Role of the Flat-Designed Surface in Improving the Cyclic Fatigue Resistance of Endodontic NiTi Rotary Instruments

Gianluca Gambarini; Gabriele Miccoli; Marco Seracchiani; Tatyana Khrenova; Orlando Donfrancesco; Maurilio D’Angelo; Massimo Galli; Dario Di Nardo; Luca Testarelli

doi:10.3390/ma12162523

Materials (Aug 2019)

Role of the Flat-Designed Surface in Improving the Cyclic Fatigue Resistance of Endodontic NiTi Rotary Instruments

Gianluca Gambarini,
Gabriele Miccoli,
Marco Seracchiani,
Tatyana Khrenova,
Orlando Donfrancesco,
Maurilio D’Angelo,
Massimo Galli,
Dario Di Nardo,
Luca Testarelli

Affiliations

Gianluca Gambarini: Department of Oral and Maxillo-Facial Sciences, Sapienza University of Rome, 00161 Rome, Italy
Gabriele Miccoli: Department of Oral and Maxillo-Facial Sciences, Sapienza University of Rome, 00161 Rome, Italy
Marco Seracchiani: Department of Oral and Maxillo-Facial Sciences, Sapienza University of Rome, 00161 Rome, Italy
Tatyana Khrenova: Department of Oral and Maxillo-Facial Sciences, Sapienza University of Rome, 00161 Rome, Italy
Orlando Donfrancesco: Department of Oral and Maxillo-Facial Sciences, Sapienza University of Rome, 00161 Rome, Italy
Maurilio D’Angelo: Department of Oral and Maxillo-Facial Sciences, Sapienza University of Rome, 00161 Rome, Italy
Massimo Galli: Department of Oral and Maxillo-Facial Sciences, Sapienza University of Rome, 00161 Rome, Italy
Dario Di Nardo: Department of Oral and Maxillo-Facial Sciences, Sapienza University of Rome, 00161 Rome, Italy
Luca Testarelli: Department of Oral and Maxillo-Facial Sciences, Sapienza University of Rome, 00161 Rome, Italy

DOI: https://doi.org/10.3390/ma12162523
Journal volume & issue: Vol. 12, no. 16
p. 2523

Abstract

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The aim of this study was to investigate the role of the flat-designed surface in improving the resistance to cyclic fatigue by comparing heat-treated F-One (Fanta Dental, Shanghai, China) nickel−titanium (NiTi) rotary instruments and similar prototypes, differing only by the absence of the flat side. The null hypothesis was that there were no differences between the two tested instruments in terms of cyclic fatigue lifespan. A total of 40 new NiTi instruments (20 F-One and 20 prototypes) were tested in the present study. The instruments were rotated with the same speed (500 rpm) and torque (2 N) using an endodontic motor (Elements Motor, Kerr, Orange, CA, USA) in the same stainless steel, artificial canal (90° angle of curvature and 5 mm radius). A Wilcoxon−Mann−Whitney test was performed to assess the differences in terms of time to fracture and the length of the fractured segment between the flat- and non-flat-sided instruments. Significance was set at p = 0.05. The differences in terms of time to fracture between non-flat and flat were statistically significant (p < 0.001). In addition, the differences in terms of fractured segment length were statistically significant (p = 0.034). The results of this study highlight the importance of flat-sided design in increasing the cyclic fatigue lifespan of NiTi rotary instruments.

Published in Materials

ISSN: 1996-1944 (Online)
Publisher: MDPI AG
Country of publisher: Switzerland
LCC subjects: Technology: Electrical engineering. Electronics. Nuclear engineering; Technology: Engineering (General). Civil engineering (General); Science: Natural history (General): Microscopy; Science: Physics: Descriptive and experimental mechanics
Website: http://www.mdpi.com/journal/materials/

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