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A Journal on Dentistry and Maxillofacial Surgery

Official Journal of the Italian Society of Odontostomatology and Maxillofacial Surgery
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Minerva Stomatologica 2008 September;57(9):393-8


language: English, Italian

Bending properties of nickel-titanium instruments: a comparative study

Gambarini G. 1, Pongione G. 1, Rizzo F. 1, Testarelli L. 1, Cavalleri G. 2, Gerosa R. 2

1 Department of Dental Sciences La Sapienza University, Rome, Italy 2 Department of Dental Sciences University of Verona, Verona, Italy


Aim. The aim of the present study was to evaluate the bending properties of twisted file instruments, and compare them with other commercially available nickel-titanium (NiTi) instruments (Mtwo and Hero) manufactured with traditional methods.
Methods. Despite NiTi superelastic properties, flexibility of NiTi instruments is limited by size and taper. A new manufacturing process involving twisting of a ground blank combined with heat treatment has been developed by SybronEndo, aiming to produce a NiTI rotary file with superior flexibility: the Twisted File (TF). Experimental procedures strictly followed the testing methodology described in ISO 3630-1. Bending moment was measured when the instrument attained a 45° bend. Data were collected and statistically analyzed.
Results. Results showed that TF were the most flexibile instruments, with a significant improvement in flexibility (P< 0.05). ranging from 100% to 250% over the other tested instruments. Even if flexibility is also influenced by instruments design, such a great improvement is mainly related to the new TF manufacturing process.
Conclusion. The flexibility is influenced by instruments design, such a great improvement is mainly related to the new manufacturing process developed by SybronEndo, which seems to play a major role in increasing the flexibility of TF instruments.

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