Radiopacifier Particle Size Impacts the Physical Properties of Tricalcium Silicate-based Cements

Introduction: The aim of this study was to evaluate the impact of radiopaque additive, bismuth oxide, particle size on the physical properties, and radiopacity of tricalcium silicate based cements. Methods: Six types of tricalcium silicate cement (CSC) including CSC without bismuth oxide, CSC + 10% (wt%) regular bismuth,oxide (particle size 10,mu m), CSC + 20% regular bismuth oxide (simulating white mineral trioxide aggregate [WMTA]) as a control, CSC + 10% nano bismuth oxide (particle size 50-80 nm), CSC + 20% nano-size bismuth oxide, and nano WMTA (a nano modification of WMTA comprising nanoparticles in the range of 40-100 nm) were prepared. Twenty-four samples from each group were divided into 4 groups and subjected to push-out, surface inicrohardness, radiopacity, and compressive strength tests. Data were analyzed by 1-way analysis of variance with the post hoc Tukey test. Results: The push-out and compressive strength of CSC without bismuth oxide and CSC with 10% and 20% nano bismuth oxide were significantly higher than CSC with 10% or 20% regular bismuth oxide (P < .05). The surface micro-hardness of CSC without bismuth oxide and CSC with 10% regular bismuth oxide had the lowest values (P < .05). The lowest radiopacity values were seen in CSC without bismuth oxide and CSC with 10% nano bismuth oxide (P < .05). Nano WMTA samples showed the highest values for all tested properties (P < .05) except for radiopacity. Conclusions: The addition of 20% nano bismuth oxide enhanced the physical properties of CSC without any significant changes in radiopacity. Regular particle-size bismuth oxide reduced the physical properties of CSC material for tested parameters.