Long-term clinical results of additively manufactured subperiosteal implants for the treatment of the severely atrophic maxilla.

This study constitutes a retrospective analysis, with the objective of evaluating the long-term clinical outcomes of custom-made DMLS maxillary subperiosteal implants in patients diagnosed with severe bone atrophy over a follow-up period of up to 10 years. A total of ten patients with severe maxillary bone loss, classified as Cawood and Howell Class IV to VI, who were unsuitable for conventional dental implant treatment, were treated with subperiosteal implants between 2015 and 2025. The implants were designed on the basis of computed tomography (CT) imaging data using CAD/CAM software and then manufactured via a direct metal laser sintering (DMLS) process. Post-operative evaluation included radiological imaging and clinical assessment of implant stability, complications, and survival rates. A total of 10 implants were placed, of which eight remained functional and stable during the follow-up period, while two had to be removed due to inadequate fit and recurrent infection. Radiological follow-up confirmed stable bone levels with minimal signs of resorption in all successful cases. Early complications, such as swelling and discomfort, resolved without compromising function, and late complications were rare, observed in only two cases. All implants placed in 2015 were intact and fully functional at the 10-year mark. A Kaplan-Meier survival analysis demonstrated a 10-year survival probability of 80%. In these severely atrophic cases, a limited number of fixation screws (7-10) were used, selectively placed in areas of sufficient bone thickness identified through CT-guided virtual planning. This individualized approach minimized surgical invasiveness and allowed procedures to be performed under local anesthesia in an outpatient setting. Due to the reduced number of fixation points and the compromised anatomical conditions, prosthetic loading was intentionally delayed by approximately five months to ensure secure osseointegration and long-term implant stability. Custom-designed DMLS titanium alloy subperiosteal implants demonstrate excellent long-term results in the treatment of severely atrophic maxillae, offering a reliable alternative to traditional bone augmentation techniques. While the results demonstrate the potential of these implants and their long-term use, further research with larger cohorts and longer follow-up is recommended to optimize their clinical application.