Thursday, July 24, 2008

Fatigue resistance of engine-driven rotary nickel-titanium instruments produced by new manufacturing methods.

J Endod. 2008 Aug;34(8):1003-5. Epub 2008 Jun 25.

Fatigue resistance of engine-driven rotary nickel-titanium instruments produced by new manufacturing methods.

Gambarini G, Grande NM, Plotino G, Somma F, Garala M, De Luca M, Testarelli L.

La Sapienza University, Rome, Italy. ggambarini@tin.it

The aim of the present study was to investigate whether cyclic fatigue resistance is increased for nickel-titanium instruments manufactured by using new processes. This was evaluated by comparing instruments produced by using the twisted method (TF; SybronEndo, Orange, CA) and those using the M-wire alloy (GTX; Dentsply Tulsa-Dental Specialties, Tulsa, OK) with instruments produced by a traditional NiTi grinding process (K3, SybronEndo). Tests were performed with a specific cyclic fatigue device that evaluated cycles to failure of rotary instruments inside curved artificial canals. Results indicated that size 06-25 TF instruments showed a significant increase (p < 0.05) in the mean number of cycles to failure when compared with size 06-25 K3 files. Size 06-20 K3 instruments showed no significant increase (p > 0.05) in the mean number of cycles to failure when compared with size 06-20 GT series X instruments. The new manufacturing process produced nickel-titanium rotary files (TF) significantly more resistant to fatigue than instruments produced with the traditional NiTi grinding process. Instruments produced with M-wire (GTX) were not found to be more resistant to fatigue than instruments produced with the traditional NiTi grinding process.

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