Basturk Fatima B, Nekoofar Mohammad Hossein, Gunday Mahir, Dummer Paul M
Department of Endodontics, Faculty of Dentistry, Marmara University, Istanbul, Turkey; Endodontology Research Group, School of Dentistry, College of Biomedical and Life Sciences, Cardiff University, Cardiff, United Kingdom.
Endodontology Research Group, School of Dentistry, College of Biomedical and Life Sciences, Cardiff University, Cardiff, United Kingdom; Department of Endodontics, School of Dentistry, Tehran University of Medical Sciences, Tehran, Iran.
J Endod. 2014 Mar;40(3):441-5. doi: 10.1016/j.joen.2013.08.010. Epub 2013 Oct 13.
The aim of this study was to evaluate the effect of mechanical and manual mixing as well as the effect of ultrasonic agitation during placement on the flexural strength and porosity of mineral trioxide aggregate (MTA).
White ProRoot MTA and white MTA Angelus were used. One gram of each powder was mixed with a 0.34-g aliquot of distilled water. Specimens were mixed either by mechanical mixing of capsules for 30 seconds at 4500 rpm or by a saturation technique and application of a condensation pressure of 3.22 MPa for 1 minute. The mixed slurries of all materials were loaded into 2 × 2 × 25 mm molds for testing flexural strength and 3 × 4 mm molds for evaluation of porosity. Half of the specimens were placed in the stainless steel molds by using indirect ultrasonic activation. All specimens were incubated for 4 days. Micro-computed tomography was used to determine the porosity of each specimen, and a 3-point bending test was used to evaluate flexural strength. Tukey honestly significant difference and independent t tests were carried out to compare the means at a significance level of P < .05.
Irrespective of mixing and placement techniques applied, the flexural strength values of ProRoot MTA were significantly greater than those of MTA Angelus (P < .05). A medium negative correlation was found between flexural strength values and total porosity percentage.
Although mechanical mixing of encapsulated cements was quicker and provided more consistent mixes, this technique along with ultrasonic agitation was not associated with a significant advantage in terms of flexural strength and total porosity over manual mixing.
本研究的目的是评估机械搅拌和手工搅拌以及在放置过程中超声搅拌对三氧化矿物凝聚体（MTA）的抗弯强度和孔隙率的影响。
使用白色ProRoot MTA和白色MTA Angelus。将1克每种粉末与0.34克蒸馏水等分试样混合。通过将胶囊在4500转/分钟下机械搅拌30秒或通过饱和技术并施加3.22兆帕的挤压力1分钟来混合试样。将所有材料的混合浆料装入2×2×25毫米的模具中以测试抗弯强度，并装入3×4毫米的模具中以评估孔隙率。一半的试样通过间接超声激活放置在不锈钢模具中。所有试样孵育4天。使用微计算机断层扫描确定每个试样的孔隙率，并使用三点弯曲试验评估抗弯强度。进行Tukey真实显著差异检验和独立t检验，以在显著性水平P <.05下比较均值。
无论采用何种混合和放置技术，ProRoot MTA的抗弯强度值均显著高于MTA Angelus（P <.05）。发现抗弯强度值与总孔隙率百分比之间存在中等程度的负相关。
尽管封装水泥的机械搅拌更快且提供更一致的混合物，但与手工搅拌相比，该技术以及超声搅拌在抗弯强度和总孔隙率方面没有显著优势。
