More Than Anchors: Evidence for Screw-Mediated Osseointegration in Customised Subperiosteal Implants for Severe...

To describe the digital planning, fabrication and clinical outcome of a customised subperiosteal implant used to rehabilitate a severely atrophic edentulous maxilla, and to propose a comparative, quantitative framework for evaluating the bone-titanium contact surface generated by the screw-fixation system, in support of the hypothesis that these screws contribute a genuine osseointegrative component to implant stability, beyond their acknowledged mechanical role.

We report the case of a 63-year-old female patient with total maxillary edentulism and severe bone atrophy, treated with a digitally designed, CAD/CAM-manufactured titanium subperiosteal implant anchored by 27 osteosynthesis screws (2 mm diameter, 7 mm length). The cumulative bone-titanium contact surface generated by the fixation screws was compared, using the formula S = π × d × h, with that of a conventional restoration supported by eight endosseous implants (4 mm × 8 mm).

The comparative analysis showed a larger cumulative contact surface for the screw-fixation system (≈1068.7 mm²) than for the endosseous alternative (≈804.2 mm²). Clinical and radiological stability was maintained beyond one year of follow-up, without signs of implant mobility or peri-implant inflammation.

The findings of the present study support the hypothesis that osteoinductive and osseointegrative processes contribute meaningfully to the long-term success of modern subperiosteal implants, in addition to the mechanical retention provided by the fixation screws.