Dipartimento di Scienze Odontostomatologiche, Sapienza Università di Roma, Rome, Italy.
Ann Ist Super Sanita. 2010;46(4):400-4. doi: 10.4415/ANN_10_04_07.
The goal of the study is to evaluate if the use of rotary nickel-titanium (RNT) instruments, as Hedstroem files, is safe. Twelve twisted files (TF) RNT instruments size 06-25 were selected and randomly divided in 2 groups of 6 instruments each. Group A (new instruments) were used as control. Group B (test) instruments were clinically used only as Hedstroem files in a canal that had been previously instrumented to the working length with other 06-25 RNT instruments. Group B instruments were used only in the straight portion of the canal (1 minute at 1000 rpm). A cyclic fatigue test was performed for each instrument of groups. Data were statistically analyzed (Student's t-test). Results showed no significant difference (P > 0.05) between groups A and B. Data confirmed that the use of TF instruments as Hedstroem files is a safe procedure. Cross section images and volumes of the same instrument, before and after cyclic fatigue testing, have been obtained by means of microtomographic analysis to evaluate possible microstructure alterations.
本研究的目的是评估是否可以安全使用旋转镍钛器械（RNT），如 Hedstroem 锉。选择了 12 个扭转镍钛锉（TF）RNT 器械 06-25 号，并随机分为两组，每组 6 个器械。组 A（新器械）作为对照组。组 B（测试）器械仅作为 Hedstroem 锉在先前使用其他 06-25 RNT 器械达到工作长度的根管中使用。组 B 器械仅用于根管的直段（1000rpm 下 1 分钟）。对每组的每个器械进行了循环疲劳试验。对数据进行了统计学分析（Student's t 检验）。结果显示组 A 和 B 之间无显著差异（P > 0.05）。数据证实，将 TF 器械用作 Hedstroem 锉是一种安全的操作。通过微断层分析获得了同一器械在循环疲劳试验前后的横截面图像和体积，以评估可能的微观结构变化。
