Realizzazione di protesi immediate di lunga durata nei pazienti con atrofia ossea del mascellare superiore tramite saldatura intra-orale a resistenza elettrica.

The electric resistance welding approach can be used to create an immediate metal-reinforced provisional prosthesis in cases of severe maxillary resection of soft and hard tissues and in severely atrophic cases. The aim of the research was to determine whether the prosthesis made using the electric resistance approach could be improved as to achieve the status of final restorations. The research campaign comprised of the following in-vitro studies: a microstructural characterization and hardness properties of electric resistance welding titanium joints, a fatigue test of titanium-bar joints made with the laser and the electric resistance welding techniques, a pull-out retention test of conical welding caps and a cytotoxicity test of the titanium joints made using the electric resistance welding technique. Within its limitations, this study campaign demonstrated the following: 1)the electric resistance welding did not induce appreciable modifications in the geometry of the abutments; 2)the temperature increase was only limited to few hundreds of microns from the joint, while it was negligible in the rest of the material, 3)the heat generated during welding process caused no detachment of any molten metal drop; 4)the joint made using the electric resistance welding technique was able to withstand fatigue forces are equal or superior to the standard values used as reference, ranging between 120 N and 140 N for 5*106 cycles; 5)the welding caps provide a reliable connection between the abutment and a fixed prosthesis without the use of any cement; 6)the welding procedure did not jeopardize the biocompatibility of commercially pure grade 2. The prosthesis made using the electric resistance welding approach, despite the intrinsic difference with titanium milled or gold-alloy fused restorations, could be planned as a final restoration in a patient affected by severe atrophy of the maxilla. A clinical study is needed to confirm this statement.