(PR163) Assessment of Bioceramic Sealer Solubility with Acidic, Alkaline, and Chelating Solutions: an In Vitro Study

Objective: The only solvent suggested to facilitate the removal of tricalcium silicate-based sealers during endodontic retreatment is acid, which also demineralizes radicular dentin. This study compared the solubility of EndoSequence BC sealer (BCS) in solutions with different pH values, a commercially available 17% EDTA, and a novel preparation of EDTA buffered to pH 10.

Methods: Solubility tests were performed according to ISO specification 6876:2012. Sealer samples were prepared in 4x6mm cylindrical Delrin molds and after setting, were weighed and randomly divided into 6 groups (n=10). The samples were immersed in 7.5 mL of either: 1) pH 4 acetate buffer; 2) pH 6 acetate buffer; 3) pH 7 deionized water (negative control); 4) pH 10 bicarbonate buffer; 5) 17% EDTA; or 6) pH 10 EDTA for 24 hours at 37° C and then weighed again. Solubility was calculated as a function of weight loss and statistically analyzed using two-way ANOVA with Tukey’s post-hoc tests.

Results: Solubility values (average % ± standard deviation) for each group were: 1) 48.6%±2.8; 2) 41.4%±4.6; 3) 13.5%±1.9; 4) 13.2%±3.2; 5) 32.6%±6.4; and 6) 51.1%±4.7. BCS was significantly more soluble in both pH 4 acetate buffer (group 1) and pH 10 EDTA (group 6) in comparison to the other 4 groups (p < 0.05). There was no statistically significant difference in solubility between the pH 4 acetate buffer and pH 10 EDTA groups (p>0.05).

Conclusion: Both pH 4 acetate buffer and pH 10 EDTA were effective solvents for BCS and may help facilitate tricalcium silicate-based sealer removal during endodontic retreatment procedures.