Characterization physico-mechanical and chemical properties of nano-hydroxyapatite-silica added glass ionomer cement
Loading...
Date
2020-01
Authors
Moheet, Imran Alam
Journal Title
Journal ISSN
Volume Title
Publisher
Pusat Pengajian Sains Pergigian, Universiti Sains Malaysia
Abstract
The aim of this study was to synthesize and characterize different nanohydroxyapatite-
silica (nano-HA-SiO2) particles with various silica concentrations and to
investigate the effects of adding nano-HA-SiO2 to the conventional glass ionomer cement
(Fuji IX GC). Nano-HA-SiO2 was synthesized using one-pot sol-gel technique, which was
then characterized using fourier transform infrared spectroscopy (FTIR), x-ray diffraction
(XRD), scanning electron microscope (SEM) and transmission electron microscope
(TEM). Further investigations were carried out on nano-HA-SiO2 added glass ionomer
cement (nano-HA-SiO2-GIC) to compare their mechanical (surface hardness, compressive
strength, flexural strength, and shear bond strength), chemical (fluoride ion release,
solubility and ion-exchange) and physical properties (colour stability, surface roughness,
sorption and micro-leakage) in relation to conventional glass ionomer cement (cGIC). It
was found that nano-powder consisted of a mixture of spherical silica particles (~50 nm)
and elongated hydroxyapatite particles in the range between 100-200 nm. Hardness,
compressive strength, and flexural strength of nano-HA-35SiO2-GIC was statistically
higher than that of nano-HA–21SiO2–GIC, nano-HA-11SiO2-GIC. The highest value for
Vickers hardness (64.77 6.18), compressive strength (143.42 13.94 MPa) and flexural
strength (17.68 1.81 MPa) were recorded by addition of 10% nano-HA-35SiO2 to GIC,
leading to an increase of ∼36 %, ∼19.7 % and ∼53.34 % in surface hardness, compressive
strength and flexural strength respectively as compared to conventional glass ionomer
cement (cGIC). 10% nano-HA–35SiO2-GIC also demonstrated higher shear bond strength
(∼17.54 % increase) as compared to cGIC. Nano-HA-35SiO2-GIC was more colour stable
material as it showed “slight - noticeable” change in colour as compared to cGIC that
displayed “noticeable to appreciable” change after 28 days of immersion in distilled water.
Nano-HA-35SiO2-GIC showed significantly lower surface roughness (0.13 ± 0.01 μm) as
compared to cGIC (0.16 ± 0.03 μm) on day 1. Additionally, nano-HA-35SiO2-GIC
showed highly significant difference (p=0.002) in amount of mean F+ release for all the
time intervals as compared to cGIC (p ≤ 0.05). In addition, Nano-HA-35SiO2-GIC
recorded higher values for both solubility and sorption (83.7 ± 19.04 μgmm-3 and 50.92 ±
12 μgmm-3) as compared to cGIC (56.65 ± 10.15 μgmm-3 and 42.64 ± 6.74 μgmm-3). It
also exhibited lower micro-leakage both at occlusal and gingival margins (0.2 ± 0.42 and
2.7 ± 0.67) as compared to cGIC (0.5 ± 0.71 and 3 ± 0.00). A greater ion-exchange was
displayed by nano-HA-35SiO2-GIC at ion-exchange layer (IEL) as well as the tooth
structure (enamel and dentin) as compared to cGIC. The addition of nano-HA-silica to
conventional GIC significantly enhanced the mechanical, physical and chemical
properties except sol-sorption properties of the material. Based on the findings of the
current study, nano-HA-SiO2-GIC can be suggested as a potential dental restorative
material.
Description
Keywords
Glass ionomer cements