Long-term clinical outcomes of All-on-4 immediate implant rehabilitation: a 10-year retrospective study

Background Immediate fixed full-arch rehabilitation using the All-on-4 concept is widely used for edentulous patients, but evidence integrating long-term implant, prosthetic, biological, and patient-reported outcomes beyond 5 years remains limited. This study evaluated long-term clinical outcomes of All-on-4 immediate rehabilitation over a maximum follow-up period of 10 years. Methods This single-center retrospective secondary analysis included 16 edentulous patients treated between September 2009 and September 2015, with 76 original implants supporting 19 full-arch fixed prostheses. Longitudinal assessments included marginal bone loss (MBL), modified plaque index (mPI), and modified sulcus bleeding index (mSBI). Three implants that failed during early healing were replaced and excluded from primary longitudinal analyses; sensitivity analyses were performed including replacement implants. Implant and prosthetic survival were evaluated using predefined criteria. Patient-reported outcomes, including Oral Health Impact Profile-14 (OHIP-14) and satisfaction, were assessed during postoperative follow-up. Results Three implants failed during early healing in one patient, resulting in an implant-level Kaplan–Meier survival estimate of 96.05% (95% CI, 88.26%–98.71%). All 19 treated arches remained functionally rehabilitated through the last follow-up or censoring. Two definitive prostheses required complete replacement because of ceramic chipping, and five screw-loosening episodes occurred in two patients. At 10 years, cumulative MBL was 1.79 ± 0.21 mm around vertical anterior implants and 1.85 ± 0.27 mm around tilted posterior implants, with no significant difference after adjustment. Both mPI and mSBI increased over time, indicating increased plaque accumulation and peri-implant soft-tissue inflammation during long-term maintenance, whereas implant configuration had no significant effect in the primary analyses. At 10 years, peri-implant mucositis was retrospectively classified in 37 of 57 assessed implants (64.9%) and 7 of 12 assessed patients (58.3%); no peri-implantitis was identified in available records. Conclusions Within the limitations of this small, selected, retrospective cohort, All-on-4 full-arch rehabilitation showed high long-term implant and prosthesis survival, with longitudinal marginal bone and peri-implant clinical outcomes documented over up to 10 years. Prosthetic maintenance and replacement were required during follow-up. At the patient-reported assessment, overall satisfaction with the treatment outcomes was favorable.