Department of Cariology and Endodontology, Peking University School and Hospital of Stomatology, Beijing, China.
Dental Clinic, Peking University International Hospital, Beijing, China.
Int Endod J. 2019 Mar;52(3):371-376. doi: 10.1111/iej.13005. Epub 2018 Oct 5.
To evaluate the recovery effect of proanthocyanidin (PA) on microtensile bond strength (μTBS) to sodium hypochlorite (NaOCl)-treated dentine.
Fifty-five freshly extracted third molars with intact dental crowns, no caries or restorations were sectioned to expose a sound middle layer of dentine and were randomly divided into 11 groups. In the blank control group, dentine surfaces were immersed in deionized water for 20 min. In the negative control group, dental surfaces were immersed in 5.25% NaOCl for 20 min. In the other nine experimental groups, after immersion for 20 min in 5.25% NaOCl, followed by PA (5%, 10%, or 15%) treatment for 1, 5 min or 10 min. The NaOCl solution was renewed every 5 min. Then dentine surfaces were bonded using SE bond. Bonded samples were sectioned into dentine-resin sticks (n = 45) for microtensile bond strength testing (MPa). Failure modes were observed and classified into three types with a stereomicroscope. Microtensile bond strength data were analysed using one-way anova. The confidence interval test was performed to analyse the recovery effect of PA on bond strength to NaOCl-treated dentine. The chi-squared test was used to analyse failure mode distribution.
After use of 5.25% NaOCl for 20 min, microtensile bond strength in the negative control group decreased significantly compared with that of the untreated group (P < 0.05). After a recovery treatment of 10% PA for 10 min or 15% PA for more than 5 min, the bond strength was restored to at least 90% of baseline (P < 0.05). No recovery effect on bond strength was detected after the application of 5% PA for 1 min (P > 0.05). Adhesive fracture was found to be the most common failure mode in the NaOCl-treated group. After the recovery application of PA, the proportion of mixed failures increased significantly (P < 0.05).
Microtensile bond strength to NaOCl-treated dentine recovered after the application of either 5% PA for more than 5 min or 10% or 15% PA for more than 1 min. The application of PA before an adhesive procedure may immediately restore the compromised bond strength of NaOCl-treated dentine.
评估原花青素（PA）对次氯酸钠（NaOCl）处理牙本质的微拉伸粘结强度（μTBS）的恢复效果。
将 55 颗新鲜拔出的第三磨牙用完整的牙冠进行切割，暴露出一个完整的中层牙本质，并将其随机分为 11 组。在空白对照组中，牙本质表面用去离子水浸泡 20 分钟。在阴性对照组中，牙本质表面用 5.25% NaOCl 浸泡 20 分钟。在其他 9 个实验组中，用 5.25% NaOCl 浸泡 20 分钟后，再用 5%、10%或 15% PA 处理 1、5 分钟或 10 分钟。每 5 分钟更换一次 NaOCl 溶液。然后用 SE 胶将牙本质表面粘结。将粘结样本切割成牙本质-树脂棒（n=45）进行微拉伸粘结强度测试（MPa）。用体视显微镜观察并将破坏模式分为三种类型。用单因素方差分析对微拉伸粘结强度数据进行分析。置信区间检验用于分析 PA 对 NaOCl 处理牙本质粘结强度的恢复效果。卡方检验用于分析破坏模式的分布。
用 5.25% NaOCl 处理 20 分钟后，阴性对照组的微拉伸粘结强度明显低于未处理组（P<0.05）。用 10% PA 处理 10 分钟或 15% PA 处理 5 分钟以上，粘结强度可恢复至基线的至少 90%（P<0.05）。用 5% PA 处理 1 分钟对粘结强度无恢复效果（P>0.05）。在用 NaOCl 处理的组中，发现以黏附性断裂为最常见的破坏模式。用 PA 恢复处理后，混合性破坏的比例明显增加（P<0.05）。
用 5% PA 处理 5 分钟以上或用 10%、15% PA 处理 1 分钟以上，均可恢复 NaOCl 处理牙本质的微拉伸粘结强度。在粘结程序之前使用 PA 可能会立即恢复 NaOCl 处理牙本质受损的粘结强度。
