Jorge N R Martins1, Emmanuel João Nogueira Leal Silva2, Duarte Marques3, António Ginjeira4, Francisco Manuel Braz Fernandes5, Gustavo De Deus6, Marco Aurélio Versiani7. 1. Unidade de Investigação em Ciências Orais e Biomédicas, Faculdade de Medicina Dentária, Universidade de Lisboa, Lisboa, Portugal; Centro de Estudo de Medicina Dentária Baseada na Evidência, Faculdade de Medicina Dentária, Universidade de Lisboa, Lisboa, Portugal; Instituto de Implantologia, Lisboa, Portugal. Electronic address: jnr_martins@yahoo.com.br. 2. Department of Endodontics, School of Dentistry, Grande Rio University, Rio de Janeiro, Rio de Janeiro, Brazil; Department of Endodontics, Fluminense Federal University, Niteroi, Rio de Janeiro, Brazil. 3. Centro de Estudo de Medicina Dentária Baseada na Evidência, Faculdade de Medicina Dentária, Universidade de Lisboa, Lisboa, Portugal; Instituto de Implantologia, Lisboa, Portugal; LIBPhys-FCT UID/FIS/04559/2013, Lisboa, Portugal. 4. Department of Endodontics, Faculdade de Medicina Dentária, Universidade de Lisboa, Lisboa, Portugal. 5. CENIMAT/I3N, Department of Materials Science, NOVA School of Science and Technology, Universidade NOVA de Lisboa, Caparica, Portugal. 6. Department of Endodontics, Fluminense Federal University, Niteroi, Rio de Janeiro, Brazil. 7. Dental Specialty Center, Brazilian Military Police, Minas Gerais, Brazil.
Abstract
INTRODUCTION: The aim of this study was to evaluate the cyclic fatigue resistance of 3 replicalike rotary instruments compared with their original brand systems using continuous rotation and optimum torque reverse (OTR) kinematics. METHODS: New F1 rotary instruments (n = 20 per group) from ProTaper Universal (Dentsply Maillefer, Ballaigues, Switzerland) and ProTaper Gold (Dentsply Maillefer) original brand systems were compared with 3 replicalike instruments (U-File [Dentmark, Ludhiana, India], Super Files [Shenzhen Flydent Medical, Shenzhen, China], and Super Files Blue [Shenzhen Flydent Medical]) regarding cyclic fatigue resistance. In each group, the selected instruments were randomly distributed into 2 subgroups (n = 10) according to the kinematics. In the rotary group (ROT), the instruments were activated with a continuous clockwise rotation (300 rpm, 1.5 Ncm), whereas in the OTR group, asymmetric oscillatory motion was performed setting the OTR function at 300 rpm and adjusting the torque limit at the minimum level using the TriAuto ZX2 motor (J Morita, Kyoto, Japan). The time to fracture was recorded and statistically compared according to the kinematics (ROT × OTR) and the instrument type (replicalike × original brand) using the independent sample t test (α = 0.05). Additionally, the metal alloy characterization of each system was performed by differential scanning calorimetry and energy-dispersive X-ray spectroscopy. RESULTS: Statistical analysis revealed significantly higher time to fracture for all rotary systems tested in OTR motion compared with continuous rotation (P < .05) with a mean percentage increase ranging from 52.1% (ProTaper Gold) to 156.7% (U-File). The replicalike instruments showed a significantly higher time to fracture compared with the respective original brand instruments in either ROT or OTR motion (P < .05). Replicas presented austenitic temperatures above the ones displayed by the original brands and an almost equiatomic ratio between nickel and titanium elements. CONCLUSIONS: OTR motion significantly improved the fatigue resistance of both original and replicalike systems. The replicas showed higher cyclic fatigue resistance than original brand instruments and higher transition temperatures to the austenitic phase.
INTRODUCTION: The aim of this study was to evaluate the cyclic fatigue resistance of 3 replicalike rotary instruments compared with their original brand systems using continuous rotation and optimum torque reverse (OTR) kinematics. METHODS: New F1 rotary instruments (n = 20 per group) from ProTaper Universal (Dentsply Maillefer, Ballaigues, Switzerland) and ProTaper Gold (Dentsply Maillefer) original brand systems were compared with 3 replicalike instruments (U-File [Dentmark, Ludhiana, India], Super Files [Shenzhen Flydent Medical, Shenzhen, China], and Super Files Blue [Shenzhen Flydent Medical]) regarding cyclic fatigue resistance. In each group, the selected instruments were randomly distributed into 2 subgroups (n = 10) according to the kinematics. In the rotary group (ROT), the instruments were activated with a continuous clockwise rotation (300 rpm, 1.5 Ncm), whereas in the OTR group, asymmetric oscillatory motion was performed setting the OTR function at 300 rpm and adjusting the torque limit at the minimum level using the TriAuto ZX2 motor (J Morita, Kyoto, Japan). The time to fracture was recorded and statistically compared according to the kinematics (ROT × OTR) and the instrument type (replicalike × original brand) using the independent sample t test (α = 0.05). Additionally, the metal alloy characterization of each system was performed by differential scanning calorimetry and energy-dispersive X-ray spectroscopy. RESULTS: Statistical analysis revealed significantly higher time to fracture for all rotary systems tested in OTR motion compared with continuous rotation (P < .05) with a mean percentage increase ranging from 52.1% (ProTaper Gold) to 156.7% (U-File). The replicalike instruments showed a significantly higher time to fracture compared with the respective original brand instruments in either ROT or OTR motion (P < .05). Replicas presented austenitic temperatures above the ones displayed by the original brands and an almost equiatomic ratio between nickel and titanium elements. CONCLUSIONS: OTR motion significantly improved the fatigue resistance of both original and replicalike systems. The replicas showed higher cyclic fatigue resistance than original brand instruments and higher transition temperatures to the austenitic phase.
Authors: Vicente Faus-Matoses; Raúl Pérez García; Vicente Faus-Llácer; Ignacio Faus-Matoses; Óscar Alonso Ezpeleta; Alberto Albaladejo Martínez; Álvaro Zubizarreta-Macho Journal: Int J Environ Res Public Health Date: 2022-04-06 Impact factor: 3.390
Authors: Jorge N R Martins; Duarte Marques; Isabel Vasconcelos; Sofia Arantes-Oliveira; João Caramês; Francisco Manuel Braz Fernandes Journal: Dent J (Basel) Date: 2022-02-17
Authors: Javier Nino-Barrera; Jose Sanchez-Aleman; Manuel Acosta-Humanez; Luis Gamboa-Martinez; Carlos Cortes-Rodriguez Journal: Sci Rep Date: 2021-06-21 Impact factor: 4.379