Titanium is the most widely used material in the field of oral implantology, thanks to its excellent mechanical properties and its biocompatibility.
Titanium, however, is an extremely reactive metal and, in contact with atmospheric oxygen, rapidly forms (nanoseconds), on its surface, a thin layer of oxide (passivation). At high temperatures, in the presence of oxygen, the oxidation of the metal is greatly increased, together with the risk of formation of brittle carbides and nitrides. The high reactivity of titanium has long hindered the welding of this material. A possible solution, to be able to effectively weld titanium, is to protect its surface with the use of inert gases (to avoid oxidation) and work in clean conditions (to avoid contamination). The gas flow, however, must be optimized so as not to cause the onset of porosity in the junction area. It is then necessary to adequately clean the surfaces from any organic residue (grease, oil, contact contamination), a requirement, in this case, easily present on the implant material.
Among the different welding technologies, the resistance one is well applied to titanium, given its high electrical resistivity (40 10-8  m), for manufactured products with a maximum thickness of 1.5-2mm. This technology, which sees the two surfaces to be spliced ​​in contact and under load both before the heating, both during heating and cooling, allows, in itself, to considerably reduce the internal oxidation of the joint. During heating, the material can reach full melting or only a temperature high enough to allow the formation of a solid state junction.