Niobium Calcium Phosphate in Experimental Resin Endodontic Sealer Properties

Objectives: To synthesize calcium phosphate particles with niobium, incorporate them into an experimental resin-based endodontic sealer, and evaluate their properties.
Methods: Calcium phosphate particles with niobium were synthesized by mixing NaCl, KCl, Na₂HPO₄, KH₂PO₄, CaCl₂, and NbCl₅, by precipitation synthesis method. A dual-cure experimental endodontic sealer was formulated using UDMA, BISEMA, and GDMA, with camphorquinone, DHEPT, and benzoyl peroxide as activator/initiator. The particles were added to the sealer at three concentrations: 10 wt.%, 20 wt.%, and 30 wt.%. A control group without particles was used for comparison. The evaluated properties included radiopacity, degree of conversion, flexural strength, flow, and film thickness. Data were analyzed by one-way ANOVA and Tukey.
Results: Groups with particle addition showed higher radiopacity and lower degree of conversion compared to the control group (p<0.05). The control group exhibited the highest flexural strength, while groups with particle addition showed a significant reduction (p<0.05). Regarding flow, groups with particle addition had lower flow values, with no statistical difference between the 20 wt.% and 30 wt.% addition groups. Film thickness was higher in groups with particle addition (p<0.05).
Conclusions: It was possible to successfully synthesize calcium phosphate particles with niobium. The addition of particles at concentrations of 10%, 20%, and 30%, by weight, reduced flexural strength, degree of conversion, and flow, while increasing film thickness and radiopacity of experimental sealers.