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Cyclic fatigue of ProFile rotary instruments after prolonged clinical use
Author(s) -
Gambarini G.
Publication year - 2001
Publication title -
international endodontic journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.988
H-Index - 119
eISSN - 1365-2591
pISSN - 0143-2885
DOI - 10.1046/j.1365-2591.2001.00259.x
Subject(s) - cyclic stress , fracture (geology) , materials science , fatigue testing , instrumentation (computer programming) , breakage , crown (dentistry) , orthodontics , dentistry , medicine , computer science , composite material , operating system
Aim The purpose of the present study was to evaluate resistance to cyclic fatigue of new and used ProFile Ni–Ti rotary instruments. Methodology Used instruments were operated in 10 clinical cases using passive instrumentation and a crown‐down preparation technique. Cyclic fatigue testing of new and used engine‐driven instruments was then performed with a specific device which allowed the instruments to rotate freely inside a stainless steel artificial canal, whilst maintaining conditions close to the clinical situation. Instruments were rotated until fracture occurred and time to fracture was visually recorded with a chronometer. Results A significant reduction of rotation time to breakage (life span) was noted between new and used instruments. In all sizes new instruments were significantly more resistant than used ones (two‐sample t ‐test, P < 0.01). No instrument underwent intracanal failure during clinical use. Conclusions Prolonged clinical use of Ni–Ti engine‐driven instruments significantly reduced their cyclic fatigue resistance. Nevertheless, each rotary instrument was successfully operated in up to 10 clinical cases without any intracanal failure.