Dayanne Lopes da Silva1, Emanuel Santos2, Sérgio de Souza Camargo3, Antônio Carlos de Oliveira Ruellas4. 1. a PhD student, Department of Orthodontics, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil. 2. b Postdoctoral Researcher, Metallurgical and Materials Engineering Program, COPPE (Alberto Luiz Coimbra Institute - Graduate School and Research in Engineering), Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil. Professor, Civil Engineering Program, Centro Universitário de Volta Redonda (UNIFOA), Volta Redonda, Brazil. 3. c Professor, Metallurgical and Materials Engineering Program, COPPE (Alberto Luiz Coimbra Institute - Graduate School and Research in Engineering), Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil. 4. d Professor, Department of Orthodontics, Universidade Federal do Rio de Janeiro, CNPQ Researcher (National Council for Scientific and Technological Development), Rio de Janeiro, Brazil.
Abstract
OBJECTIVE: To evaluate the material composition, mechanical properties (hardness and elastic modulus), and scratch resistance of the coating of four commercialized esthetic orthodontic archwires. MATERIALS AND METHODS: The coating composition of esthetic archwires was assessed by Fourier-transform infrared spectroscopy (FTIR). Coating hardness and elastic modulus were analyzed with instrumented nano-indentation tests. Scratch resistance of coatings was evaluated by scratch test. Coating micromorphologic characteristics after scratch tests were observed in a scanning electron microscope. Statistical differences were investigated using analysis of variance and Tukey post hoc test. RESULTS: The FTIR results indicate that all analyzed coatings were markedly characterized by the benzene peak at about 1500 cm(-1). The coating hardness and elastic modulus average values ranged from 0.17 to 0.23 GPa and from 5.0 to 7.6 GPa, respectively. Scratch test showed a high coating elasticity after load removal with elastic recoveries >60%, but different failure features could be observed along the scratches. CONCLUSION: The coatings of esthetic archwires evaluated are probably a composite of polyester and polytetrafluoroethylene. Delamination, crack propagation, and debris generation could be observed along the coating scratches and could influence its durability in the oral environment.
OBJECTIVE: To evaluate the material composition, mechanical properties (hardness and elastic modulus), and scratch resistance of the coating of four commercialized esthetic orthodontic archwires. MATERIALS AND METHODS: The coating composition of esthetic archwires was assessed by Fourier-transform infrared spectroscopy (FTIR). Coating hardness and elastic modulus were analyzed with instrumented nano-indentation tests. Scratch resistance of coatings was evaluated by scratch test. Coating micromorphologic characteristics after scratch tests were observed in a scanning electron microscope. Statistical differences were investigated using analysis of variance and Tukey post hoc test. RESULTS: The FTIR results indicate that all analyzed coatings were markedly characterized by the benzene peak at about 1500 cm(-1). The coating hardness and elastic modulus average values ranged from 0.17 to 0.23 GPa and from 5.0 to 7.6 GPa, respectively. Scratch test showed a high coating elasticity after load removal with elastic recoveries >60%, but different failure features could be observed along the scratches. CONCLUSION: The coatings of esthetic archwires evaluated are probably a composite of polyester and polytetrafluoroethylene. Delamination, crack propagation, and debris generation could be observed along the coating scratches and could influence its durability in the oral environment.