Micro-CT analysis of filling ability and porosity of root-end filling materials

Abstract Introduction Filling ability of retrograde cavity and porosity are important properties for root-end filling materials and may be evaluated by using microcomputed tomography (micro-CT). Objective To evaluate filling ability and porosity of root-end filling materials using microcomputed tomography (micro-CT). Material and method Cavities with 1 mm internal diameter and 3 mm depth were prepared in bovine dentin sections by using ultrasonic tips (CVD No. 6.1107-6), and filled by Mineral Trioxide Aggregate (MTA); Sealer 26 (S26) and zinc oxide and eugenol cement (ZOE). Before and after filling, cavities were scanned by using micro-CT (SkyScan 1176). Filling and porosity were analyzed by using CTAn software. Filling ability was calculated based on volumetric percentage of the filled cavity. The number and percentage of closed pores were measured throughout entire extension of the filled cavity (total) and in each third (cervical, middle and apical), by using bi and tridimensional analyses. The filling data were submitted to ANOVA and Tukey statistical tests, and porosity data to Kruskall-Wallis and Dunn tests, at a 5% significance level. Result S26 and ZOE presented higher filling ability than MTA (p<0.05). S26 showed the highest total porosity (number and percentage) (p<0.05). In all thirds after 2D and 3D analyses, porosity was higher for S26 in comparison to MTA and ZOE (p<0.05). Conclusion Although Sealer 26 presented more porosity, the material was associated with a great filling ability. Micro-CT analysis showed no correlation between filling ability and porosity.

【摘要】
逆行充填腔的充填能力与孔隙率是根尖倒充填材料的重要性能指标，可通过微型计算机断层扫描（microcomputed tomography, micro-CT）进行评价。
本研究旨在采用微型计算机断层扫描（micro-CT）评估根尖倒充填材料的充填能力与孔隙率。
材料与方法：使用超声工作尖（CVD No. 6.1107-6）在牛牙本质切片上制备内径1 mm、深度3 mm的腔洞，分别采用三氧化矿物凝聚物（Mineral Trioxide Aggregate, MTA）、封闭剂26（Sealer 26, S26）以及氧化锌丁香油水门汀（zinc oxide and eugenol cement, ZOE）进行充填。充填前后均采用SkyScan 1176型微型计算机断层扫描设备对腔洞进行扫描，通过CTAn软件分析充填情况与孔隙特征。以充填腔的体积占比计算充填能力；通过二维及三维分析，测量充填腔整体及颈段、中段、根尖段的封闭孔隙数量与占比。充填数据采用方差分析（ANOVA）与Tukey多重比较检验进行统计分析，孔隙率数据采用克鲁斯卡尔-沃利斯（Kruskal-Wallis）检验与Dunn检验进行统计分析，显著性水准设定为5%。
结果：S26与ZOE的充填能力均显著高于MTA（p<0.05）；S26的总孔隙率（孔隙数量与占比）为三者最高（p<0.05）。二维与三维分析均显示，在颈段、中段、根尖段各分段中，S26的孔隙率均显著高于MTA与ZOE（p<0.05）。
结论：尽管封闭剂26的孔隙率更高，但其具备优异的充填能力；微型计算机断层扫描分析显示，充填能力与孔隙率之间无相关性。