The effect of mesoporous silica doped with silver nanoparticles on glass ionomer cements; physiochemical, mechanical and ion release analysis

Abstract

Background: The purpose of the study was to evaluate the effect of adding mesoporous silica with silver nanoparticles to conventional glass ionomer cements (GIC) on its, physical, chemical, mechanical properties and ion release analysis.

Methods: Synthesized mesoporous silica with silver nanoparticles were added in 1, 3 and 5% by weight to the liquid component of GIC forming three experimental groups and compared with plain GIC as control group. Physical and chemical characterization were conducted using nano-computerized tomography (NanoCT) and Fourier transform infrared spectroscopy. Surface microhardness, water sorption and solubility were analyzed. Ion release was investigated using Inductive Coupled Plasma-Optical Emission Spectroscopy and High Performance Liquid Chromatography. Statistical analysis between different groups for the set parameters using parametric and non-parametric tests. The results were analysed using one way analysis of variance (p < 0.05).

Results: Synthesized mesoporous silica with silver nanoparticles were of 7.28 ± 5.0 nm in diameter with a spherical morphology. NanoCT revealed less porosities for 3 wt %. Microhardness showed a statistically significant difference for 5 wt% at day 1 and 21 ( p < 0.0001). Water sorption values decreased significantly on day 14 compared to day 7 for control, 1, 3 and 5 wt%. Control specimens showed highest concentration of fluoride release followed by 5, 3 and 1 wt%.

Conclusion: Mesoporous silica with silver nanoparticles modified glass ionomer cements showed comparable microhardness to conventional GIC. Ion release was evident from the modified specimens. Silver remained within the GIC for atleast four weeks following incorporation.

Keywords: Glass Ionomer cements; Ion release; Mesoporous silica; Silver nanoparticles.

Fig. 1

Experimental flow chart for synthesis and characterization used

Fig. 2

Representing the survey spectra of silica doped silver nanoparticles showing the oxygen, silver, sodium, carbon and silver peaks representing the binding energy. Binding energy graphs of (b) Silica and (c) Silver and their molecular arrangement along with Silver and its different molecular configurations. (d) Transmission electron microscopy images of mesoporous silica nanoparticles doped with silver nanoparticles. Image is scaled at 50 nm. Inset image of the frequency distribution of AgNP

Fig. 3

FTIR-ATR spectral data of (a) Mesoporous silica with silver nanoparticles (b) the liquid component of control and experimental groups ( 1, 3 and 5 wt%) (c) Set GIC cement spectra collected after 24 h., (d) Finger print region from 500 to 1800 cm^-1 of the GIC liquid and set cement

Fig. 4

Nano computerized tomography of (a) control, (b) 1 wt%, (c) 3 wt % and (d) 5 wt %. Images shown are cross-sectional and longitudinal sections. Porosities can be visualized along with their distribution

Fig. 5

Porosity inclusion analysis of control and experimental specimens (a) Materials Volume (mm³). (b) Defect volume ( mm³), (C) Defect volume (%).). Statistically significant is denoted by, * = p < 0.01, ** = p < 0.001, *** = p < 0.0001

Fig. 6

Microhardness (B) Compressive strength of control, 1, 3 and 5 wt% specimens over a period of 21 days. Values shown are mean ± SD ( n = 3). Statistically significant is denoted by, ** = p < 0.001, **** = p < 0.0001

Fig. 7

Ion release analysis conducted by ICP-OES for control, 1, 3 and 5 wt% specimens to quantify the release of (a) Al, (b) Ca, (c) Na, (d) P, (e) Ag ions in parts per million (ppm) and (f) Fluoride release analysed by HPLC in mg/ml over a period of 4 weeks. Values shown are mean ± SD. Statistically significant is denoted by, ** = p < 0.001, **** = p < 0.0001