Mechanical and frictional properties of aesthetic orthodontic wires obtained by hard chrome carbide plating

Abstract

Background/purpose Although aesthetic wire coating has been increasing in demand, it has problems that changes in mechanical properties and increase in frictional force. The aim of this study was to evaluate the coating of the wire, as characterized by aesthetics, in terms of low and constant friction and mechanical properties. Materials and methods Hard chrome carbide-plated (HCCP) wires (HCCP group), commercially available polymer-coated wires (P group), rhodium-coated wires (R group), and uncoated wires (control group) were used. For all wire types, a stainless steel wire of dimensions 0.017 inch × 0.025 inch was used. They were evaluated by three-point bending, friction testing, surface observation, and colorimetric testing. Results The HCCP group was not significantly different from the control group in terms of flexural strength ( σ ) and flexural modulus ( E ) ( σ : p = 0.90, E : p = 0.35). However, it was significantly inferior compared to the three other groups in terms of the maximum static and kinetic frictional forces under both dry and wet conditions ( p < 0.05). In the surface observation, scratches were observed on the wire after the friction test. In the colorimetric test, no significant difference was observed between the HCCP group and the R group ( p > 0.05). Conclusion The mechanical properties of the HCCP wire were not significantly different compared to the control group. The frictional force of the HCCP wire was significantly lower than the other group. Therefore, the HCCP wire was suggested to increase the efficiency of tooth movement in clinics.

A Comparison of the Compositional, Microstructural, and Mechanical Characteristics of Ni-Free and Conventional Stainless Steel Orthodontic Wires

“…All the wires showed the presence of surface cracks and pores, a finding which is in accordance with previous reports [16,17,18]. It is well known that orthodontic wires undergo extensive cold working and the orientation of cracks and pores parallel to the long axis of wires should be appended to this manufacturing process [19].…”

Evaluating the Mechanical Properties of Zinc-Coated Stainless Steel Orthodontic Wires Using Physical Vapor Deposition

“…Furthermore, the 0.019 × 0.025 SS orthodontic wires are used in the “space closure stage” in which wires are preserved in the mouth for a long time. Even though a few studies had used SS wires for their coating procedure [ 15 , 16 , 18 , 21 – 23 ], others used NiTi wires to improve the wire's mechanical properties [ 11 ]. However, it does not seem to be logical to use NiTi wires due to high costs and side effects, if kept in the mouth for a long time.…”

Surface Reformation of Medical Devices with DLC Coating

“…A black coating is applied to medical devices used in tests and treatments to prevent the reflection of surgical light [ 6 ]. However, depending on the cleaning and usage environment, the coating material may peel off and subsequently become unable to prevent the reflection of surgical light.…”

“…Therefore, current intracorporeal medical devices, such as speculums, need to be coated with a matte black coating, such as black chrome plating, that suppresses light reflection [ 4 ]. However, metal materials, such as black chrome plating, have a high coefficient of friction on the contact surface with the living body, causing discomfort and pain stemming from the friction experienced by the patient [ 6 ]. In addition, depending on the part of the biologic organ into which a device is inserted, the metal material may elute because of acid in the body, thereby causing problems like the deterioration of the black chrome plating and skin inflammation in patients with metal allergies [ 7 ].…”