Removal efficacy of two different root canal sealers in retrograde cavities: a micro-CT study

This study aimed to evaluate the efficiency of material removal and preparation time for AH Plus Resin (AHR) and AH Plus Bioceramic (AHB) sealers in retrograde cavities, while assessing the impact of 17% ethylenediaminetetraacetic acid (EDTA) irrigation compared to saline.

Thirty-two extracted mandibular premolars were instrumented to an apical size of 0.35 mm and randomly divided into two groups (n = 16) based on the sealer type: AHR or AHB. After one month of storage, the apical 3 mm of each specimen was resected, and retrograde cavities were prepared to a depth of 3.5 mm using ultrasonic tips under indirect vision. The cavities were irrigated with either 17% EDTA or saline, and material removal was evaluated through micro-computed tomography (micro-CT) scans conducted pre- and post-preparation. The time required for retrograde preparation was also recorded. Kruskal-Wallis and independent t-tests were performed using SPSS with a 5% significance threshold.

There was no significant difference in material removability between the two sealers or between EDTA and saline irrigation protocols (p > 0.05). However, retrograde cavity preparation with AHB required significantly more time compared to AHR (p < 0.05).

Both AHR and AHB sealers demonstrated effective removability when the retrograde cavity was prepared using ultrasonic tips, and the choice of irrigation solution did not influence cleaning efficiency. However, the extended preparation time for AHB suggests the need for additional caution and effort during its removal in retrograde cavity preparation.