Desenvolvimento e avaliação de cimentos reparadores experimentais à base de silicatos

Abstract

Complex endodontic procedures such as direct pulp capping, perforation sealing, revascularization, and apexification require the use of biomaterials with suitable physicochemical and biological properties. Mineral Trioxide Aggregate (MTA) and Biodentine have been widely used for this purpose due to their bioactivity and ability to induce mineralization, but they present limitations such as high solubility, risk of discoloration, and high cost. In this context, the present study aimed to prepare experimental calcium silicate–based repair cements (ERCs) incorporating zirconium (calcium zirconium silicate – Ca₃ZrSi₂O₉; CZS) or replacing it with strontium (strontium phosphate silicate – Sr₅(PO₄)₂SiO₄; SPS), in combination with auxiliary substances, in order to evaluate their physicochemical properties. The silicates were synthesized by solid-state reaction and used in the formulation of ERCs that were compared with the commercial cements MTA-Angelus (white and gray) and Biodentine. The following parameters were evaluated: setting time (initial and final) and radiopacity (ISO 6876/2012 and ASTM C266), volumetric solubility (micro-CT), pH (pH meter), and calcium/strontium ion release (atomic absorption and inductively coupled plasma optical emission spectrometry). The results showed that the experimental formulations presented initial setting times of 11 min (SPS) and 6 min (CZS), with significant differences between them (p < 0.05). Regarding final setting time, SPS (49 min) presented a significantly higher value compared with all other groups (p < 0.05). Radiopacity remained above the minimum requirement (> 3.0 mm Al), with emphasis on CZS (4.58 mm Al). Solubility was controlled, although CZS exhibited the highest value (3.09%). The pH remained alkaline, with peaks of 10.04 (SPS) and 9.70 (CZS) at 24 h, followed by a decline to 8.31 (SPS) and 7.80 (CZS) at 168 h. In the ion release analysis, a sustained pattern was observed for both cements; CZS showed intermediate release (peak of 25.96 mg/L at 3 h), whereas SPS exhibited lower values (peak of 10.95 mg/L at 168 h), with no significant difference compared with white MTA-Angelus (p < 0.05). Within the limitations of the present study, it can be concluded that the developed cements exhibited physicochemical properties that suggest promising potential for future clinical applications.