Department of Endodontics, School of Dentistry and Dental Research Center, University of Medical Sciences, Mashhad, and Iranian Center for Endodontic Research, Shahid Beheshti University of Medical Sciences, Tehran, Iran.
J Endod. 2011 Dec;37(12):1613-8. doi: 10.1016/j.joen.2011.08.021. Epub 2011 Oct 13.
The purpose of the present study was the immunohistochemical study of fibronectin (FN) and tenascin (TN) in human tooth pulp capped with mineral trioxide aggregate (MTA) and novel endodontic cement (NEC) (calcium enriched mixture cement) after 2 and 8 weeks.
Thirty-two premolar teeth that were scheduled for extraction for orthodontic reasons were exposed and capped with either MTA or NEC. The teeth were randomly divided into 4 groups: group 1 (NEC for 2 weeks), group 2 (NEC for 8 weeks), group 3 (MTA for 2 weeks), and group 4 (MTA for 8 weeks). After capping the exposed pulps with either NEC (groups 1 and 2) or MTA (groups 3 and 4), half of the specimens underwent extraction and were prepared for histologic and immunohistochemical evaluation for FN and TN after 2 weeks, and the remaining half were assessed after 8 weeks. FN and TN expression was scored by a blinded pathologist on a scale of I-IV, and the results were analyzed by the Wilcoxon and Mann-Whitney U statistical tests.
FN and TN staining was observed in all 4 experimental groups, and there was no significant difference between expression of FN and TN in any groups. FN and TN staining was observed in the dentinal bridge matrix after 2 weeks under MTA. Expression of both markers reduced significantly after 8 weeks under MTA, and staining was observed only in unmineralized parts of dentinal bridge. FN and TN expression was observed in the matrix of the dentinal bridge after 2 weeks under NEC, and staining of both markers was reduced after 8 weeks compared with 2 weeks. The staining pattern of TN in NEC groups was higher than in MTA groups in both time intervals. However, the difference was not significant.
The present study demonstrated that both MTA and NEC are suitable biomaterials for direct pulp capping and are able to stimulate dentinal bridge formation. Moreover, the role of FN and TN as 2 major components of the matrix of a reparative dentinal bridge was observed.
本研究的目的是通过免疫组织化学方法研究在人牙髓中用矿物三氧化物聚合体（MTA）和新型根管封闭剂（NEC）（钙强化混合水泥）覆盖 2 周和 8 周后的纤维连接蛋白（FN）和腱生蛋白（TN）的表达。
32 颗因正畸需要而拔除的前磨牙，暴露牙髓后分别用 MTA 或 NEC 覆盖。将牙齿随机分为 4 组：组 1（NEC 覆盖 2 周）、组 2（NEC 覆盖 8 周）、组 3（MTA 覆盖 2 周）和组 4（MTA 覆盖 8 周）。用 NEC（组 1 和 2）或 MTA（组 3 和 4）覆盖暴露的牙髓后，一半的标本在 2 周后进行提取，用于 FN 和 TN 的组织学和免疫组织化学评估，另一半在 8 周后进行评估。FN 和 TN 的表达由一名盲法病理学家按 I-IV 级评分，结果采用 Wilcoxon 和 Mann-Whitney U 统计检验进行分析。
4 个实验组均观察到 FN 和 TN 的染色，各组 FN 和 TN 的表达无显著差异。MTA 覆盖 2 周后，牙本质桥基质中观察到 FN 和 TN 染色。MTA 覆盖 8 周后，两种标志物的表达均显著降低，仅在牙本质桥的未矿化部分观察到染色。NEC 覆盖 2 周后，牙本质桥基质中观察到 FN 和 TN 表达，8 周后与 2 周相比，两种标志物的染色均减少。在两个时间间隔内，NEC 组的 TN 染色模式均高于 MTA 组，但差异无统计学意义。
本研究表明，MTA 和 NEC 均适用于直接盖髓，能够刺激牙本质桥形成。此外，观察到 FN 和 TN 作为修复性牙本质桥基质的 2 种主要成分的作用。
