Comparison of Fillers Formulated in a Nanofluorapatite Composite

Objectives: To compare fillers formulated within a composite system that also includes nanoparticles that are ideal for modern biomimetic dentistry.
Methods: Experimental composites were formulated with 20% resin to 80% powder ratio and a filler mix including either a ZrO₂-SiO₂ prepolymerized filler (Sukygung AT Ltd., Ansan-city, Gyeonggi-do, Korea) or aluminum strengthened ZrO₂-SiO₂ sintered nanoparticles (Sukgyung AT Ltd., Ansan-city, Gyeonggi-do, Korea) along with nanoparticles for biomimetric dentistry from Nanodentica (Gothenburg, Sweden). The ISO 4049 flexural strength, compressive strength, diametral tensile strength, ISO 4049 depth of cure, and degree of conversion of the formulations were tested and compared. The null hypothesis is the fillers will perform the same and any observed differences are due to random error.
Results: When analyzed using the t-test, the composite with the sintered nanoparticles had significantly higher values in flexural strength, and diametral tensile strength and thus the null hypothesis is rejected for these tests. The composite with the prepolymerized filler had significantly higher values in compressive strength and depth of cure and thus the null hypothesis is rejected for these tests. The degree of conversion difference between them was not statistically significant and the null hypothesis is accepted for this test.
Conclusions: The sintered nanoparticles resulted in higher flexural strength, and diametral tensile strength. The prepolymerized filler resulted in higher compressive strength and depth of cure compared to the sintered nanoparticle formulation. These latter results could be due to the differences in translucency of the composite formulations as they have statistically similar degrees of conversion.