研究比较ProTaper Next（PTN）、K3XF和HyFlex CM（HF）3种热处理镍钛机动系统预备弯曲根管至不同工作宽度时的根尖碎屑推出情况及预备效率。

收集未行根管治疗、牙根完整、根尖发育完全、无牙根内外吸收或根管钙化的恒磨牙，选择弯曲度为20°~ 45°、初尖锉号数为10^#的独立根管72个，按照镍钛系统（PTN、K3XF、HF）随机分为3组，每组再按工作宽度（25^#、30^#、40^#）分为3个亚组（n= 8）。记录各组完成根管预备的时间，收集并称量各组推出根尖孔的牙本质碎屑量。采用单因素方差分析对数据进行统计分析，Tukey post hoc test进行两两比较。

PTN预备根管至25^#、30^#、40^#时的碎屑推出量分别为（0.37 ± 0.09）、（0.43 ± 0.14）、（0.42 ± 0.15）mg，K3XF预备至25^#、30^#、40^#时的碎屑推出量分别为（0.47 ± 0.13）、（0.50 ± 0.16）、（0.47 ± 0.15）mg，HF预备至25^#、30^#、40^#时的碎屑推出量分别为（0.88 ± 0.19）、（0.91 ± 0.20）、（0.80 ± 0.15）mg。预备至同一工作宽度时，HF组根尖碎屑推出量大于PTN组和K3XF组（F₂₅= 28.700，P₂₅<0.001；F₃₀ = 19.292，P₃₀<0.001；F₄₀= 15.190，P₄₀<0.001）。终末工作宽度增大时，3种镍钛系统的碎屑推出量均无显著增加（P>0.05）。预备根管至25^#和30^#时，3组器械预备时间差异无统计学意义（P>0.05）。预备至40^#，PTN组用时[（173.1 ± 18.0）s]比K3XF组[（220.5 ± 29.7）s]和HF组[（227.6 ± 22.3）s]少，差异具有统计学意义（F= 12.369，P= 0.001）。

与HF相比，PTN和K3XF预备弯曲根管时碎屑推出较少。当预备至较大工作宽度时，PTN的预备效率较高。

To evaluate the efficiency and amount of apically extruded debris when preparing curved root canal to different apical working width using ProTaper Next (PTN) , K3XF and HyFlex CM (HF) .

Extracted molars meeting the following criteria were collected: without root canal treatment, mature apex, without root resorption and calcification. Seventy-two canals with the curvature between 20 and 45 degrees and apical patency with a size 10 K-file were recruited in this study. The canals were randomly assigned to 3 groups according to the instruments (PTN, K3XF, HF) . Each group were divided into 3 subgroups based on the apical working width (size 25, 30, 40) . The apically extruded debris of each group were collected and dried in preweighted centrifugal tubes, and then assessed with an electronic balance. The total time required to complete root canal preparation was also recorded. The level of significance was determined by One-Way ANOVA followed by Tukey post hoc test for a multiple comparison procedure.

The amount of apical debris of PTN in three subgroups (size 25, 30, 40) were (0.37 ± 0.09) , (0.43 ± 0.14) , (0.42 ± 0.15) mg respectively. As for K3XF, the debris weight of three subgroups were (0.47 ± 0.13) , (0.50 ± 0.16) , (0.47 ± 0.15) mg respectively. And about HF, the debris weight of three subgroups were (0.88 ± 0.19) , (0.91 ± 0.20) , (0.80 ± 0.15) mg respectively. HF extruded significantly more debris than PTN and K3XF at the same apical working width (F₂₅= 28.700, P₂₅<0.001; F₃₀= 19.292, P₃₀<0.001; F₄₀= 15.190, P₄₀<0.001) . No significant differences were found related to the apical working width (P>0.05) . The instrumentation time with PTN which was (173.1 ± 18.0) s showed significantly shorter time than K3XF with (220.5 ± 29.7) s and HF with (227.6 ± 22.3) s at apical working width of size 40 (F= 12.369, P= 0.001) . But no significant differences were found among three rotary systems at apical working width of size 25 and 30 (P>0.05) .

In the preparation of curved root canals, HF extruded significantly more debris than PTN and K3XF. PTN was faster than K3XF and HF when canals were prepared to a large apical size.