Department of Endodontics, Faculty of Dentistry, Marmara University, Istanbul, Turkey.
School of Dentistry, College of Biomedical and Life Sciences, Cardiff University, Cardiff, UK.
Clin Oral Investig. 2018 May;22(4):1675-1680. doi: 10.1007/s00784-017-2241-9. Epub 2017 Dec 29.
The aim of this study was to evaluate the effect of various mixing techniques as well as the effect of ultrasonic placement on hydration of mineral trioxide aggregate (MTA) using X-ray diffraction (XRD) analysis.
One gram of ProRoot MTA and MTA Angelus powder was mixed with a 0.34-g of distilled water. Specimens were mixed either by mechanical mixing of capsules for 30 s at 4500 rpm or by manual mixing followed by application of a compaction pressure of 3.22 MPa for 1 min. The mixtures were transferred into the XRD sample holder with minimum pressure. Indirect ultrasonic activation was applied to half of the specimens. All specimens were incubated at 37 °C and 100% humidity for 4 days. Samples were analyzed by XRD. Phase identification was accomplished by use of search-match software utilizing International Centre for Diffraction Data (ICDD).
All specimens comprised tricalcium silicate, calcium carbonate, and bismuth oxide. A calcium hydroxide phase was formed in all ProRoot specimens whereas among MTA Angelus groups, it was found only in the sample mixed mechanically and placed by ultrasonication.
Mechanical mixing followed by ultrasonication did not confer a significant disadvantage in terms of hydration characteristics of MTA.
Clinicians vary in the way they mix and place MTA. These variations might affect their physical characteristics and clinical performance. For ProRoot MTA, the mixing and placement methods did not affect its rheological properties, whereas for MTA Angelus, mechanical mixing combined with ultrasonic placement enhanced the calcium hydroxide phase formation.
本研究旨在通过 X 射线衍射（XRD）分析评估不同混合技术以及超声放置对矿物三氧化物聚合体（MTA）水化的影响。
将 1 克 ProRoot MTA 和 MTA Angelus 粉末与 0.34 克蒸馏水混合。通过以 4500rpm 的速度机械混合胶囊 30 秒或手动混合后施加 3.22MPa 的压实压力 1 分钟来混合样品。将混合物以最小压力转移到 XRD 样品架中。将一半的样品进行间接超声激活。所有样品在 37°C 和 100%湿度下孵育 4 天。通过 XRD 进行样品分析。使用国际衍射数据中心（ICDD）的搜索匹配软件完成相鉴定。
所有样品均由硅酸三钙、碳酸钙和氧化铋组成。所有 ProRoot 样品中均形成了氢氧化钙相，而在 MTA Angelus 组中，仅在机械混合和超声放置的样品中发现。
机械混合后再进行超声处理在 MTA 的水化特性方面没有明显的劣势。
临床医生在混合和放置 MTA 的方式上存在差异。这些差异可能会影响其物理特性和临床性能。对于 ProRoot MTA，混合和放置方法不会影响其流变性，而对于 MTA Angelus，机械混合结合超声放置会增强氢氧化钙相的形成。
