The Digital Renaissance of Customized Subperiosteal Implants—Clinical Outcomes, Surgical Workflow, and Current Evidence for the Rehabilitation of Severely Atrophic Jaws: A Narrative Review

Background/Objectives: Rehabilitation of the severely atrophic edentulous jaw remains one of the most demanding challenges in oral and maxillofacial reconstruction, particularly when extensive bone augmentation is contraindicated, has previously failed, or is refused by the patient. Subperiosteal implants, first introduced in the 1940s and largely abandoned due to poor long-term performance, have re-emerged over the past decade as a viable alternative through the integration of cone-beam computed tomography (CBCT)-based virtual planning, computer-aided design/computer-aided manufacturing (CAD/CAM), and additive manufacturing. This review summarizes current evidence on the clinical outcomes, surgical workflow, and indications of customized, digitally designed subperiosteal implants. Materials and Methods: A structured literature search was performed in PubMed and Scopus, supplemented by manual searching, to identify publications relevant to the predefined clinical and conceptual scope of this narrative review. Search terms addressed subperiosteal implants, digital/CAD-CAM workflows, additive manufacturing, severe jaw atrophy, and clinical outcomes. Predefined selection criteria were applied to maintain consistency with the scope of the review, and the literature-selection process was documented using a descriptive flow diagram. Results: Sixty-two publications were retained as the core literature informing the narrative synthesis, comprising systematic reviews and meta-analyses, retrospective and multicenter clinical studies, case series, case reports, and biomechanical/technical investigations. The synthesized evidence indicates short-to-medium-term implant survival generally exceeding 90%, with soft-tissue exposure and dehiscence as the most frequently reported complications, and a decline in survival on longer follow-up. Digitally designed subperiosteal implants are increasingly reported for severely resorbed maxillae and mandibles, oncologic and post-traumatic defects, syndromic patients, and cases of failed conventional or zygomatic implant therapy. Conclusions: Digital workflows have renewed clinical interest in subperiosteal implants by enabling patient-specific design and digitally supported planning and manufacturing. However, the evidence base remains dominated by case reports and heterogeneous retrospective series, underscoring the need for prospective, standardized, long-term studies.