根管充填糊剂根尖封闭性的体外研究

目的：体外评价3种根管充填糊剂的根尖封闭效果。方法选取人离体下颌前磨牙68颗，截冠后随机分为A、B、C、D、E、F 6个组，其中A、B、C、D为实验组（每组12颗牙齿），E和F分别为阳性和阴性对照组（每组各10颗牙齿），所有样本均使用K3镍钛器械采用冠向下法完成根管预备后按如下方法进行根管充填：A、B组分别用树脂类根管充填糊剂AH Plus和生物陶瓷类根管充填糊剂iRoot SP行冷牙胶侧方加压充填；C、D组分别用生物陶瓷类根管充填糊剂iRoot SP和硅酮类根管充填糊剂Guttaflow行单尖充填；E、F组不添加糊剂只用牙胶尖侧方加压充填。将完成根管充填的实验组（每组10颗）和对照组浸入印度墨水中染色，其中4个实验组和阳性对照组在根尖孔周围2mm以外的牙体表面涂布2层指甲油，阴性对照组则在整个牙根表面涂布2层指甲油，采用透明牙法观察根尖微渗漏情况，使用imageJ软件测量并记录染色长度，并进行统计学分析；将剩余的样本横切后用扫描电镜对其截面进行观察。结果4个实验组所获得的浸墨长度分别为：A（1.02±0.46）mm, B（1.05±0.42）mm, C（1.02±0.45）mm, D（1.16±0.43）mm。4组浸墨长度之间的差异均无统计学意义（P〉0.05）。扫描电镜观察各组根管充填糊剂和根管壁牙本质之间均有缝隙。结论3种根管充填糊剂均不能完全封闭根管，在根尖封闭效果上无明显差异。

In vitro study of the sealing ability of root canal sealers

Objective To evaluate the sealing ability of three root canal sealers（AH-Plus、iRoot SP and GuttaFlow）. Methods Sixty-eight extracted single-rooted human mandibular premolars were randomly divided into 6 groups including four test groups （named A、B、C、D） （n=12） and a positive control group （named E） （n=10） and a negative control （named F） （n=10）. All teeth were prepared by crown-down techniques with K3 Nickel-Tita-nium files. After that, all root canals were obturated as follows：group A and group B were filled with Resin-based sealers AH-Plus and biocompatible ceramic sealers iRoot SP respectively using a lateral condensation technique;group C and group D were filled with biocompatible ceramic sealers iRoot SP and Silicone-based sealers Gutta-flow respectively using a single cone technique;group E and group F （the control groups ） were filled with gutta-percha without any sealer using a lateral condensation technique. All samples were immersed in indian ink to be stained. Among these samples, the root surface in experimental and positive control groups were coated with nail＆amp;nbsp;polish except for the apical 2mm, and the whole root surface in negative control group was coated with two layers of nail polish. The micro-leakage of the 6 groups was evaluated by dye penetration with the transparent method. The length of dye penetration was measured with image J under the stereograph microscope. The data was ana-lyzed using ANOVA;the remaining teeth were sectioned and examined under scanning electron microscope （SEM） to observe the micro-structure. Results The mean length of dying line of four test groups were 1.02± 0.46mm,1.05±0.42mm,1.02±0.45mm and 1.16±0.43mm, respectively. There is no significant difference among each group in the length of dying line （P〉0.05）. SEM revealed there was gap between the dentinal walls and the filling paste in each group. Conclusion Three root canal sealers do not completely fill the root canal system and the sealing ability of