Sajjad, Arbaz
(2020)
Evaluation of physico-mechanical, chemical properties and cytotoxicity of fabricated glass ionomer nano zirconia-silica- hydroxyapatite hybrid material.
PhD thesis, Universiti Sains Malaysia.
Abstract
The aim of this study was to synthesize and characterize a nano zirconia-silicahydroxyapatite
(nanoZrO2-SiO2-HA) composite and to investigate the effects of
adding nanoZrO2-SiO2-HA to a conventional glass ionomer cement (cGIC).
NanoZrO2-SiO2-HA composite was synthesized using a one-pot sol-gel technique,
which was then characterized using scanning electron microscope (SEM),
transmission electron microscope (TEM), fourier transform infrared spectroscopy
(FTIR) and x-ray diffraction (XRD). Following the characterization studies, further
investigations were carried out after addition of nanoZrO2-SiO2-HA to cGIC (GIC
nanoZrO2-SiO2-HA) at varying weight percentage (~3% to 9%) to compare their
mechanical properties (compressive strength, flexural strength, and fracture
toughness), physical properties (surface roughness, colour stability and sorptionsolubility),
chemical property (fluoride ion release) and cytotoxicity in relation to
cGIC (Fuji IX). SEM and TEM images were successful in demonstrating that the
particle morphology in terms of size to shape distribution was small and narrow with
low agglomeration. The nano powder consisted of rod-shaped HA crystallites (~114
nm) interspersed with spherical silica (~18 nm) and zirconia (~39 nm) particles. The
FTIR spectra indicated some molecular interaction presented between the nanoZrO2-
SiO2-HA and GIC. The XRD diffractogram indicated the presence of peaks for ZrO2,
SiO2 and HA. Compressive strength, flexural strength and fracture toughness of GIC
5%nanoZrO2-SiO2-HA was statistically higher than that of other percentages of GIC
nanoZrO2-SiO2-HA and cGIC. The highest values recorded were- compressive
strength (144.12 13.88 MPa), flexural strength (18.12 2.33 MPa) and fracture
toughness (1.35 0.15 MPa.m1/2), leading to an increase of ~30 %, ~26 % and ~57 %
respectively, as compared to cGIC. Additionally, GIC 5%nanoZrO2-SiO2-HA had a
roughness profile (0.158μm ± 0.29) similar to cGIC (0.151μm ± 0.29). Overall, the
color change (ΔE) values for GIC 5% nanoZrO2-SiO2-HA group were lower than those
of cGIC over a 28 day period and were between slight to perceptible. The GIC
5%nanoZrO2-SiO2-HA showed highly significant difference in the mean fluoride
release for all the time intervals as compared to cGIC (p ≤ 0.05). In addition, GIC
5%nanoZrO2-SiO2-HA recorded lower sorption values (23.64 ± 2.3 μgmm-3) as
compared to cGIC (36.28 ± 2.6 μgmm-3) and higher solubility (66.46 ± 2.4 μgmm-3)
as compared to cGIC (56.76 ± 1.6 μgmm-3). The results of cytotoxicity testing showed
that GIC 5%nanoZrO2-SiO2-HA demonstrated cytotoxicity at 24 h incubation for 200
mg/ml conc. However, at 72 h incubation it exhibited lower cytotoxic response as
compared to cGIC which was statistically significant (p<0.05) at 200 mg/ml
concentration of the material extract. The addition of nanoZrO2-SiO2-HA to cGIC
significantly enhanced its physico-mechanical, chemical properties and demonstrated
a favourable cytotoxic response. Based on the results of our recently concluded study,
GIC nanoZrO2-SiO2-HA has the potential to be suggested as a restorative dental
material with diverse applications ranging from cavity restoration, core build-up and
as a luting material.
Actions (login required)
 |
View Item |
