Al-Ibrahim, Hasan Subhi Azeez
(2021)
Physico-chemical properties and effects of chitosan-based accelerated portland cement on stem cells from human exfoliated deciduous teeth.
PhD thesis, Universiti Sains Malaysia.
Abstract
Advancement in the field of endodontic such as techniques, instrumentations
and materials have considerably improved the oral health care and have made the
dental treatment more efficient, as well as cost and time effective. Accelerated Portland
cement (APC) is a potential material with favourable chemical, physical and biological
properties. It was studied as an alternative material to overcome the major limitations
of mineral trioxide aggregate (MTA) and portland cement (PC) such as delayed setting
time and high cost of MTA. Chitosan (CT) has also been used in numerous medical
applications due to its various biological properties. In this study, APC was prepared
in combination with CT and designated as APC-CT. This study aimed to evaluate the
chemical, physical and mechanical properties of APC-CT and to evaluate its
biocompatibility, mineralization activity and dentinogenic/osteogenic differentiation
potential on stem cells from human exfoliated deciduous teeth (SHED). APC-CT was
prepared with various CT concentrations of 0.625%-, 1.25%- and 2.5%-CT solutions,
and APC was used as control. The chemical characterizations by FTIR and
FESEM/EDX were evaluated, in addition to the physical and mechanical properties
such as setting time, compressive strength, surface microhardness, pH and solubility.
Then, the effect of APC-CT on cell viability, attachment and apoptosis were assessed.
The mineralization activity of SHED was evaluated by Alizarin Red staining and Von
Kossa stain. Finally, the dentinogenic/osteogenic differentiation of SHED was
analysed by evaluating the gene expression of selected dentinogenic/osteogenic
markers i.e. DSPP, MEPE, DMP-1, OPN, OCN, OPG, RANKL, RUNX2, ALP and
COL1A1 by real-time PCR. The results confirmed the interaction of CT with APC by
FTIR spectra. The surface morphology of APC-CT was characterized by the presence
of CT crystallites which spread and filled the spaces in APC structure that resulted in
more homogeneous phases. The chemical compositions of APC and APC-CT were
almost identical with intensified O, C and Si in APC-CT. The setting time,
compressive strength, microhardness, pH and solubility obtained ranged between
46.6-48.5 min, 51.3-39.1 MPa, 44.89-38.57 HV, 11.04-11.02 (24 hrs) and 3.23-2.44%,
respectively. CT improved the pH and solubility of APC and extended its setting times.
However, compressive strengths were reduced and minimum effect on microhardness
was observed. Cytotoxicity assays demonstrated that APC-CT supported the cell
proliferation and interaction of SHED to the materials; as well as no apoptotic effect
was observed. Alizarin Red and Von Kossa stainings demonstrated increased
mineralization activity of SHED when treated with APC-CT. The expressions of
DSPP, MEPE, DMP-1, OPN, OCN, OPG and RANKL markers were up-regulated in
APC-CT-treated SHED. While, the expressions of RUNX2, ALP and COL1A1 markers
were down-regulated. These findings demonstrate that APC-CT exhibits good
chemical, physical and mechanical properties. APC-CT is non-toxic and promotes
dentinogenic/osteogenic differentiation and mineralization activity; which provides
potential applications of APC-CT in tooth/bone tissue engineering.
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