Evolutionary steps in the design and biofunctionalization of the additively manufactured sub-periosteal jaw implant 'AMSJI' for the maxilla.

The purpose of this prospective registry case-series study was to determine the biological, mechanical, and aesthetic improvements made to the additively manufactured sub-periosteal jaw implant (AMSJI) after timed installation. A total of nine patients received maxillary AMSJIs in three sessions over a 2-year period. Architectural changes, topological optimization, and amendments to biofunctionalization were performed after each phase through the use of computer-aided design, finite element analysis, and growing clinical experience. Biological improvements included sandblasting (large grit alumina) and acid-etching; increased hydrophilicity by plasma surface activation; deletion of the crestal connecting struts; relocation of the anterior post in front of the anterior part of the basal loop; protection of the Schneiderian membrane from fixation screw penetration; high polishing of the posts; major platform switch with equigingival connections; the use of removable posts that require local anaesthesia and do not inflict major biological damage; scaffolding for secondary stability; and the provision of an incision guide. Mechanical improvements included the creation of a generic design based on finite element analysis and the resulting topological optimization, a shortening of the wings, and a reduction in the number of fixation screws. Aesthetic improvements included relocation of the anterior post, as described above, and pink anodization of the posts.