iRoot SP牙本质小管渗透性的研究

Penetration of Dentinal Tubules by iRoot SP in Extracted Teeth in Vitro

目的:通过扫描电镜评价iRoot SP牙本质小管渗透性。方法:单根管下颌前磨牙28颗截冠保留牙根14mm,机扩备根管至F2,随机数字表法将标本分为实验组(A、B组,n=12)和对照组(n=4)。A组:iRoot SP+热牙胶充填;B组:AH Plus+热牙胶充填。实验组样本取冠、中、尖横截面,对照组样本取根管纵切面,SEM观察,实验组测量根管封闭剂在牙本质小管的渗透深度,对照组观察牙本质小管玷污层的去除程度。结果:实验组中,在根尖部AH Plus较iRoot SP牙本质小管渗透深度长,两者有显著差异(P<0.05),在根管冠部、中部两者渗透深度相当,无统计学意义。对照组中,根管中上段牙本质小管口明显开放,玷污层基本去除,根尖段,有玷污层未完全去除。结论:iRoot SP与AH Plus相比,后者牙本质小管渗透性更强;两者在根管中上段渗透性高于根尖部;玷污层在一定程度上影响了根管封闭剂的渗透性。

Objective：To evaluate the penetration depth of iRoot SP in the dentinal tubules by scanning electron microscopy（SEM）.Methods：Twenty-eight mandibular premolars with single canal were decoronated to obtain 14-mm root segments.The root canals were instrumented using Protaper files prepared to F1.Roots were randomly divided into 2experimental groups（A and B,n=12）and control group（n=4）.Specimens of group A were filled with iRoot SP using the continuous wave of condensation technique.Specimens of group B were filled with AH Plus using the same technique.Specimens of group A and group B were transversely sectioned.The sealers penetration depth into the dentinal tubules was observed and measured in the coronal,middle and apical third of the root canal using SEM.Specimens of control group were longitudinally sectioned and the dentinal tubules were observed.Results：The penetration depth of AH Plus group was significantly higher than that of iRoot SP group in the apical third of the root canal walls（P〈0.05）.There was no significant difference in the coronal and middle third of the root canal walls between two groups.The smear layer was almost completely removed in the coronal and middle third of the root canal walls,however,partly removed in the apical third of the root canal walls.Conclusion：The dentinal tubule penetration of AH Plus is significantly greater than that of iRoot SP.The penetration depth of AH Plus and iRoot SP was better in the coronal and middle third than in the apical third of the root canal walls.The dentinal tubule penetration of sealers is affected by their physical and chemical properties and smear layer.