Tabrizizadeh Mehdi, Dabbagh Mohammad Mahdi, Badrian Hamid, Davoudi Amin
Associate Professor, Department of Endodontics, Faculty of Dentistry, Shahid Sadoughi University of Medical Sciences, Yazd, Iran.
Post Graduate Student, Department of Endodontics, School of Dentistry, Shahid Sadoughi University Medical Sciences, Yazd, Iran.
J Int Oral Health. 2015 Sep;7(9):36-9.
Providing an apical stop in open apex roots is one of the endodontic challenges. The aim of present study was to compare the surface hardness of both mineral trioxide aggregate (MTA) and calcium-enriched mixture (CEM) cement at different setting situations.
A total of 40 freshly extracted human teeth with a single root and normal apex and no obvious caries or curvatures were selected. The teeth were sectioned horizontally from the cement enamel junction and 2 mm above the apex. Standard technique was administered for cleaning and shaping of the canals. Open apex root canal was prepared by using Peso reamer. The prepared teeth were randomly divided into four groups in which two groups were filled by MTA and the other groups were filled by CEM. White MTA and CEM cement plugs were prepared and condensed up to the apical end. In two groups, moistened paper point was placed in the canals and in the other group dried paper points was used. Vickers test was done to evaluate the microhardness and the collected data were analyzed by Kruskal-Wallis and three-way ANOVA tests using SPSS software version 18 at a significant level of 0.05.
The highest and lowest surface hardness was observed in CEM group at dried condition with 4 mm thickness indentation (145.10 ± 7.60 kg/mm(2)) and moist MTA group indented at 8 mm thickness (111.25 ± 5.37 kg/mm(2)). However, no significant difference was noticed (P > 0.05).
Humidity condition might not influence the microhardness properties of both MTA and CEM cement apical plugs at different tested indentation thickness.
为开放根尖的牙根提供根尖止点是牙髓病治疗中的挑战之一。本研究的目的是比较不同凝固情况下矿物三氧化物凝聚体（MTA）和富钙混合物（CEM）水泥的表面硬度。
共选取40颗新鲜拔除的单根、根尖正常、无明显龋坏或弯曲的人牙。将牙齿从牙骨质釉质界水平切断，并在根尖上方2mm处切断。采用标准技术对根管进行清理和成形。使用Peso扩孔钻制备开放根尖根管。将制备好的牙齿随机分为四组，其中两组用MTA充填，另外两组用CEM充填。制备白色MTA和CEM水泥桩并向根尖端加压充填。两组在根管内放置湿纸尖，另一组使用干纸尖。进行维氏试验以评估显微硬度，并使用SPSS 18.0软件通过Kruskal-Wallis和三因素方差分析对收集的数据进行分析，显著性水平为0.05。
在干燥条件下4mm厚度压痕的CEM组观察到最高表面硬度（145.10±7.60kg/mm²），在湿MTA组8mm厚度压痕时观察到最低表面硬度（111.25±5.37kg/mm²）。然而，未发现显著差异（P>0.05）。
在不同测试压痕厚度下，湿度条件可能不会影响MTA和CEM水泥根尖桩的显微硬度特性。
