Influence after Clinical Use and Sterilization onroFile Nickel-Titanium Rotary Instruments
Date Issued
2008
Date
2008
Author(s)
Liou, Ji-Uei
Abstract
A major concern with use of nickel-titanium engine-driven rotary instruments is fracture without warning. The purpose of this study was to analyze the type and frequency of defects in ProFile nickel-titanium rotary endodontic files after routine clinical use and to draw conclusions regarding the reasons for failure. The differential scanning calorimetric (DSC) studies were utilized to undergo phase transformation within rotary nickel-titanium (Ni-Ti) endodontic instruments of the as-received condition and after more heat sterilization cycles. Static Bending Test was tested on the mechanical behavior and cyclic fatigue devices were tested on fatigue resistance of rotary endodontic Ni–Ti instruments after more heat sterilization cycles. The result was nickel-titanium rotary endodontic files after routine clinical used had more percentage on fracture (58.4%) than distortion (41.6%). The large size file had more percentage on fracture than distortion. Fracture of endodontic rotary instruments could occur under two circumstances: torsional fracture and cyclic fatigue. The cyclic fatigue (58.6%) was the major type than torsional fracture (41.4%). The differential scanning calorimetric (DSC) studies exhibit the total enthalpy change decrease within rotary nickel-titanium (Ni-Ti) endodontic instruments after 11 heat sterilization cycles. The heat cycle of the hybrid Ni–Ti instruments may be effective to increase the flexibility and decrease on cyclic fatigue cycle, specially with dry heat sterilization than steam autoclave and cassette autoclave.
Subjects
rotary endodontic Ni–Ti instruments
heat sterilization
differential scanning calorimetric (DSC)
bending test
cyclic fatigue
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