Selective use of dynamic navigation for anatomically challenging immediate loading of all-on-four implants: a retrospective cohort study.

Abstract

Purpose: Edentulism compromises oral function and quality of life. The All-on-4 concept offers a fixed alternative to conventional dentures under immediate loading. However, evidence on outcomes in anatomically challenging arches, particularly with dynamic navigation, remains limited. This study reports early clinical and radiographic outcomes, and the feasibility, of immediate-loading all-on-4 in a real-world setting using an anatomy-driven allocation strategy with freehand and navigation workflows.

Materials and methods: This retrospective cohort included consecutive patients treated between November 2023 and February 2025. Dynamic navigation was selectively applied in unfavorable arches; freehand surgery was used otherwise. Four implants per arch supported screw-retained provisional prostheses delivered within 24-36 hours. Primary outcomes were implant and arch-level survival and marginal bone level (MBL) change. Secondary outcomes included complications and provisional prosthesis survival.

Results: Twenty-two patients (23 arches; 92 implants) were analyzed: 13 arches freehand and 10 navigation. Median follow-up was 5.11 months. Five implants failed (5.43%), all in the maxilla, affecting four arches (one navigation, three freehand). Implant survival was 94.23% (freehand) and 95.00% (navigation). MBL change was negligible, consistent with early remodeling and measurement variability. Biological complications occurred in 8 implants (8.70%), and two provisional fractures were repaired; 22 of 23 prostheses remained functional (95.65%).

Conclusion: Immediate-loading All-on-4 with selective navigation achieved high short-term implant and prosthesis survival and minimal MBL variation. These findings support the feasibility of navigation in demanding arches in routine practice, warranting confirmation in prospective studies with longer follow-up.