Department of Operative Dentistry and Endodontics, Faculty of Odonto-Stomatology, University of Medicine and Pharmacy at Ho Chi Minh City, Ho Chi Minh City, 700000, Vietnam.
BMC Oral Health. 2021 Oct 2;21(1):488. doi: 10.1186/s12903-021-01857-w.
The transformation temperatures were important values, influencing the mechanical properties and clinical performance of nickel-titanium instruments. The aim of this study was to determine the transformation temperatures of three rotary nickel-titanium (NiTi) instruments: Reciproc, HyFlex CM Pro, and Neoniti before and after simulated clinical uses.
Ninety new NiTi instruments of three single-file instruments: Reciproc, HyFlex CM Pro, and Neoniti were divided into three groups. Thirty instruments of each group were divided into 3 subgroups (10 instruments for each subgroup): new, one-time simulated clinical used and sterilised, and three times simulated clinical used and sterilized subgroups. The instruments were in the as-received condition for the new subgroups, one time used in the plastic endo-training blocks and sterilised for the one-time subgroups, and three times used in the plastic endo-training blocks and sterilised for the three times subgroups. Each instrument in subgroups was cut into four small segments of 4-5 mm. All segments of instruments were analysed using Differential Scanning Calorimetry (DSC). Data was collected and analysed using SPSS version 20.0 with ANOVA test or Kruskal-Wallis test at the significant level of 0.05.
There was not significant difference between before and after simulated clinical use with sterilised procedure in three NiTi instrument systems. The austenite-finish (A) temperatures of three instrument systems were higher than that of the human body (37 °C), of these, the A temperature of Neoniti was highest and that of HyFlex CM Pro was lowest.
The austenite-finish (A) temperatures of three NiTi instruments were higher than that of human body temperature, therefore, material was in the phase transformation from martensite to austenite, gives the instruments more flexibility when used in the clinical situation.
相变温度是重要的数值，影响镍钛器械的机械性能和临床性能。本研究的目的是确定三种旋转镍钛（NiTi）器械（Reciproc、HyFlex CM Pro 和 Neoniti）在模拟临床使用前后的相变温度。
90 个新的镍钛器械分为三个单文件器械：Reciproc、HyFlex CM Pro 和 Neoniti。每组 30 个器械分为 3 个亚组（每组 10 个）：新的、一次性模拟临床使用和消毒的、以及三次模拟临床使用和消毒的亚组。新亚组的器械处于原始状态，一次性亚组在塑料根管训练块中使用一次并消毒，三次亚组在塑料根管训练块中使用三次并消毒。每个亚组的器械被切割成 4-5mm 的四个小段。所有器械的小段均使用差示扫描量热法（DSC）进行分析。使用 SPSS 版本 20.0 收集和分析数据，采用方差分析或 Kruskal-Wallis 检验，显著性水平为 0.05。
在三种 NiTi 器械系统中，经过模拟临床使用和消毒程序后，没有显著差异。三种器械系统的奥氏体开始（A）温度均高于人体（37°C），其中 Neoniti 的 A 温度最高，HyFlex CM Pro 的 A 温度最低。
三种镍钛器械的奥氏体开始（A）温度高于人体温度，因此，在临床使用时，材料处于从马氏体向奥氏体转变的阶段，赋予器械更大的柔韧性。
