Comparative Evaluation of Apical Microleakage of Endodontic Sealers Using Scanning Electron Microscopy: An Ex Vivo Study

Abstract

Introduction: Achieving a hermetic apical seal is a critical determinant of long-term success in endodontic therapy, as inadequate sealing permits microleakage and subsequent periapical pathology. Despite advances in obturation materials, complete sealing of the root canal system remains a challenge. Endodontic sealers play a vital role in filling irregularities and minimizing apical leakage. Therefore, evaluating the sealing ability of various commonly used sealers is essential for improving clinical outcomes.

Objective

The present ex vivo study aimed to comparatively evaluate the apical microleakage of four commonly used endodontic sealers using scanning electron microscopy (SEM).

Materials and Methods

Eighty freshly extracted human permanent mandibular first premolars with single straight canals were selected for the study. Standardized biomechanical preparation was performed for all specimens. The samples were randomly divided into four groups (n = 20) based on the sealer used: zinc oxide eugenol, calcium hydroxide–based sealer (Apexit), GuttaFlow 2, and GuttaFlow Bioseal. All canals were obturated using the lateral compaction technique, and the access cavities were sealed with glass ionomer cement. The external root surfaces were coated with nail varnish, leaving the apical 2 mm exposed, and the specimens were immersed in 1% methylene blue dye for 72 hours. After longitudinal sectioning, apical microleakage was evaluated under SEM at 500× magnification and measured in micrometers. Statistical analysis was performed using one-way ANOVA, Tukey’s post hoc test, and Chi-square test.

Results

The results demonstrated statistically significant differences among the four groups (p < 0.05). GuttaFlow Bioseal exhibited the least apical microleakage, followed by GuttaFlow 2 and Apexit, whereas zinc oxide eugenol showed the highest microleakage values.

Conclusion

Within the limitations of the present study, bioceramic-based sealers demonstrated superior apical sealing ability compared to conventional sealers, suggesting their potential advantage in achieving a more effective apical seal in endodontic therapy.