Comparative Clinical Outcomes of Two Different Zygomatic Implant Protocols for the Rehabilitation of Severely Atrophic Maxillae: A Retrospective Analysis

This retrospective study aimed to compare extended sinus elevation and extramaxillary surgical protocols for restoring severely atrophic maxillae with zygomatic implants (ZIs) and evaluate their clinical effectiveness. The study included patients who were treated at a dental clinic in Italy from 2012 to 2022 who received fixed screw-retained complete dentures supported by either two or four ZIs. The patients underwent a minimum 1-year follow-up after loading, following two protocols: the hybrid and the quad protocol. Digital planning incorporated CBCT scans, intraoral scans, and digital prosthetic plans within implant-planning software. Surgical techniques involved extended sinus elevation and extramaxillary techniques, using the ZAGA approach for ZI placement. The results showed that out of 19 patients with a mean age of 65.3 years, a total of 56 ZIs and 20 standard implants were used, with no failures observed in either the implants or the definitive prostheses, resulting in a 100% survival rate. According to the ORIS criteria, overall success was achieved in terms of implant stability, sinus health, peri-implant soft tissue condition, and prosthetic function. Only two ZIs (3.6%) exhibited minor gingival recession and moderate thread exposure, which were closely monitored through professional hygiene maintenance. Both the extended sinus elevation and extramaxillary protocols demonstrated comparable clinical outcomes and minimal complications in the restoration of severely atrophic maxillae with ZIs. However, further extensive studies involving larger, multicenter designs and longer follow-up periods are needed to validate and refine these outcomes.