Early Laser-Welded Titanium Frameworks Supported by Implants in the Edentulous Mandible: A 15-Year Comparative Follow-Up Study

Background: Comparative long-term knowledge of different framework materials in the edentulous implant patient is not available for 15 years of follow-up. Purpose: To report and compare a 15-year retrospective data on implant-supported prostheses in the edentulous mandible provided with laser-welded titanium frameworks (test) and gold alloy frameworks (control). Materials and Methods: Altogether, 155 patients were consecutively treated with abutment-level prostheses with two early generations of fixed laser-welded titanium frameworks (titanium group). Fifty-three selected patients with gold alloy castings formed the control group. Clinical and radiographic 15-year data were collected and compared for the groups. Results: All patients who were followed up for 15 years (n = 72) still had a fixed prosthesis in the mandible at the termination of the study. The 15-year original prosthesis cumulative survival rate (CSR) was 89.2 and 100% for titanium and control frameworks (p = .057), respectively (overall CSR 91.7%). The overall 15-year implant CSR was 98.7%. The average 15-year bone loss was 0.59 mm (SD 0.56) and 0.98 mm (SD 0.64) for the test and control groups (p = .027), respectively. Few (1.3%) implants had > 3.1-mm accumulated bone loss after 15 years. The most common complications for titanium frameworks were resin or veneer fractures and soft tissue inflammation. Fractures of the titanium metal frame were observed in 15.5% of the patients. More patients had framework fractures in the earliest titanium group (Ti-1 group) compared to the gold alloy group (p = .034). Loose and fractured implant screw components were few (2.4%). Conclusion: Predictable overall long-term results could be maintained with the present treatment modality. Fractures of the metal frames and remade prostheses were more common in the test group, and the gold alloy frameworks had a tendency to work better when compared with welded titanium frameworks during 15 years. However, on the average, more bone loss was observed for implants supporting gold alloy frameworks.