两种镍钛系统预备根管对牙根抗折强度的影响

Influence of two Ni-Ti instrumentation techniques on fracture resistance of endodontically treated roots

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 influence of root canal preparation using K3 and ProTaper Ni-Ti instruments on the fracture resistance of endodontically treated roots.Methods Thirty extracted single-rooted mandibular teeth were randomly divided into three groups according to the preparation instrument used： K3 group,ProTaper group and control group with stainless steel K-file.The root canals of three groups were filled by cold lateral condensation with gutta-percha and AH-plus sealer.The specimens were loaded to root fracture.The fracture pattern was evaluated using an optical stereomicroscope and the location of the failure was recorded.Results The mean values of fracture loads of the K3 group and ProTaper group is 206.05±73.31N and 210.04±64.57N respectively.The control group displayed higher mean values of fracture loads（269.10±56.64N） than the K3 group and ProTaper group,but no significant difference was found（P0.05）.83.3 percent of root fracture lines were found in the buccolingual direction.Conclusion Preparation with K3 or ProTaper files did not significantly reduce the in vitro fracture resistance of endodontically treated roots compared with K file.The fracture resistance after preparation with K3 and ProTaper files did not differ significantly.