Compressive strength and fluoride release profile of a glass ionomer cement reinforced with silver-hydroxyapatite-silica hybrid nanoparticles: An in vitro study

Objectives: This study aimed to prepare a glass ionomer (GI) cement reinforced with silver-hydroxyapatite-silica (Ag/HA/Si) hybrid nanoparticles and assess its compressive strength and fluoride release profile.

Material and methods: In this in vitro, experimental study, 60 cylindrical specimens were fabricated with 4 mm diameter and 6 mm height in 6 groups (n = 10) using BracePaste composite, GC Fuji II LC pure RMGI, and RMGI reinforced with 0.1wt%, 0.5wt%, 1wt%, and 2wt% Ag/HA/Si hybrid nanoparticles. The specimens were subjected to compressive force in a universal testing machine to measure their compressive strength (MPa). To assess their fluoride release profile, discs with 3 mm diameter and 2 mm thickness were fabricated from Fuji II LC pure resin-modified glass ionomer (RMGI), and RMGI with 0.1wt%, 0.5wt%, 1wt%, and 2wt% hybrid nanoparticles, and the concentration of released fluoride was measured by a digital ion-selective electrode. Data were analysed by ANOVA and Scheffe test (alpha = 0.05).

Results: The compressive strength was 114.14 MPa for BracePaste composite, and 97.14, 97.84, 100.65, 109.5, and 89.33 MPa for GI groups with 0%, 0.1%, 0.5%, 1% and 2% hybrid nanoparticles, respectively, with no significant difference among them (P = 0.665). Addition of 1% (0.21 ± 0.07 μg/mL, P = 0.029) and 2% (0.45 ± 0.22 μg/mL, P = 0.000) hybrid nanoparticles to RMGI significantly increased the amount of released fluoride, compared with the control group (0.09 ± 0.03 μg/mL).

Conclusions: Addition of Ag/HA/Si hybrid nanoparticles to RMGI in the tested concentrations had no significant effect on its compressive strength but addition of 1wt% and 2wt% concentrations of Ag/HA/Si hybrid nanoparticles increased its fluoride release potential.