Evaluation of bioactivity and the ability to release fluoride in glass-ionomer cement/silk fiber composite

Glass-ionomer cements (GICs) are one of the most important dental restorative biomaterials. The aim of this study was to synthesize glass-ionomer‒silk fiber composite and evaluate the effect of adding natural degummed silk fiber on the bioactivity and the ability to release fluoride by glass-ionomer cement. In this study, commercial Fuji II glass-ionomer cement was reinforced by silk fiber. To this end, silk fibers were degummed and glass-ionomer‒silk fiber composite, containing 3 wt% of silk fiber, was fabricated. The morphology, fiber diameter and the presence of fibroin in the silk fiber were investigated by scanning electron microscopy (SEM) and Fourier Transform Infrared Spectroscopy (FTIR), respectively. Artificial saliva was used to evaluate fluoride ion release in a period of 14 days and simulated body fluid (SBF) was used to evaluate the material’s bioactivity for 1, 3, 7, 14 and 21 days. Statistical analysis was carried out with ANOVA using three samples (n=3). Statistical significance was set at p value < 0.05. The results of SEM and FTIR analysis confirmed the presence of fibroin. Fluoride ion release experiment indicated less fluoride ion release from the composite compared to Fuji II GC. Scanning electron microscopy and Fourier transform infrared spectroscopy confirmed the presence of calcium and phosphate, increasing the probability of bioactivity of the composite. Statistical analysis showed that the differences between the results of all the groups were significant (p value < 0.05). Given the limitations of the present study, the results showed that the glass-ionomer cement‒silk fiber composite released less fluoride but at longer periods and is probably more bioactive compared to conventional glass-ionomer.