Comparative Analysis of Calcium Dynamics in Regular-Set versus Fast-Set Bioceramics: Impact on Cytotoxicity and Apatite Formation

Introduction: The objective of this study was to assess the calcium ions (Ca²⁺) release, pH shift, bioactivity, and cytotoxicity of both forms of EndoSequence Root Repair Material: regular set (ES) and fast set (ESF).

Methods: ES (n = 10) and ESF (n = 10) forms were tested for their bioactivity. Elemental analysis was done on the fresh material and material immersed in phosphate-buffered saline (PBS) for 30 days. The surface crystal formation was studied. Cytotoxicity was evaluated at different material concentrations using a human hepatocellular cancer cell line (Huh-7).

Results: Both materials contain Ca, P, Ta, Zr, and Si as major elements. Both ES and ESF have a limited percentage of ytterbium and neodymium. In the fresh material, compared with the ESF, the ES had a higher Ca²⁺ concentration with a homogeneous surface distribution. However, the ESF released significantly more Ca²⁺ (P < .05) and had a higher pH over the 7-day course. When the material was immersed in PBS, the ESF exhibited a significantly higher Ca/P ratio of 2.95, while ES had 2.16 Ca/P ratio (P < .05). The ESF had a greater capacity to precipitate and grow hydroxyapatite (HA) than ES, resulting in more mature crystals forming on the surface. Both SE and ESF demonstrated low cytotoxicity against Huh-7 cells.

Conclusions: When ES and ESF were submerged in simulated bodily fluid, both forms produced apatite crystals at the dentin material interface, releasing high Ca²⁺ and displaying a prolonged high pH with high bioactivity potential. Both forms had comparable low cytotoxicity. A higher Ca²⁺ release in ESF indicates dynamic bioactivity, which should be aligned with the clinical requirements.