Effect of tungsten as a radiopacifier in enhancing the physical and chemical properties of mineral trioxide aggregate
Date
2012
DOI
Authors
Agolli, Adela
Version
OA Version
Citation
Abstract
Tungsten is a naturally occurring element found in the earth's surface rocks. It is noted for its physical properties such as it has a high density and it has the highest melting point of all the non-alloyed materials. The purpose of this study was to see if the substitution of tungsten for bismuth oxide as a radiopacifier in Mineral Trioxide Aggregate (MTA) will have an impact on its overall solubility, ion dissolution, flexural strength and pH when compared to conventional MTA. Methods: 24 samples were fabricated. They consisted of 12 samples of conventional MTA and 12 samples of tungsten-modified MTA. Half of the samples from the control and experimental group (6 from MTA and 6 from tungsten-modified MTA) were subjected to testing for a 30 day period. The same sets of experiments were followed for the rest of the 12 samples for a 60 day period. Chemical analysis was performed by using a scanning electron microscopy and EDAX. pH, solubility, and biaxial flexural strength were tested in all samples. Inductively Coupled Plasma analysis (ICP) detected the ion dissolution for silicon, calcium, bismuth and tungsten. Results revealed that there were significant changes in pH (p<0.05) in both MTA and tungsten-modified MTA. MTA was able to maintain a higher pH than tungsten-modified MTA for both 30 and 60 day period. Tungsten-modified MTA resulted in same flexural strength values for both 30 and 60 day as compared to MTA. (P<0.05). Solubility was statistically different for both MTA and tungsten-modified MTA at 30 and 60 day period. MTA showed significantly less solubility values in comparison to tungsten-modified MTA. ICP analysis revealed that both groups released calcium, silicon, bismuth and tungsten into the culture medium. Tungsten-modified MTA released more of the ions than conventional MTA. Under the conditions of these experiments, it was concluded that adding tungsten in Portland cement sealers as a radiopacifier will influence some of the chemical and physical properties of MTA, including pH, ion dissolution and solubility. Flexural strength remained unchanged. Further research is needed to evaluate the behavior of tungsten as a radiopacifying agent associated with Portland cement regarding other physicochemical and biological properties of this material.
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Thesis (MSD) --Boston University, Henry M. Goldman School of Dental Medicine, 2012 (Department of Endodontics).
Includes bibliographic references: leaves 83-88.
Thesis (MSD) --Boston University, Henry M. Goldman School of Dental Medicine, 2012 (Department of Endodontics).
Includes bibliographic references: leaves 83-88.
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This work is protected by copyright. Downloading is restricted to the BU community. If you are the author of this work and would like to make it publicly available, please contact open-help@bu.edu.