Ion Release from Endodontic and Restorative Dental Materials: Effects of pH and Time

Root canal sealers remain in long-term contact with dental tissues, raising concerns about their potential adverse effects.

This study evaluates the physicochemical properties and ion-release profiles of three dental materials: zinc oxide/eugenol-based sealer, zinc phosphate cement (luting agent), and glass-ionomer cement (restorative material) under acidic (pH 4) and neutral (pH 7) conditions over 24 h and 30 days to determine their behavior and bioactivity in vitro. The materials were evaluated for their setting time, consistency, film thickness, solubility, and ion release using atomic emission spectrometry. The influence of pH and exposure time on ion release was analyzed using multiple regression analysis.

All tested materials met the ISO standards for their respective categories. The zinc oxide/eugenol and zinc phosphate cements released increased levels of zinc in acidic environments (pH 4), suggesting potential antimicrobial properties. The glass-ionomer cement exhibited higher silicon and strontium release under a neutral pH (pH 7), indicating potential remineralization effects. Silver from the zinc oxide/eugenol material was below the detection limit of the applied method, suggesting minimal ion release under the tested conditions. Maximum zinc release from root canal sealer occurred after 30 days at pH 4 (1.39 ± 0.26 mg), while the highest silicon release from glass-ionomer cement was observed at pH 7 after 30 days (1.03 ± 0.21 mg).

Zinc oxide/eugenol materials exhibited increased zinc release under acidic conditions. In contrast, the restorative and luting materials demonstrated distinct ion-release patterns, aligning with their respective intended applications rather than endodontic purposes.