Defects in nickel-titanium instruments after clinical use. Part 1: Relationship between observed imperfections and factors leading to such defects in a cohort study.

Abstract

The purpose of this study was to examine three different types of nickel-titanium (NiTi) systems (ProTaper [Dentsply Maillefer, Ballaigues, Switzerland], ProTaper for Hand Use [Dentsply Maillefer], and K3 [SybronEndo, Orange, CA]) that were discarded by 3 endodontic clinics. The instruments were evaluated for defects and factors leading to instrument deformation or fracture. A total of 1682 instruments were collected over 16 months and were examined. The location of the defect, if any, was recorded. The overall prevalence of unwinding defects was 3% and fracture 5%; the rates differed significantly between clinics. For one brand (ProTaper) used at two different clinics, a defect rate (fracture and distortion combined) of 7% (clinic A) vs. 13% (clinic B) for Shaping files (P < 0.05), and about 4% vs. 10% for Finishing files (P < 0.05) was observed. Fragments of broken Shaping file were significantly longer in clinic A than for clinic B (P < 0.05). The lowest defect rate was found for K3 instruments: unwinding 1%, and fracture 3%. It was concluded that the defect rates of NiTi instruments were influenced by such factors as the operator, preparation technique and instrument design.

DOI: 10.1016/j.joen.2008.10.014

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@article{Shen2009DefectsIN, title={Defects in nickel-titanium instruments after clinical use. Part 1: Relationship between observed imperfections and factors leading to such defects in a cohort study.}, author={Ya Jing Shen and Markus P P Haapasalo and Gary Shun-pan Cheung and Bin Peng}, journal={Journal of endodontics}, year={2009}, volume={35 1}, pages={129-32} }