at Three Root Canal Levels: An In Vitro Study

Aims An in vitro evaluation of the marginal adaptation of four root canal sealer variants at the dentin-sealer and sealer gutta-percha interfaces in the coronal, middle, and apical thirds of root canals was conducted using field emission scanning electron microscope (FESEM) analysis. Materials and methods In total, 80 extracted human mandibular premolar teeth were used in this study. All teeth were decoronated to standardize the root length to 14 mm. A round bur was used to gain access into canal orifices and the working length was determined. Root canal instrumentation was performed using the crown-down technique with ProTaper Next rotary files up to size X3, along with the use of root canal irrigants. All specimens were then randomly divided into four groups, with 20 specimens per group, depending on the root canal sealer used: Group A consisted of AH Plus (Dentsply Maillefer, Ballaigues, Switzerland), Group B of MTA-Fillapex (Angelus Dental, Londrina, Brazil), Group C of Bio-C Sealer (Angelus Dental), and Group D of GuttaFlow-2 (Coltene Whaledent, Altstatten, Switzerland). All specimens were obturated with size X3 gutta-percha points uniformly coated with respective sealers in the single-cone technique and coronal access was sealed with glass ionomer cement. The specimens were incubated for seven days and then horizontally sectioned at the coronal, middle, and apical thirds of the root canals. On each sample obtained, three points were randomly chosen and both sealer-dentin and sealer gutta-percha interfaces were examined under FESEM at 1000x magnification. The marginal gaps of all four sealers at both interfaces and at three levels of root canals were measured in mu m and values were recorded, tabulated, and used for data analysis. One-way analysis of variance (ANOVA) and post hoc Bonferroni tests were used for statistical analysis. A p-value <= 0.05 was considered statistically significant. Results Compared to the sealer gutta-percha interface, AH Plus, MTA-Fillapex, and Bio-C sealers at all three levels of the root canals showed more marginal gaps at the sealer-dentin interface with a significant difference (p<0.05). However, the GuttaFlow-2 sealer showed no significant difference (P > 0.05). Conclusions The marginal adaptation of the GuttaFlow-2 sealer is superior to both dentin and gutta-percha at the coronal, middle, and apical thirds of root canals compared to other sealers used in the study.