[高压灭菌器对R相旋转器械表面微观结构及循环疲劳抗力的影响]

[Effect of autoclave on surface microstructure and cyclic fatigue resistance of R-phase rotary instruments].

作者信息

Yang Y J, Hou B X, Hou X M

机构信息

Department of Endodontics, Capital Medical University School of Stomatology, Beijing 100050, China.

Second Clinical Division, Peking University School and Hospital of Stomatology & National Clinical Research Center for Oral Diseases & National Engineering Laboratory for Digital and Material Technology of Stomatology & Beijing Key Laboratory of Digital Stomatology, Beijing 100101, China.

出版信息

Beijing Da Xue Xue Bao Yi Xue Ban. 2018 Oct 18;50(5):882-886.

PMID:30337752

Abstract

OBJECTIVE

To compare the effects of autoclave on surface microstructure and cyclic fatigue resistance of K3XF and K3.

METHODS

Forty-eight size 25, 0.06 taper 25 mm-long K3XF or K3 were randomly divided into 4 groups (n=12). The instruments from group 1 were not autoclaved, and the groups 2 to 4 underwent autoclave for 10 cycles, 20 cycles, and 30 cycles, respectively. The surface microstructure of two instruments randomly selected from each group was observed using scanning electron microscope (SEM). The remaining 10 instruments were submitted to the cyclic fatigue test by using a simulated metal root canal with curvature of 60° and radius 3.5 mm. The time till fracture was recorded, the number of cyclic fatigue (NCF) calculated, the fragment length evaluated, and the topographic features were analyzed using SEM. The data were analyzed using the two-way ANOVA analysis by SAS 9.3 software at a significance level of P<0.05.

RESULTS

SEM observation identified rough features on the surface of K3XF with micropores existing evenly. K3 was characterized by machining grooves, which located specifically in the flute, leaving a smooth cutting edge. After autoclave, SEM observation indicated that the micropores in the surface of K3XF became larger and more, whereas the machining grooves in the surface of K3 were squeezed, out of shape and flaking. As far as the NCF was concerned, new K3XF was 210±59, and no significant difference was found after 10, 20, and 30 cycles of autoclave for K3XF, values being 178±37, 208±48, and 227±43, respectively (P>0.05). For K3, the new one was 145±38, and no significant difference in NCF was demonstrated after 10 and 20 cycles of autoclave, with the values of 128±43 and 124±46, respectively (P>0.05). However, after 30 cycles of autoclave of K3, significant increase to 216±38 was identified (P<0.05). Topographic features demonstrated typical cyclic fatigue for all the groups.

CONCLUSION

The surface roughness of K3XF was increased after autoclave, while the cyclic resistance remained stable after up to 30 cycles.

摘要

目的

比较高压蒸汽灭菌对K3XF和K3器械表面微观结构及循环疲劳抗力的影响。

方法

将48支尺寸为25、锥度0.06、长度25mm的K3XF或K3器械随机分为4组（每组n = 12）。第1组器械不进行高压蒸汽灭菌，第2至4组分别进行10次、20次和30次高压蒸汽灭菌循环。使用扫描电子显微镜（SEM）观察从每组中随机选取的2支器械的表面微观结构。其余10支器械通过使用曲率为60°、半径为3.5mm的模拟金属根管进行循环疲劳测试。记录直至断裂的时间，计算循环疲劳次数（NCF），评估碎片长度，并使用SEM分析形貌特征。使用SAS 9.3软件进行双向方差分析，显著性水平为P<0.05。

结果

SEM观察发现K3XF表面有粗糙特征，微孔均匀分布。K3的特征是加工槽，具体位于凹槽中，切削刃光滑。高压蒸汽灭菌后，SEM观察表明K3XF表面的微孔变得更大、更多，而K3表面的加工槽被挤压、变形和剥落。就NCF而言，新的K3XF为210±59，K3XF经过10次、20次和30次高压蒸汽灭菌循环后未发现显著差异，其值分别为178±37、208±48和227±43（P>0.05）。对于K3，新器械为145±38，K3经过10次和20次高压蒸汽灭菌循环后，NCF无显著差异，其值分别为128±43和124±46（P>0.05）。然而，K3经过30次高压蒸汽灭菌循环后，显著增加至216±38（P<0.05）。形貌特征显示所有组均出现典型的循环疲劳。