INTRAORALLY ELECTRICALLY WELDED VERSUS CAST METAL FRAMEWORKS FOR SCREW-RETAINED IMPLANT-SUPPORTED MAXILLARY PROSTHESES: ONE-YEAR POST-LOADING DATA FROM A SPLITMOUTH RANDOMIZED CONTROLLED TRIAL

PURPOSE. To compare the clinical outcomes of electrically welded versus cast frameworks for screw-retained implant-supported maxillary prostheses.

MATERIALS AND METHODS. Twelve patients with edentulous maxillae received six implants each. After four months of unloaded healing, shaping abutments were connected to the implants on one randomly selected side, and titanium wire was bent and attached to the implants by intraoral electric welding (EWF). A cast metal framework (CMF) was constructed on the other side. The fit between the implant abutments and their respective prosthetic abutments was assessed at the framework try-in stage. Then, both cast and welded frameworks were picked up in the complete maxillary denture after modification. Patients were followed up to one year after loading. Outcome measures were: prosthesis and implant failures, complications, peri-implant bone loss, and passive prothesis fit.

RESULTS. No patient dropped out and no prosthesis or implant failed. CMF was associated with a higher rate of complications (P = 0.16); RD: -0.25; 95% CI: -0.60 to 0.10) than EWF, but the difference was not statistically significant. One year after loading, the CMF group had lost an average of 0.97±0.15 mm of peri-implant bone vs. 0.43±0.28 mm in the EWF group. This difference was statistically significant (mean difference = -0.54 mm, 95%CI -1.03, -0.31, P = 0.005). All 12 EWF prostheses were passive, while eight CMF (67.3%) prostheses were passive, and 4 were not (33.3%). The difference was statistically significant (P = 0.02; risk difference -0.33, CI 95% -0.05 to -0.61).

CONCLUSIONS. Electrically welded implant-supported framework could be a superior treatment option compared to conventional cast framework as it seems to be associated with less peri-implant bone loss and better passive prosthesis fit.