预加载疲劳应力对R-相镍钛锉表面形态及疲劳折断性能的影响

发布时间：2018-05-30 11:41

  本文选题：预加载应力 + 疲劳折断　； 参考：《口腔医学研究》2017年08期

【摘要】：目的:比较K3XF和K3经过预加载疲劳应力后的表面形态和疲劳折断性能。方法:25 mm长、25#/0.06锥度的K3XF和K3各48支,随机分为4组(n=12),组1不做预加载。组2~组4分别使用60°弯曲角度、3.5mm弯曲半径的模拟金属根管预加载疲劳应力5s、10s、20s。每组随机选取2支锉在SEM下观察表面形态,其余10支锉使用上述模拟根管进行疲劳折断实验。记录疲劳折断时间,计算疲劳折断圈数;测量折断段长度,并对折断断口进行SEM观察。SAS 9.3软件进行双因素的方差分析,显著性水平0.05。结果:SEM见两种根管锉弯曲最大处的切割刃明显磨损、出现大量裂纹、边缘不整齐。K3XF表面缺陷明显少于K3。K3XF预加载疲劳应力20s后的疲劳折断圈数从新锉的(210±59)降低为(156±37),差异有显著性(P0.05)。K3预加载疲劳应力5s、10s、20s后的疲劳折断圈数从新锉的(145±38)分别降低为(110±27)、(101±31)和(62±31),5s和10s组无显著差异,其余两两之间差异有显著性(P0.05)。结论:K3XF对预加载疲劳应力的抵抗性优于K3。
[Abstract]:Aim: to compare the surface morphology and fatigue fracture properties of K3XF and K3 after pre-loading fatigue stress. Methods 48 K3XF and K3 with the taper of 25 #10 / 0.06 were randomly divided into 4 groups, without preloading in group 1. Group 2 ~ 4 used simulated metal root canal pre-loading fatigue stress of 5s10 ~ 10s ~ 20s with 60 掳bending angle and 3.5 mm bending radius respectively. In each group, two files were randomly selected to observe the surface morphology under SEM, and the other 10 files were tested for fatigue fracture using the simulated root canal mentioned above. The fatigue fracture time was recorded, the number of fatigue fracture circles was calculated, the length of fracture segment was measured, and the SEM observation. SAS9.3 software was used to analyze the variance of two factors. The significant level was 0.05. The results showed that the cutting edge of the two kinds of root canal file had obvious wear and tear and a large number of cracks appeared in the maximum bend of the root canal file. The number of fatigue broken rings decreased from 210 卤59 to 156 卤37 when the surface defects of K3XF were obviously less than those of K3.K3XF preloaded fatigue stress 20s. The difference was significant after pre-loading fatigue stress of 5s ~ 10s ~ 20 s. The number of fatigue broken rings was 145 卤38 from the new file. There was no significant difference between 10 s and 10 s groups. There was significant difference between the other two groups (P 0.05). Conclusion the resistance to preloading fatigue stress of K3XF is better than that of K3XF.
【作者单位】： 首都医科大学口腔医学院牙体牙髓科;北京大学口腔医院第二门诊部;
【基金】：国家自然科学基金项目(编号:81200826)
【分类号】：R781.05
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本文编号：1955175