Antonijevic Djordje, Medigovic Ivana, Zrilic Milorad, Jokic Bojan, Vukovic Zorica, Todorovic Ljubomir
Clin Oral Investig. 2014 Jul;18(6):1597-604. doi: 10.1007/s00784-013-1130-0.
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 saline.
Specimens 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 4-mm diameter and 6-mm high specimens and Universal testing machine. High-pressure 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 one-way ANOVA and post hoc Tukey test (P < 0.05).
The 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 cut-off. ZrO2 and YbF3 increased the compressive strength of PC, but it was not statistically significant (P > 0.05), while Bi2O3 decreased it (P < 0.05). All radiopacifiers significantly increased the porosity of the experimental cements (P < 0.05). Bi2O3 extended the setting time of PC (P < 0.05), whilst ZrO2 and YbF3 did not significantly affect it (P > 0.05).
ZrO2 and YbF3 may be used as a suitable alternative to replace Bi2O3 in MTA without influencing its physical properties.
本研究旨在评估白色波特兰水泥（PC）添加氧化铋（Bi2O3）、二氧化锆（ZrO2）和三氟化镱（YbF3）后，在37°C蒸馏水中或磷酸盐缓冲盐水中浸泡7天后的射线不透性、抗压强度、凝固时间和孔隙率。
制备直径8mm、厚度1mm的试样，PC中添加10%、20%和30%重量比的Bi2O3、ZrO2或YbF3。ProRoot MTA（美国登士柏公司，塔尔萨，俄克拉何马州）和纯PC用作对照。对于射线不透性评估，将试样与牙齿切片和铝阶梯楔在ExtraSpeed咬合牙科胶片（柯达公司，纽约州罗切斯特）上进行射线照相。计算每个试样的平均光密度，并将其用于将材料的射线不透性表示为铝的等效厚度。使用直径4mm、高6mm的试样和万能试验机测量抗压强度。采用高压汞侵入孔隙率仪（Carlo Erba Porosimeter 2000）测量试样的孔隙率。使用重量为100g的针测量凝固时间。使用扫描电子显微镜（美国TESCAN Mira3 XMU公司）评估试样的形态。数据采用单因素方差分析和事后Tukey检验进行分析（P<0.05）。
添加至少10%重量比的Bi2O3和20%重量比的ZrO2或YbF3的PC显示出比推荐的3mmAl截止值更高的射线不透性值。ZrO2和YbF3提高了PC的抗压强度，但无统计学意义（P>0.05），而Bi2O3降低了抗压强度（P<0.05）。所有射线阻射剂均显著增加了实验水泥的孔隙率（P<0.05）。Bi2O3延长了PC的凝固时间（P<0.05），而ZrO2和YbF3对其无显著影响（P>0.05）。
ZrO2和YbF3可作为合适的替代品，在不影响其物理性能的情况下替代MTA中的Bi2O3。
