Design, Metallurgical Features, and Mechanical Behaviour of NiTi Endodontic Instruments from Five Different Heat-Treated Rotary Systems

Jorge N R Martins; Emmanuel J N L Silva; Duarte Marques; Mário Rito Pereira; Victor T L Vieira; Sofia Arantes-Oliveira; Rui F Martins; Francisco Braz Fernandes; Marco Versiani

doi:10.3390/ma15031009

Design, Metallurgical Features, and Mechanical Behaviour of NiTi Endodontic Instruments from Five Different Heat-Treated Rotary Systems

Materials (Basel). 2022 Jan 28;15(3):1009. doi: 10.3390/ma15031009.

Authors

Jorge N R Martins^{1

2

3}, Emmanuel J N L Silva^{4

5}, Duarte Marques^{1

2

3

6}, Mário Rito Pereira¹, Victor T L Vieira⁴, Sofia Arantes-Oliveira^{1

6

7}, Rui F Martins⁸, Francisco Braz Fernandes⁹, Marco Versiani¹⁰

Affiliations

¹ Faculdade de Medicina Dentária, Universidade de Lisboa, 1600-277 Lisboa, Portugal.
² Grupo de Investigação em Bioquimica e Biologia Oral, Unidade de Investigação em Ciências Orais e Biomédicas (UICOB), 1600-277 Lisboa, Portugal.
³ Centro de Estudo de Medicina Dentária Baseada na Evidência (CEMDBE), 1600-277 Lisboa, Portugal.
⁴ Department of Endodontics, Grande Rio University (UNIGRANRIO), Rio de Janeiro 21210-623, Brazil.
⁵ Department of Endodontics, Fluminense Federal University, Niterio, Rio de Janeiro 24220-900, Brazil.
⁶ LIBPhys-FCT UID/FIS/04559/2013, 1600-277 Lisboa, Portugal.
⁷ BIOMAT, Laboratório de Biomateriais, Unidade de Investigação em Ciências Orais e Biomédicas (UICOB), 1600-277 Lisboa, Portugal.
⁸ UNIDEMI, Department of Mechanical and Industrial Engineering, NOVA School of Science and Technology, Universidade NOVA de Lisboa, 2829-516 Caparica, Portugal.
⁹ CENIMAT/I3N, Department of Materials Science, NOVA School of Science and Technology, Universidade NOVA de Lisboa, 2829-516 Caparica, Portugal.
¹⁰ Dental Specialty Center, Brazilian Military Police, Belo Horizonte 30350-190, Brazil.

Abstract

The current study aimed to compare the F1 endodontic instruments from five different heat-treated rotary systems regarding their design, metallurgical properties, and mechanical performance. Five F1 root canal shaping instruments (ProTaper Gold [PTG], Premium Taper Gold, Go-Taper Flex, EdgeTaper Platinum, and Super Files Blue)-plus, a conventional ProTaper Universal (PTU)-which were evaluated regarding their design, nickel/titanium ratio, phase transformation temperatures, microhardness, cyclic fatigue, and torsional and bending strengths. Mood's median test was used for the statistical comparison with a significance set at 5%. The instruments were similar regarding the nickel/titanium ratio and overall design. Go-Taper Flex had the closest transformation temperatures to PTG. PTU and Go-Taper Flex had the highest microhardness (408.3 and 410.5 HVN). The time to fracture of Super Files Blue was three and seven times higher than PTG and PTU, respectively. No difference was observed in the maximum torque to fracture among PTG (1.30 N·cm) and the other systems, except for the Premium Taper Gold (1.05 N·cm) and Go-Taper Flex (1.10 N·cm). Significantly lower bending loads than PTG (269.2 gf) were observed for the EdgeTaper Platinum (158.3 gf) and Premium Taper Gold (103.5 gf) instruments. Super Files Blue outperformed PTG in the cyclic fatigue test, while EdgeTaper Platinum and Premium Taper Gold were more flexible. Premium Taper Gold and Go-Taper Flex showed lower torsional strength.

Keywords: bending load; cyclic fatigue; endodontics; microhardness; rotary system; torsional resistance.