Effect of aging and cementation systems on the bond strength to root dentin after fiber post cementation

Abstract This study evaluated the effect of aging and cementation of fiber posts using glass ionomer and resin cements on push-out bond strength, failure mode, and resin tag formation. One hundred and twenty bovine incisors were used. After post-space preparation, the specimens were randomly allocated into 12 groups (n = 10) according to the cementation system used: GC - GC Gold Label Luting & Lining); RL - RelyX Luting 2; MC - MaxCem Elite; RU - RelyX U200 and the aging periods (24 hours, 6 months, and 12 months). Slices from the cervical, middle, and apical thirds were obtained and analyzed by push-out bond strength test and confocal laser scanning microscopy. One-way ANOVA and Tukey’s post-hoc test was used at a significance level of 5%. For the push-out bond strength test, no differences among GC, RU, and MC in the cervical and middle thirds were observed, regardless of the period of storage (P > 0.05). In the apical third, GC and RU showed similar bond strength but higher than other groups (P > 0.05). After 12 months, GC showed the highest bond strength (P < 0.05). Bond strength to post-space dentin decreased over time, regardless of the cementation system used. Cohesive failure was the most frequent, regardless of the period of storage, cementation system, and post-space third. Tag formation was similar among all groups. After 12 months, GC showed the highest bond strength values.

摘要 本研究评估了老化作用及使用玻璃离子水门汀（glass ionomer）与树脂水门汀（resin cements）粘接纤维桩（fiber posts）对推出粘结强度（push-out bond strength）、失效模式（failure mode）及树脂突形成（resin tag formation）的影响。本研究共使用120颗牛切牙（bovine incisors）。完成桩道预备（post-space preparation）后，根据所采用的粘接系统与老化周期，将标本随机分为12组（每组n=10）：粘接系统包括GC（GC Gold Label Luting & Lining）、RL（RelyX Luting 2）、MC（MaxCem Elite）、RU（RelyX U200），老化周期设置为24小时、6个月及12个月。从颈缘、根中及根尖三分之一段获取切片，通过推出粘结强度测试与共聚焦激光扫描显微镜（confocal laser scanning microscopy）开展分析。本研究采用单因素方差分析（one-way ANOVA）与Tukey事后检验（Tukey’s post-hoc test），显著性水平设定为5%。

推出粘结强度测试结果显示：无论存储周期如何，GC、RU与MC三组在颈缘、根中三分之一段的粘结强度均无显著差异（P>0.05）；在根尖三分之一段，GC与RU组粘结强度相近，且均显著高于其余各组（P>0.05）。老化12个月后，GC组粘结强度达到最高水平（P<0.05）。无论采用何种粘接系统，桩道牙本质的粘结强度均随时间推移逐渐下降。无论存储周期、粘接系统及桩道切片部位如何，内聚性失效（cohesive failure）均为最常见的失效模式。各组间树脂突形成情况无显著差异。老化12个月后，GC组的粘结强度数值最高。