title: Surface topography, hardness, and frictional properties of GFRP for esthetic orthodontic wires.
abstract: In our previous study, glass-fiber-reinforced plastics (GFRPs) made from polycarbonate and glass fiber for esthetic orthodontic wires were prepared by using pultrusion. The purpose of the present study was to investigate the surface topography, hardness, and frictional properties of GFRPs. To investigate how fiber diameter affects surface properties, GFRP round wires with a diameter of 0.45 mm (0.018 in.) were prepared incorporating either 13 μm (GFRP-13) or 7 μm (GFRP-7) glass fibers. As controls, stainless steel (SS), cobalt-chromium-nickel alloy, β-titanium (β-Ti) alloy, and nickel-titanium (Ni-Ti) alloy were also evaluated. Under scanning electron microscopy and scanning probe microscopy, the β-Ti samples exhibited greater surface roughness than the other metallic wires and the GFRP wires. The dynamic hardness and elastic modulus of GFRP wires obtained by the dynamic micro-indentation method were much lower than those of metallic wires (p < 0.05). Frictional forces against the polymeric composite brackets of GFRP-13 and GFRP-7 were 3.45 ± 0.49 and 3.60 ± 0.38 N, respectively; frictional forces against the ceramic brackets of GFRP-13 and GFRP-7 were 3.39 ± 0.58 and 3.87 ± 0.48 N, respectively. For both bracket types, frictional forces of GFRP wires and Ni-Ti wire were nearly half as low as those of SS, Co-Cr, and β-Ti wires. In conclusion, there was no significant difference in surface properties between GFRP-13 and GFRP-7; presumably because both share the same polycarbonate matrix. We expect that GFRP wires will deliver superior sliding mechanics with low frictional resistance between the wire and bracket during orthodontic treatment.
authors: Department of Orthodontics, Nihon University School of Dentistry at Matsudo, 2-870-1 Sakaecho Nishi, Matsudo, Chiba, 271-8587, Japan.
authors: Toshihiro
authors: T
authors: Inami
authors: Department of Dental Biomaterials, Nihon University School of Dentistry at Matsudo, 2-870-1 Sakaecho Nishi, Matsudo, Chiba, 271-8587, Japan.
authors: Yasuhiro
authors: Y
authors: Tanimoto
authors: Department of Orthodontics, Nihon University School of Dentistry at Matsudo, 2-870-1 Sakaecho Nishi, Matsudo, Chiba, 271-8587, Japan.
authors: Masaru
authors: M
authors: Yamaguchi
authors: Department of Conservative Dentistry, Division of Biomaterials and Engineering, Showa University School of Dentistry, 1-5-8 Hatanodai, Shinagawa-ku, Tokyo, 142-8555, Japan.
authors: Yo
authors: Y
authors: Shibata
authors: Department of Dental Biomaterials, Nihon University School of Dentistry at Matsudo, 2-870-1 Sakaecho Nishi, Matsudo, Chiba, 271-8587, Japan.
authors: Norihiro
authors: N
authors: Nishiyama
authors: Department of Orthodontics, Nihon University School of Dentistry at Matsudo, 2-870-1 Sakaecho Nishi, Matsudo, Chiba, 271-8587, Japan.
authors: Kazutaka
authors: K
authors: Kasai
mesh_terms: D017276:Friction; D005898:Glass / Q000737:chemistry*; D006244:Hardness; D006801:Humans; D009969:Orthodontic Wires
chemical_list: C009753:fiberglass
keywords: biomechanics; fiber-reinforced composite; mechanical properties; orthodontic; surface characterization