Effect of calcium silicate and radiopacifier proportions on the physicochemical properties of endodontic calcium silicate-based sealers

OBJECTIVES: This study investigated how varying calcium silicate (30-50%) and radiopacifier (45-65%) proportions affect the physicochemical properties in formulations P1–P3, compared to Bio-C Sealer, AH Plus Bioceramic and AH Plus Jet. MATERIAL AND METHODS: Flowability, solubility, and radiopacity were investigated according to ISO 6876/2012 standards. Setting times were measured based on ASTM C 266-2008 standards. Volumetric changes and pH were assessed using acrylic teeth (n=10) instrumented to #40.04 and filled with the sealers. pH was measured at 3, 24, 72, and 168 hours. The specimens were scanned using micro-CT immediately after filling and after 7 days. pH was measured at 3, 24, 72, and 168 hours. RESULTS: The P1 showed comparable initial setting time to AH Plus Bioceramic (p>0.05). All calcium silicate-based sealers demonstrated higher solubility than AH Plus Jet (p<0.05), with P3 being the only calcium silicate formulation that met ISO solubility standards. P1 and AH Plus Jet had superior radiopacity (p < 0.05). Bio-C Sealer and AH Plus Bioceramic showed higher volume alteration than P2 (p<0.05). P1, P2, and P3 demonstrated stable volumetric changes and progressive alkalinization (pH peak at 72h). Bio-C Sealer significantly increased the pH over time, except between 24 and 168 hours (p>0.05). CONCLUSIONS: Variations in the proportions of tricalcium silicate and radiopacifiers significantly influenced the sealers' properties. P1 (30% calcium silicate/65% radiopacifier) demonstrated superior radiopacity and flowability, while P3 (50% calcium silicate/45% radiopacifier) was the only calcium silicate-based sealer complying with ISO solubility standards. CLINICAL RELEVANCE: Variations in the proportions of calcium silicate and radiopacifiers significantly influenced the sealers' properties. The calcium silicate-based endodontic sealer with 50% calcium silicate and 45% radiopacifier demonstrated ISO-compliant solubility while maintaining optimal physicochemical balance.