, Volume 107, Issue 4, pp 473–481 | Cite as

Evaluation of the usage-induced degradation of Genius and Reciproc nickel–titanium reciprocating instruments

  • Luigi GeneraliEmail author
  • Alessia Borghi
  • Luca Lusvarghi
  • Giovanni Bolelli
  • Paolo Veronesi
  • Andrea Vecchi
  • Ugo Consolo
  • Carlo Becce
  • Carlo Bertoldi
  • Paolo Sassatelli
Original Article


The aim of this study was to characterize the main features and the usage-induced degradation of the Genius file after four severely curved root canal instrumentations and to compare their properties to the Reciproc files. Brand new and ex vivo used files were analysed by scanning electron microscopy (SEM) with energy-dispersive X-ray spectrometry (EDS), differential scanning calorimetry (DSC), X-ray diffraction (XRD), optical metallography, and nano-indentation to disclose their morphological, chemical, mechanical, thermal, and phase composition features. Nano-indentation data were statistically analysed using the Student’s t test for normal distribution or the Kolmogorov–Smirnov test for not-normal distributions. SEM analysis showed the presence of micro-cracks near the tip on both files after ex vivo usage test. EDS analysis confirmed that both files are manufactured from an almost equiatomic NiTi alloy. DSC analysis revealed that the transition temperature of the Genius is below 20 °C, while that of the Reciproc is above 20 °C. XRD analysis of Genius files identified cubic B2 austenite with minor peaks of residual monoclinic B19 martensite, while the contemporaneous presence of martensite, austenite and hexagonal R-phase was observed in the Reciproc files. Significant differences in nanohardness and modulus of elasticity (P < .05) were observed in both Genius and Reciproc files before and after use. The collected results showed that both instruments can be safely used as single-use files.


Differential scanning calorimetry Genius files Metallurgical characterization Reciproc Reciprocating motion 



The authors would like to thank Professor Francesco Cavani for assistance in statistical analysis.

Compliance with ethical standards

Conflict of interest

The authors declare that they have no conflict of interest.


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Copyright information

© The Society of The Nippon Dental University 2019

Authors and Affiliations

  • Luigi Generali
    • 1
    Email author
  • Alessia Borghi
    • 1
  • Luca Lusvarghi
    • 2
  • Giovanni Bolelli
    • 2
  • Paolo Veronesi
    • 2
  • Andrea Vecchi
    • 3
  • Ugo Consolo
    • 1
  • Carlo Becce
    • 4
  • Carlo Bertoldi
    • 1
  • Paolo Sassatelli
    • 2
  1. 1.Department of Surgery, Medicine, Dentistry and Morphological Sciences with Transplant Surgery, Oncology and Regenerative Medicine Relevance (CHIMOMO)University of Modena and Reggio EmiliaModenaItaly
  2. 2.Department of Engineering Enzo Ferrari (DIEF)University of Modena and Reggio EmiliaModenaItaly
  3. 3.NCS-LabModenaItaly
  4. 4.Private PracticeSavonaItaly

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