Background <p>Custom-made subperiosteal dental implants (CMSDIs) have shown potential as a reconstructive solution for rehabilitating maxillary defects following post-COVID-19 rhino-orbital mucormycosis (PCROM). This systematic review evaluates the clinical outcomes of CMSDIs in such defects.</p> Materials and Methods <p>A systematic search was conducted across PubMed, Google Scholar, Semantic Scholar, and the Cochrane Library for studies published through March 2025. Data regarding patient demographics, implant materials, design techniques, surgical approaches, prosthetic rehabilitation, and postoperative complications were extracted. A descriptive analysis of the included studies was performed.</p> Results <p>A total of seven studies (two case series and five case reports) were published between 2022 and 2024, involving 46 patients (aged 30–67 years). All studies were from India. The software used for planning and designing included Mimics^®(<i>n</i> = 2), Exocad(<i>n</i> = 1), and Geomagic(<i>n</i> = 1). Titanium implants were used, milled(<i>N</i> = 1), and 3D printed(<i>N</i> = 6). CMSDI placement was performed between 6 and 12 months post-surgery in 93.47% (43/46). Abutments were cement retained(<i>n</i> = 41) and screw-retained(<i>n</i> = 5). Rehabilitation was performed immediately(<i>n</i> = 20), &lt; 1 month(<i>n</i> = 2), 1 to 4 months(<i>n</i> = 22), and after 4 months(<i>n</i> = 1). The overall complication rate was 26.08%(12/46), and complications were prosthetic-related (66.66%,8/12), surgical (25%, <i>n</i> = 3), and implant-related (8.33%, <i>n</i> = 1). Follow-up duration ranged from three to 12 months.</p> Conclusion <p>CMSDIs demonstrate potential as a reconstructive option for PCROM defects, with a complication rate of 26.08%, predominantly prosthetic-related. However, the evidence remains preliminary, derived exclusively from case reports and case series with short follow-up and restricted to Indian populations, limiting generalizability. Well-designed multi-center prospective trials are urgently required to validate long-term effectiveness and comparative advantages of CMSDIs.</p> Trial Registration <p>Prospero No: CRD420251022490.</p>