Physicochemical Characterization of a Strontium Silicate-Based Root Canal Sealer Compared with Two Conventional Sealers

Objectives: To evaluate the physicochemical properties of a novel strontium silicate-based root canal sealer (C-Root SP) in comparison with a calcium silicate-based sealer (TotalFill BC) and an epoxy resin-based sealer (AH Plus). Methods: Setting time, net mass change (apparent solubility behavior), pH changes, and surface characteristics were assessed based on ISO 6876 and ANSI/ADA Specification No. 57, with minor methodological modifications. Net mass change and pH were evaluated over 28 days. Surface morphology and elemental composition were analyzed after dry and aqueous aging in deionized water using scanning electron microscopy coupled with energy-dispersive X-ray spectroscopy. Data were analyzed using one-way and repeated-measures ANOVA with Tukey’s post hoc test (α = 0.05). Results: AH Plus exhibited the longest initial and final setting times (10.93 ± 0.65 h and 37.33 ± 0.13 h), whereas TotalFill BC showed the shortest (7.98 ± 0.32 h and 30.18 ± 0.20 h); C-Root SP demonstrated intermediate values (9.35 ± 0.38 h and 32.75 ± 0.57 h) (p < 0.001). C-Root SP exhibited positive net mass change values (indicative of net mass loss), ranging from 5.32 ± 4.72% at 24 h to 6.83 ± 5.55% at 28 days, significantly higher than AH Plus and TotalFill BC (p < 0.001), which showed negative values indicative of apparent mass gain. All sealers demonstrated alkaline conditions, with C-Root SP maintaining the highest apparent pH values throughout the evaluation period (p < 0.001). Surface and compositional changes were observed in the bioceramic sealers following aqueous aging, with increased detectable strontium content in C-Root SP. Conclusions: C-Root SP exhibited physicochemical behavior consistent with a strontium-modified calcium silicate-based sealer, characterized by hydration-driven hydroxyl ion release resulting in apparent alkalinity and ion exchange-associated behavior, and dynamic surface changes consistent with those reported for bioceramic materials. Clinical Significance: Strontium incorporation may influence hydration-mediated physicochemical behavior; however, further in vitro and in vivo studies are required to determine its clinical relevance.