Authors: Djordje Antonijevic Ivana Medigovic Milorad Zrilic Bojan Jokic Zorica Vukovic Ljubomir Todorovic
Publish Date: 2013/11/15
Volume: 18, Issue: 6, Pages: 1597-1604
Abstract
The aims of this study were to evaluate the radiopacity compressive strength setting time and porosity of white Portland cement PC with the addition of bismuth oxide Bi2O3 zirconium dioxide ZrO2 and ytterbium trifluoride YbF3 after immersion at 37 °C for 7 days in distilled water or phosphate buffer salineSpecimens measuring 8 mm in diameter and 1 mm in thickness were fabricated from PC with the addition of 10 20 and 30 wt Bi2O3 ZrO2 or YbF3 ProRoot MTA Dentsply Tulsa OK USA and pure PC were used as controls For radiopacity assessments specimens were radiographed alongside a tooth slices and an aluminum stepwedge on Extraspeed occlusal dental films Insight Kodak Rochester New York Mean optical density of each specimen was calculated and used to express radiopacity of the material as an equivalent thickness of aluminum Compressive strength was measured by using 4mm diameter and 6mm high specimens and Universal testing machine Highpressure mercury intrusion porosimeter Carlo Erba Porosimeter 2000 was employed to measure the porosity of the specimens The setting time was measured by using a needle of 100 g in weight The morphology of specimens was evaluated using a scanning electron microscope TESCAN Mira3 XMU USA Inc Data were analyzed by oneway ANOVA and post hoc Tukey test P 005The PC with the addition of at least 10 wt Bi2O3 and 20 wt ZrO2 or YbF3 demonstrated greater radiopacity value than the recommended 3 mmAl cutoff ZrO2 and YbF3 increased the compressive strength of PC but it was not statistically significant P 005 while Bi2O3 decreased it P 005 All radiopacifiers significantly increased the porosity of the experimental cements P 005 Bi2O3 extended the setting time of PC P 005 whilst ZrO2 and YbF3 did not significantly affect it P 005
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