Laser welding of titanium in dentistry.

Unalloyed titanium of the quality used for osseointegrated implants by the method of Brånemark is also sometimes used for the metallic part of the prosthetic superstructure placed on the fixtures and for crowns and bridges of conventional type. Forty bars of titanium, 8 of ASTM B 348 grade-1 quality and 32 of ASTM B 348 grade-2 quality, were laser-welded, using dissimilar laser joint variables. Tensile strength, 0.2% proof stress, and percentage elongation of the welded bars were measured and compared with the corresponding values for the titanium bars as delivered and with those of brazed type-3 gold alloy bars of similar dimensions. The type of fracture was evaluated from fractographs. The results showed that the use of certain defined laser joint variables during welding produced values for the mechanical properties studied which were more favorable than those obtained from the brazed gold bars. The fracture of the titanium specimens was ductile, with dimples occurring at the fracture surfaces.