# Evaluation of the Penetration Depth of Four Different Root Canal Sealers into Dentinal Tubules: A Scanning Electron Microscopic Study

## TL;DR

This study compares how deeply four root canal sealers penetrate dentinal tubules at different levels of a tooth using scanning electron microscopy.

## Contribution

The study provides new empirical data on the penetration depth of four specific root canal sealers in dentinal tubules.

## Key findings

- MTA Fillapex showed significantly higher dentinal tubule penetration than other sealers at all tested levels.
- Penetration depth varied significantly between the coronal, middle, and apical thirds in all groups.
- Zinc oxide eugenol (ZOE) and AH Plus had the lowest penetration depths compared to MTA Fillapex.

## Abstract

Aim

This study was designed to establish the average depth of penetration of four different root canal sealers into the dentinal tubules at the cervical, middle, and apical third levels.

Methodology

Forty-eight mandibular premolars were decoronated, and cleaning and shaping were done in a crown-down manner using ProTaper Gold (Densply Maillefer, Ballaigues, Switzerland) rotary instruments. To simulate smear layer removal in a clinical setting, all canals were then irrigated with 3 ml of 17% ethylenediaminetetraacetic acid (EDTA), i.e., SmearClear (Sybron Endo, Glendora, CA, USA) for one minute, followed by 3 ml of 3% sodium hypochlorite. Canal irrigation was performed with 5 ml of saline to get rid of excess irrigating solution. All the samples were randomised into four groups based on the sealer by a person not related to the study to ensure anonymity, as follows: Group A: Zinc oxide eugenol sealer (ZOE); Group B: AH Plus sealer (Densply Maillefer); Group C: Apexit Plus sealer (Ivoclaar vivadent, Gurugram, India); Group D: mineral trioxide aggregate (MTA) Fillapex sealer (Angelus, Torrance, CA, USA). Obturation of the samples was done using the lateral compaction, and samples were then sectioned in the bucco-lingual mode using a disc under copious irrigation using distilled water. Samples were dehydrated and gold sputtered for scanning electron microscopy (SEM) evaluation. Data was pooled and interpreted using the Mann-Whitney U test and Kruskal-Wallis test.

Results

Analysis showed a statistically significant difference with a p-value of <0.05 between the coronal third, middle third, and apical third in all the groups. In pairwise comparison, the mean depth of penetration of MTA Fillapex was much higher than that of Apexit Plus, AH Plus, and ZOE sealer at the coronal, middle third, and apical third levels.

Conclusion

Within the limitations of this in vitro SEM study, MTA Fillapex demonstrated superior dentinal tubule penetration compared with AH Plus, Apexit, and zinc oxide eugenol-based sealer.