Endodontic sealers and post-endodontic waiting time affect the bond strength of the fiber posts

Abstract Introduction The resistance adhesive of a fiber post can be affected by several factors, such as the endodontic sealer and post-endodontic waiting time. Objective The aim of this study was to evaluate the effect of different endodontic sealers and two different post-endodontic waiting times on the bond strength of fiber posts. Material and method Seventy-two bovine teeth were endodontically treated and filled using three endodontic sealers: eugenol-based, epoxy resin-based, or mineral trioxide aggregate-based. The specimens were stored at 37°C for 24 hours or for 30 months. After the respective storage times, the root canals were prepared for luting fiber posts using RelyX U200. Push-out tests and analysis of failures were performed. The push-out data were analyzed by two-way analysis of variance to compare the effects of the endodontic sealer and with the t-test to compare the effects of post-endodontic waiting time. Result The AH Plus sealer yielded the highest bond strength values at 30 months post-endodontics (11.26 Mpa) (p < 0.05), however no had difference with Endofill sealer at the same time. Endofill and MTA Fillapex sealers did not differ significantly in their effects, irrespective of the post-endodontic waiting time. Conclusion In conclusion, the endodontic sealer used and post-endodontic waiting time affect the adhesive resistance of fiber posts. The adhesion increases significantly when the fiber post is cemented 30 months after the root canal filling, while the adhesion is reduced when cementing immediately after root canal treatment, in particular for eugenol-based endodontic sealers.

摘要
引言：纤维桩（fiber post）的粘接阻力受多种因素影响，如根管封闭剂（endodontic sealer）及牙髓治疗后等待时间（post-endodontic waiting time）。
目的：本研究旨在评估不同根管封闭剂与两种牙髓治疗后等待时间对纤维桩粘接强度（bond strength）的影响。
材料与方法：选取72颗牛牙（bovine teeth），经牙髓治疗后分别采用三类根管封闭剂进行根管充填：丁香酚基型、环氧树脂基型以及矿物三氧化物凝聚体（mineral trioxide aggregate, MTA）基型。将标本分别于37℃下储存24小时或30个月。达到预设储存时间后，使用RelyX U200对根管进行粘结预备以粘结纤维桩。随后开展推出试验（push-out tests）与破坏模式分析。采用双因素方差分析（two-way analysis of variance）比较不同根管封闭剂的影响，采用t检验（t-test）比较不同牙髓治疗后等待时间的影响。
结果：牙髓治疗后30个月时，AH Plus封闭剂的粘接强度最高（11.26 MPa，p<0.05），但同期与Endofill封闭剂无显著差异；无论牙髓治疗后等待时间长短，Endofill与MTA Fillapex封闭剂的粘接效果均无显著差异。
结论：综上，所选用的根管封闭剂及牙髓治疗后等待时间均会影响纤维桩的粘接阻力。在根管充填后30个月再行纤维桩粘结时，粘接强度可显著提升；而在牙髓治疗后即刻进行粘结，尤其是使用丁香酚基型根管封闭剂时，粘接强度会出现明显下降。