酸蚀处理对根尖倒充填材料封闭性的影响

目的：评估酸蚀处理倒预备洞型对根尖倒充填材料封闭性能的影响。方法：选用80颗新鲜拔除的下颌磨牙，使用3.5倍放大镜检查，排除牙根隐裂，清洁干净后保存于蒸馏水中备用,截取其远中根，行根管治疗。根管预备使用旋转镍钛器械，根管充填采用冷侧压法。根管治疗后牙根截去根尖3 mm，使用超声尖倒预备（3 mm深）。倒预备后牙根随机分成4组，分别使用银汞、临时充填材料（intermediate restorative material, IRM）、新型根尖倒充填材料iRoot BP Plus和三氧化矿物凝聚体（mineral trioxide aggregate, MTA）4种材料倒充填。每组再根据倒预备洞型行酸蚀处理与否分为酸蚀组和非酸蚀组两个亚组，每组10颗牙。牙根倒充填后使用藻酸盐印膜材覆盖根尖，保存在PBS溶液中1周，待其固化，使用亚甲基蓝染色1周，取出纵行劈开，在体视显微镜下观察微渗漏。统计学分析采用单因素方差分析和Tamhane’s T2 法，α值设为0.05。结果：各组渗漏值为：银汞酸蚀（2.80 ± 0.72） mm，银汞不酸蚀（2.07 ± 0.86） mm，IRM 酸蚀（1.54 ± 0.19） mm，IRM 不酸蚀（1.12 ± 0.28） mm，iRoot BP Plus 酸蚀（0.20 ± 0.20） mm，iRoot BP Plus 不酸蚀（0.11 ± 0.08） mm，MTA 酸蚀（0.19 ± 0.19 ）mm，MTA 不酸蚀（0.17 ± 0.14） mm。单因素方差分析显示不同组渗漏差异有统计学意义。Tamhane’s T2 法组间比较显示：iRoot BP Plus组和MTA组渗漏显著小于银汞和IRM组（P<0.05）；iRoot BP Plus组和MTA组渗漏无显著差别；酸蚀会增加IRM的渗漏性（P<0.05）；酸蚀对MTA、iRoot BP Plus和银汞的渗漏性无显著影响。结论：酸蚀处理不能改进根尖倒充填材料的封闭性。

Effect of acid etching of retropreparation cavities on seal of retrofill materials

Objective: To evaluate the effect of acid etching of retropreps on seal of different retrofill materials. Methods: In the study, 80 freshly extracted lower molar teeth were used. They were examined under 3. 5 x magnifying glass to rull out fractures. They were cleaned and stored in distilled water before use. The distal roots were sectioned off and underwent root canal treatment. Rotary nickel-titanium instruments were used during instrumentation and the roots were obturated using lateral condensation technique. The apical portion (3 mm in length) was removed with a fine grit diamond bur, the root tip was retroprepared with a ultrasonic tip (3 mm in depth). The retroprepared roots were randomly assigned to 4 groups and retrofilled with amalgam,intermediate restorative material (IRM), iRoot BP Plus and mineral trioxide aggregate (MTA). The groups were further divided into subgroups according to treatment of the root end cavity (etch and non-etch). The root tips were covered with alginate impression material and were left to set in PBS solution for a week and stained with methylene blue for a week. The roots were removed from the dye solution,thoroughly rinsed and dried,split in halves along the long axis with a diamond disk and observed under a stereoscope. The linear dye leakage was measured and analyzed. One way ANOVA and Tamhane's T2 method were used to analyze the data. The significance level was set at 0.05. Results: The dye leakage results (mean ± standard deviation) according to the treatment groups were: amalgam etch (2. 80 ±0.72) mm, amalgam non-etch (2. 07 ±0.86) mm, IRM etch (1.54 ± 0.19) mm, IRM non-etch (1.12 ±0.28) mm,iRoot BP Plus etch (0.20 ±0.20) mm, iRoot BP Plus non-etch (0. 11 ±0.08) mm, MTA etch (0. 19 ±0. 19) mm, and MTA non-etch (0. 17 ±0. 14) mm. One way ANOVA showed significant differences between the groups. Comparison between the groups using Tamhane's T2 method showed roots retrofilled with iRoot BP Plus and MTA had significant less leakage than those retrofilled with amalgam and IRM (P <0.05); There was no significant difference in terms of leakage between iRoot BP Plus and MTA; Acid etching increased leakage of IRM but did not affect MTA, iRoot BP Plus or amalgam retrofillings. Conclusion: Acid etching is not shown to benefit apical sealing of retrofill materials.