次氯酸钠配合SmearClear清除根管玷污层的研究

目的:比较4种根管冲洗方法清除根管玷污层的效果,研究出有效去除根管玷污层的方法。方法:20个无龋单根前牙随机分为4组,A组:60℃30 g/L次氯酸钠液加170 g/L EDTA,#15K锉提拉冲洗;B组:60℃30 g/L次氯酸钠液加SmearClear,#15K锉提拉冲洗;C组:60℃30 g/L次氯酸钠液加170 g/LEDTA液超声荡洗;D组:60℃30 g/L次氯酸钠液加SmearClear超声荡洗。扫描电镜下放大2 500倍和4 000倍观察根尖1/3、根中1/3和根上1/3玷污层清除情况。按照根管壁玷污层清除情况和根管壁腐蚀程度的分级标准进行统计学分析。结果:①根管壁玷污层清除情况:4组在根上2/3区玷污层均有效去除,各组间差异无统计学意义(P>0.05),B组根尖1/3基本无玷污层,A、C、D组仅见少部分玷污层被去除,B组与A、C、D组差异有统计学意义(P<0.05);②根管壁腐蚀性比较:C、D组根上2/3区腐蚀度较大,而A、B组未见明显腐蚀。C、D组与A、B组相比差异有统计学意义(P<0.05),各组根尖1/3根管壁腐蚀度差异无统计学意义(P>0.05)。结论:SmearClear与60℃30 g/L次氯酸钠液联合应用能更有效的去除根管玷污层,且对根管壁表面结构无明显破坏。

Effects of NaOCl combined with SmearClear on removal of the smear layer

AIM:To assess,by scanning electron microscopic(SEM) analysis,the ability of SmearClear plus ultrasonic irrigation in the removal of the smear layer from the human root canal system.METHODS:Based on the irrigating solution and the technique used,twenty single-rooted human anterior teeth were divided randomly into four groups.Samples were irrigated with 60℃ 30g/L NaOCl after different instrumentation: group A(60℃ 30g/L NaOCl +170g/L EDTA agitating with #15 K File),group B(60℃ 30g/L NaOCl + SmearClear agitating with #15 K File),group C(60℃ 30g/L NaOCl + 170g/L EDTA with ultrasonic irrigation),and group D(60℃ 30g/L NaOCl + SmearClear with ultrasonic irrigation).After final irrigation,teeth were prepared for SEM analysis to evaluate the cleaning of the coronal,middle and apical thirds of radicular dentin by determining the presence or absence of smear layer and the erosion of the dentin canal.The data was statistically analyzed using the analysis of variance test.RESULTS: ①Smear layer: At the coronal and middle thirds,there was no significant difference.All of them were equally efficient in the removal of smear layer.At the apical third,SmearClear showed significantly better smear layer removing ability than EDTA.②Erosion: At the coronal and middle thirds,there was significant difference between group C,D and group A,B.Ultrasonic groups showed more significant erosion than the others.There was no statistical difference among the four groups.CONCLUSION:Irrigation with 60℃ 30g/L NaOCl combinated with SmearClear is more efficient than that with 170g/L EDTA in the removal of smear layer from the root canal system,which does not cause lesion on dentin canals.