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目的比较ProTaper和K3镍钛预备系统预备根管对牙根抗折载荷的影响。方法 30颗完整的离体单根恒牙根管预备后随机分成三组,两个实验组分别采用ProTaper和K3镍钛预备系统预备根管,对照组采用不锈钢K锉逐步后退法预备根管,三组均采用冷牙胶侧压充填根管。将标本用万能试验机垂直加载直至标本发生纵裂,记录牙根纵裂时的最大抗压载荷和纵裂的类型。结果两个实验组的平均抗压载荷值分别是206.05±73.31N和210.04±64.57N,两个实验组之间无明显统计学差异。对照组平均抗压载荷值(269.10±56.64N)高于两实验组,但差异不具有统计学意义。83.3%的牙根纵裂线发生于颊舌方向。结论相比传统的逐步后退法,ProTaper和K3大锥度镍钛器械预备不会明显降低牙根的最大抗压载荷。以上两种镍钛预备技术对牙根抗压载荷的影响无区别。
Objective To compare the effect of ProTaper and K3 NiTi preparation system on root bending resistance. Methods Thirty intact single root canal permanent teeth were prepared and divided into three groups randomly. The two groups were prepared with ProTaper and K3 NiTi preparation system respectively. The control group was prepared with K- Three groups were using cold-pressure plastic lateral root canal filling. The specimens were loaded vertically with a universal testing machine until the specimens were longitudinally split and the maximum compressive load and the type of longitudinal cracks were recorded. Results The average compressive load values of the two experimental groups were 206.05 ± 73.31N and 210.04 ± 64.57N, respectively. There was no significant difference between the two experimental groups. The mean compressive load of control group (269.10 ± 56.64N) was higher than that of the two experimental groups, but the difference was not statistically significant. 83.3% of the longitudinal root fracture line occurs in the buccolingual direction. CONCLUSIONS ProTaper and K3 large-taper NiTi devices do not significantly reduce the maximum compressive load on the root compared to the traditional step-down approach. The above two NiTi preparation techniques have no difference on the root compression load.