Impact of radiation therapy regimen on the dislodgement resistance of endodontic sealers: A micro push-out test

Abstract

Purpose

This study aimed to assess the impact of the radiation therapy regimen on the dislodgement resistance of endodontic sealers of different bases through a micro push-out test.

Materials and methods

Dentin slices were obtained from the cervical and middle root thirds of bovine incisors and distributed into three groups, according to the radiation therapy regimen (n = 30): non-irradiated; 50 Gy; and 70 Gy. Three 1.0 mm diameter root canal-like cavities were made in each dentin slice. Each cavity was filled with the following sealers: AH Plus Jet (epoxy resin), BioRoot RCS (bioceramic) and Endofill (zinc oxide). After 7 days, a micro push-out test was performed in a Universal Testing Machine. Failures were analyzed using a stereomicroscope. Statistical analysis included the application of Three-Way Analysis of Variance (ANOVA) followed by Bonferroni's post-hoc test (α = 5 %).

Results

Non-irradiated specimens filled with AH Plus Jet and BioRoot RCS had higher bond strength than the irradiated ones, regardless of the radiation therapy regimen (p < 0.001). There were no differences between specimens irradiated with 50 Gy and 70 Gy for AH Plus Jet and BioRoot RCS (p > 0.05). There were no differences among non-irradiated and irradiated specimens for Endofill at the cervical third (p = 0.406). Cohesive failure was the most frequent before irradiation. After irradiation, mixed failure was the most frequent.

Conclusion

Radiation therapy reduced the bond strength of both epoxy resin and bioceramic sealers. The zinc oxide-based sealer exhibited the lowest dislodgement resistance, making it a less suitable option for patients undergoing radiotherapy.