Do Mechanical and Physicochemical Properties of Orthodontic NiTi Wires Remain Stable In Vivo?

Abstract

Introduction and Aim. Exceptional properties of the NiTi archwires may be jeopardized by the oral cavity; thus its long-term effect on the mechanical and physiochemical properties of NiTi archwires was the aim of work. Material and Methods. Study group comprised sixty 0.016 × 0.022 NiTi archwires from the same manufacturer evaluated (group A) after the first 12 weeks of orthodontic treatment. 30 mm long pieces cut off from each wire prior to insertion formed the control group B. Obeying the strict rules of randomization, all samples were subjected to microscopic evaluation and nanoindentation test. Results. Both groups displayed substantial presence of nonmetallic inclusions. Heterogeneity of the structure and its alteration after usage were found in groups B and A, respectively. Conclusions. Long-term, reliable prediction of biomechanics of NiTi wires in vivo is impossible, especially new archwires from the same vendor display different physiochemical properties. Moreover, manufacturers have to decrease contamination in the production process in order to minimize risk of mutual negative influence of nickel-titanium archwires and oral environment.

Influence of intraoral application of antiseptics and fluorides during orthodontic treatment on corrosion and mechanical characteristics of nickel-titanium alloy in orthodontic appliances

“…Similar findings were reported earlier. 18 It was also possible that corrosion and friction lead to the dissolving/breaking of the tips of the bumps on the wire, which made it less rugged. Other authors 19 reported higher homogeneity for the as-received archwires, while there were heterogeneous surfaces with craters and bumps after clinical use.…”

Corrosion Behavior and In Vitro Cytotoxicity of Ni–Ti and Stainless Steel Arch Wires Exposed to Lysozyme, Ovalbumin, and Bovine Serum Albumin

“…The potential adverse reactions caused by toxic ions restrict the application of metallic materials in the human body. 24 From another perspective, materials prepared with specific proteins would have numerous applications in biomedicine. However, it remains unclear how surface chemistry and topography affect protein adsorption.…”

“…Nickel is considered the main toxic element in Ni–Ti and SS, and nickel leached from alloys into surrounding tissues could inhibit cell proliferation and differentiation by changing the expression of related genes. The potential adverse reactions caused by toxic ions restrict the application of metallic materials in the human body . From another perspective, materials prepared with specific proteins would have numerous applications in biomedicine.…”

Load-Deflection and Friction Properties of PEEK Wires as Alternative Orthodontic Wires

“…For example, conventional metal orthodontic wire and brackets have been demonstrated to release nickel and chromium ions [ 20 , 21 ], and metal brackets couples with metal wires such as stainless steel or nickel-titanium (Ni-Ti) undergo galvanic reaction and corrosion in artificial saliva or in fluoride mouthwash [ 22 ]. Moreover, it has been reported that there is a substantial presence of nonmetallic inclusions, mainly in the form of silicates and oxides on the surface of Ni-Ti wires [ 23 ]. It has also been claimed that nonmetallic impurities already present at the postproductive stage and increased under influence of the oral environment must not be neglected.…”