The aim of this study was to evaluate volumetric and morphological stability of 3 root-end filling materials in addition to porosity and interface voids, using micro-computed tomography (µCT) in high resolution and a highly accurate approach for image analysis. Following root-end resection and apical preparation, two-rooted maxillary premolars were divided into three groups, according to the filling materials: White MTA Angelus, Biodentine, and IRM. Samples were scanned by µCT at 5 µm after the setting time and at time intervals of 7 and 30 days after immersion in phosphate-buffered saline (PBS). Volumetric and morphological changes besides material porosity and interface voids were evaluated by comparing initial values and those obtained after immersion. Data were analyzed statistically, using ANOVA and t-tests (α = 0.05). All materials showed volumetric stability. Regarding the morphological changes, Biodentine had a significant thickness reduction after storage in PBS when compared with MTA. Biodentine also showed an increase in porosity, as well as in percentage and thickness of voids after 30 days of immersion. In conclusion, µCT in high resolution and an accurate image analysis approach may be used to evaluate morphological changes of endodontic materials. Although Biodentine showed suitable adaptability and lower values of porosity than MTA, after PBS immersion there was a dimensional reduction of this material, besides an increase in porosity and interface voids.

中文翻译：

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显微计算机断层扫描在模拟生理条件下高分辨率评估3种根端填充材料的尺寸和形态变化。

这项研究的目的是使用高分辨率的微型计算机断层扫描（µCT）和高精度的图像分析方法，评估除孔隙度和界面空隙外的3种根端填充材料的体积和形态稳定性。在根端切除和根尖准备之后，根据填充材料将两根上颌前磨牙分为三组：白色MTA Angelus，Biodentine和IRM。在凝固时间之后，在5 µm处以及在浸入磷酸盐缓冲盐水（PBS）后的7和30天的时间间隔内，通过µCT扫描样品。通过比较初始值和浸泡后获得的值，评估了材料孔隙率和界面空隙以外的体积和形态变化。使用ANOVA和t检验对数据进行统计学分析（α= 0.05）。所有材料均显示出体积稳定性。关于形态变化，与MTA相比，Biodentine在PBS中储存后厚度明显减小。浸泡30天后，Biodentine的孔隙率以及空隙的百分比和厚度也会增加。总之，可以使用高分辨率的µCT和精确的图像分析方法来评估牙髓材料的形态变化。尽管Biodentine与MTA相比显示出合适的适应性和较低的孔隙率值，但在PBS浸泡后，该材料的尺寸减小了，除了孔隙率和界面空隙增加了。以及浸入30天后的空隙百分比和厚度。总之，可以使用高分辨率的µCT和精确的图像分析方法来评估牙髓材料的形态变化。尽管Biodentine与MTA相比显示出合适的适应性和较低的孔隙率值，但在PBS浸泡后，该材料的尺寸减小了，除了孔隙率和界面空隙增加了。以及浸入30天后的空隙百分比和厚度。总之，可以使用高分辨率的µCT和精确的图像分析方法来评估牙髓材料的形态变化。尽管Biodentine与MTA相比显示出合适的适应性和较低的孔隙率值，但在PBS浸泡后，该材料的尺寸减小了，除了孔隙率和界面空隙增加了。