Niobium is a rare, soft, malleable, ductile, gray-white metal. Niobium is used in alloys including stainless steel. It improves the strength of the alloys, particularly at low temperatures. Alloys containing niobium are used in jet engines and rockets, beams and girders for buildings and oil rigs, and oil and gas pipelines. This element also has superconducting properties. It is used in superconducting magnets for particle accelerators, MRI scanners and NMR equipment. Niobium oxide compounds are added to glass to increase the refractive index, which allows corrective glasses to be made with thinner lenses. Niobium pentoxide may be used as a novel filler for dental adhesive resin. Superelastic titanium alloys (titanium-niobium-zirconium and titanium-niobium-tantalum) are considered to be the more advantageous choice for dental implants than titanium alloys due to their physico-mechanical properties close to those of the bone tissue. Niobium is an inert material so it might be beneficial in lowering the rate of restenosis, when used in coronary stents. Niobium and its compounds may be toxic (niobium dust causes eye and skin irritation) , but there are no reports of human being poisoned by it. Apart from measuring its concentration, no research on niobium in humans has been undertaken.