IADR Abstract Archives
Differential Scanning Calorimetric Analysis of Different Commercially-Available Nickel-Titanium Endodontic Files
Objectives: Nickel-Titanium (NiTi) may exhibit superelastic or shape memory phenomena due to crystal phase changes between martensite and austenite. These phase transitions may be recorded using differential scanning calorimetry (DSC) with the most common reported parameter being the austenite-finish temperature (Af). Since the introduction of NiTi endodontic files in the late 1980s, a multitude of files have been commercialized. The purpose of this study was to observe the phase transitions within different commercially-available NiTi endodontic files.
Methods: Twenty-two as-received commercially-available NiTi endodontic file brands (n=6 files/brand) were examined by DSC. A 4-5mm segment from each file was sectioned 3mm from the tip using a low RPM, water-cooled diamond saw. Each file segment was weighed, placed in an aluminum crucible, and sealed. An empty aluminum crucible served as a reference during the DSC analysis. Specimens were analyzed over a temperature range from -100°C to 100°C, with a scan rate of 10°C/minute. Thermal peaks were evaluated with results analyzed via ANOVA (α= 0.05).
Results: Significant (p<0.05) differences were observed between brands. Overall, a wide range in endset/austenite-finish temperature is apparent among the files. Some discrepancy was found in the thermograms from the same brand indicating inconsistency in the fabrication process of these instruments.
Conclusions: The varied Af temperatures indicate different manufacturing variables are used. These phase transitions influence their mechanical properties and may affect the clinical performance of these NiTi endodontic files.
Methods: Twenty-two as-received commercially-available NiTi endodontic file brands (n=6 files/brand) were examined by DSC. A 4-5mm segment from each file was sectioned 3mm from the tip using a low RPM, water-cooled diamond saw. Each file segment was weighed, placed in an aluminum crucible, and sealed. An empty aluminum crucible served as a reference during the DSC analysis. Specimens were analyzed over a temperature range from -100°C to 100°C, with a scan rate of 10°C/minute. Thermal peaks were evaluated with results analyzed via ANOVA (α= 0.05).
Results: Significant (p<0.05) differences were observed between brands. Overall, a wide range in endset/austenite-finish temperature is apparent among the files. Some discrepancy was found in the thermograms from the same brand indicating inconsistency in the fabrication process of these instruments.
Conclusions: The varied Af temperatures indicate different manufacturing variables are used. These phase transitions influence their mechanical properties and may affect the clinical performance of these NiTi endodontic files.