Analysis of the long-term solubility and phases of five different root canal sealers in phosphate buffered saline: an in vitro study

Background. The long-term success of root canal therapy depends substantially on the physicochemical stability of endodontic sealers, particularly their solubility and the development of stable crystalline phases during setting. Tricalcium silicate-based sealers (TSBSs) have shown promising biological properties, yet their reported solubility profiles remain inconsistent, raising concerns regarding degradation, gap formation, and the potential for periapical irritation. This study evaluated and compared the solubility and crystalline phase evolution of five commercially available root canal sealers immersed in phosphate-buffered saline (PBS) over extended time intervals. Methods. Twenty-five disc-shaped specimens (n = 5 per material) were prepared using AH Plus Bioceramic (AHPBC), AH Plus (AHP), Ceraseal (CS), BioRoot RCS (BRCS), and MTA Fillapex (MTAF). Solubility was assessed gravimetrically after immersion in PBS for 24 h, 28 days, and 6 months. Phase analysis was performed at each interval using X-ray diffraction (XRD) to identify changes in crystallinity. Results. The solubility values varied markedly among the materials and increased over time for most groups. AHP consistently demonstrated the lowest solubility across all intervals, whereas MTAF and BRCS presented the highest values. XRD analysis revealed distinct crystalline phase patterns for each sealer. AHPBC and CS maintained relatively stable crystalline structures throughout the study period. In contrast, BRCS and MTAF exhibited noticeable fluctuations, and AHP showed high crystallinity initially and after 6 months, indicating greater structural stability. Conclusion. AHP displayed the most favourable physicochemical stability, with minimal solubility and sustained crystallinity. AHPBC and CS also demonstrated stable long-term behaviour, whereas BRCS and MTAF showed greater solubility and structural changes. These findings suggest limitations in the long-term durability of these materials. These findings underscore the importance of sealer selection, particularly when considering long-term stability and the potential impact of material dissolution within the root canal system.