RESUMO
Background: This research assessed the compressive strength and microhardness of glass-ionomer cement (GIC) after incorporating seashell nanoparticles and evaluated the inert fluoride-releasing ability. Methods: Seashell nanoparticles were synthesized by a mechanical grinding protocol. These particles were characterized by transmission electron microscopy and energy dispersive x-ray and added to the glass-ionomer powder in a weight-to-weight ratio. Seventy-five study samples were distributed into eight samples for each study group (control, 5%, and 10% seashell) to have 24 samples for each test of the study (compressive strength, microhardness, and fluoride release). One sample per group was prepared for the Fourier transform infrared spectroscopy (FTIR) test. The fluoride ion release was measured after one and four weeks of incubation period at 37 ºC, while other tests were conducted after 24 hours of incubation. Results: In all the test variables, the 10% seashell group showed the highest significant mean, followed by the 5% seashell and the control group. However, there was no significant difference between the 5% and 10% seashell groups in the first week of fluoride release. Conclusion: According to the results, 10% seashell nanoparticles were the best to improve the mechanical properties of GIC and boost the fluoride-releasing potential.