IADR Abstract Archives
Bending and Phase Transformation Comparison of ProTaper Endodontic Files
Objectives: ProTaper Gold endodontic files are advertised as ProTaper Universal files with “advanced metallurgy” brought about by a proprietary heat treatment step. The objective of this study was to compare the bending moment and phase transformation behavior of these two endodontic files of the same design but different in manufacturing processes.
Methods: ProTaper Universal and ProTaper Gold (Dentsply Sirona, size F4) nickel-titanium (NiTi) endodontic files were evaluated for bending and phase transformation behavior using a torsiometer and Differential Scanning Calorimeter (DSC), respectively. Following ISO 3630, the bending moment to induce a 45 degree bend was measured for each file (n=8/product). Phase transformation behavior during heating/cooling was examined between -80 and 100C using DSC (n=4/product) with a scan rate of 10C/min. Bending moment and austenite finish (Af) temperature were compared with a t-test.
Results: ProTaper Universal (95±15 gm*cm) was significantly (p<0.0001) stiffer than ProTaper Gold (61±7 gm*cm). With respect to phase transformation behavior, ProTaper Universal possessed an austenite finish temperature of 14.8±1.3C, whereas ProTaper Gold’s Af temperature was significantly (p<0.0001) greater at 48.0±0.4C. ProTaper Universal would be expected to be fully austenite whereas ProTaper Gold would be more martensitic at oral temperatures.
Conclusions: ProTaper Gold is more flexible than ProTaper Universal due to a heat treatment step that raises the austenite finish temperature and produces a NiTi file of different phase composition.
Methods: ProTaper Universal and ProTaper Gold (Dentsply Sirona, size F4) nickel-titanium (NiTi) endodontic files were evaluated for bending and phase transformation behavior using a torsiometer and Differential Scanning Calorimeter (DSC), respectively. Following ISO 3630, the bending moment to induce a 45 degree bend was measured for each file (n=8/product). Phase transformation behavior during heating/cooling was examined between -80 and 100C using DSC (n=4/product) with a scan rate of 10C/min. Bending moment and austenite finish (Af) temperature were compared with a t-test.
Results: ProTaper Universal (95±15 gm*cm) was significantly (p<0.0001) stiffer than ProTaper Gold (61±7 gm*cm). With respect to phase transformation behavior, ProTaper Universal possessed an austenite finish temperature of 14.8±1.3C, whereas ProTaper Gold’s Af temperature was significantly (p<0.0001) greater at 48.0±0.4C. ProTaper Universal would be expected to be fully austenite whereas ProTaper Gold would be more martensitic at oral temperatures.
Conclusions: ProTaper Gold is more flexible than ProTaper Universal due to a heat treatment step that raises the austenite finish temperature and produces a NiTi file of different phase composition.