FESEM Analysis of Dentin Cleanliness and Erosion at the Apical Third Level after Treatment with Five Irrigating Solutions: An in vitro Study

For root canal therapy to be successful, thorough debridement and shaping of the root canal system are essential prerequisites. It is understood that removing the smear layer before obturation (filling the canal) can significantly enhance treatment quality. This investigation aimed to assess the efficacy of five distinct irrigating solutions in clearing the smear layer, specifically from the apical one-third of the root canal.

This in-vitro laboratory study, which utilized Field Emission Scanning Electron Microscopy (FESEM), examined five different solutions: 37% orthophosphoric acid, 12% nitric acid, 42% citric acid, 17% EDTA, and MTAD, a specialized irrigant containing citric acid, an antibiotic, and a surfactant. These solutions were applied to the prepared canals of ninety-six extracted teeth (15 experimental groups and one control group) for 1, 3, or 5 minutes. Following the irrigation period, the tooth specimens were prepared for FESEM analysis. The collected data were then subjected to statistical evaluation using the Mann-Whitney test.

A statistically notable difference, in terms of both smear layer removal and dentinal erosion, was observed in the specimens treated with 37% orthophosphoric acid, 12% nitric acid, and MTAD. In contrast, the other solutions tested did not produce results that were significantly different from the control group.

The findings from our research indicate that certain irrigation solutions have a statistically significant effect on smear layer removal when compared to the controls, though this impact was only apparent after a five-minute application period. It is important to highlight, however, that under the experimental conditions of this study, neither 17% EDTA nor 42% citric acid led to any meaningful improvement in smear layer elimination.

Theseresultsunderscore the complex behavior and inconsistent effectiveness of these particular agents, highlight the need for further research to determine the optimal conditions for their application.