Effects of Incorporation of Marine Derived Hydroxyapatite on the Microhardness, Surface Roughness, and Fluoride Release of Two Glass-Ionomer Cements

Background: The aim of this study was to evaluate the effects of incorporation of hydroxyapatite (HA) derived from cuttlefish bone on the microhardness, surface roughness (SR), and fluoride release (FR) of conventional cure, and resin-modified glass-ionomer cement. Methods: There were four groups for each tested material; experimental glass-ionomer were made by addition and of 2, 5, and 10 wt % HA respectively to conventional glass-ionomers Fuji II LC and Fuji IX GP Extra. One group was prepared without the addition of HA particles. For SR and microhardness measurements sectional Teflon molds (5 mm in diameter and 2 mm deep) were used to prepare 10 samples per group (n = 80). The samples were stored in distilled water at 37 °C for 7 days prior to testing. The SR was measured using a contact type profilometer and the microhardness was determined using a Vickers micro-hardness tester at a load of 980 g for 15 s. For FR measurements, there were six samples per group (n = 48), prepared in Teflon molds (8 mm in diameter and 2 mm deep). The FR was measured with an ionoselective electrode in triplicates after 24 h, 7 days, and 45 days. Statistical analysis was performed using one-way ANOVA with Tukey post-hoc test. Results and Conclusion: Microhardness values obtained for Fuji II modified with 10 wt % HA were significantly higher compared to the other two groups tested. Comparison of materials with respect to SR showed significant difference between them (p < 0.0001) with Fuji II and Fuji IX modified with HA having higher SR values. Regarding FR, Fuji IX showed statistically significant higher results than Fuji II, independently of HA modification, and groups modified with 2 and 5 wt % HA showed significantly increased fluoride release in all three time points.