弯曲根管用镍钛器械预备后根管偏移的研究

A comparison of apical deviation of curved canals with Nickel-titanium instruments

目的:研究3种镍钛根管预备器械预备后牙弯曲根管产生根管偏移的情况。方法:选择48个弯曲度>25°的下颌第一、二磨牙近中根包埋于Branmante模型中,分别用机动Hero642、Profile和手用ProTaper、不锈钢K锉进行根管预备。拍摄根管预备前后根尖、根中段横截面的影像,测定根管偏移的量、方向和轴中心率。结果:Hero642和Profile在根尖段和根中段根管的偏移显著小于不锈钢K锉,手用ProTaper仅在根尖段小于不锈钢K锉; 3种镍钛器械的轴中心率均低于不锈钢K锉,而镍钛器械组间无显著性差异;镍钛器械和不锈钢器械在根尖段根管中心偏向近中侧,而在根中段不锈钢K锉和手用ProTaper根管中心多数偏向远中侧,与Hero642和Profile有显著性差异。结论:Hero642、Profile和ProTaper在预备弯曲根管时有较小的偏移及良好的中心定位作用,尤其是Hero642和Profile对根尖和根中段成形能力较佳。

AIM: To investigate the apical deviation of curved canals in posterior teeth using three nickel-titanium instruments. METHODS: Mesial roots of mandibular first or second molars were mounted in resin using Bramant system and cross-sectioned in the apical and mid-root areas. Canals were prepared with nickel-titanium instruments(Hero 642,Profile or ProTaper)or stainless steel K-files. The pre- and post-instrumented images of the sections were recorded to measure the apical deviation and centering ratio. RESULTS: A significant difference was found between Hero 642,Profile and stainless steel K-file in the apical and mid-section.ProTaper showed less deviation only in the apical section. The centering ratio was lower in three nickel-titanium instruments than in stainless steel K-file.The majority of the root centers in the stainless steel K-file and ProTaper were deviated to the distal direction compared with Hero 642 and Profile. CONCLUSION: Hero 642,Profile and ProTaper resulted in relatively good ability in preserving the canal center in curved canals and less deviation,especially Hero 642 and Profile exhibited better shaping ability in apical and mid-root areas.