From the Department of Endodontics, School of Stomatology, Tianjin Medical University, #12 Qi Xiang Tai Road, He Ping District, Tianjin 300070, PR China.
BMC Oral Health. 2014 Sep 8;14:114. doi: 10.1186/1472-6831-14-114.
Efforts to improve the efficacy of smear layer removal by applying irrigant activation at the final irrigation or by elevating the temperature of the irrigant have been reported. However, the combination of such activation protocols with 60 °C 3% sodium hypochlorite (NaOCl) has seldom been mentioned. The aim of this study was to compare the efficacy in smear layer removal of four different irrigation techniques combined with 60 °C 3% NaOCl and 17% EDTA.
Fifty single-rooted teeth were randomly divided into five groups (n = 10) according to the irrigant agitation protocols used during chemomechanical preparation(Dentsply Maillefer, Ballaigues, Switzerland): a side-vented needle group, a ultrasonic irrigation (UI) group, a NaviTip FX group, an EndoActivator group, and a control group (no agitation). After each instrumentation, the root canals were irrigated with 1 mL of 3% NaOCl at 60 °C for 1 minute, and after the whole instrumentation, the root canals were rinsed with 1 mL of 17% EDTA for 1 minute. Both NaOCl and EDTA were activated with one of the five irrigation protocols. The efficacy of smear layer removal was scored at the apical, middle and coronal thirds. The Data were statistically analyzed using SAS version 9.2 for Windows (rank sum test for a randomised block design and ANOVA).
No significant differences among the NaviTip FX group, EndoActivator group and control groups, and each of these groups showed a lower score than that of UI group (P < 0.05). Within each group, all three thirds were ranked in the following order: coronal > middle > apical (P < 0.05). In the coronal third, the NaviTip FX group was better than UI group. In the middle and apical third, the differences were not significant among any of the groups.
Even without any activation, the combination of 60 °C 3% NaOCl and 17% EDTA could remove the smear layer effectively, similar to NaviTip FX or EndoActivator, and these three protocols were more effective than UI. However, regardless of different types of irrigation technique applied, complete removal of the smear layer was not achieved, particularly in the apical third.
为提高冲洗液的效能，已有研究尝试在终末冲洗阶段应用冲洗液激活剂或提高冲洗液温度。然而，将这些激活方案与 60°C 3%次氯酸钠（NaOCl）联合应用的报道较少。本研究旨在对比 4 种不同冲洗技术联合 60°C 3%NaOCl 和 17%EDTA 对玷污层去除效果的影响。
50 颗单根牙随机分为 5 组（n = 10），根据化学机械预备过程中使用的冲洗液搅拌方案分组：侧孔冲洗针组、超声冲洗（UI）组、NaviTip FX 组、EndoActivator 组和对照组（无搅拌）。每次器械预备后，用 1 mL 60°C 的 3%NaOCl 冲洗 1 分钟，整个预备完成后，用 1 mL 17%EDTA 冲洗 1 分钟。两种 NaOCl 和 EDTA 均使用 5 种冲洗方案中的一种进行激活。在根尖、中 1/3 和冠 1/3 处评估玷污层去除效果。采用 SAS 9.2 for Windows 软件（随机区组设计秩和检验和 ANOVA）进行数据统计分析。
NaviTip FX 组、EndoActivator 组和对照组之间无显著差异，且这 3 组的评分均低于 UI 组（P < 0.05）。同一组内，3 个部位的评分均为：冠部 > 中部 > 根尖部（P < 0.05）。在冠部，NaviTip FX 组优于 UI 组。在中 1/3 和根尖部，各组之间无显著差异。
即使不进行任何激活，60°C 3%NaOCl 和 17%EDTA 联合应用也能有效去除玷污层，效果类似于 NaviTip FX 或 EndoActivator，这 3 种方案均优于 UI。然而，无论应用何种冲洗技术，玷污层均不能完全去除，尤其是根尖部。
