Implants Placed with the All-On-4 Technique: A Radiographic Retrospective Study on 156 Implants with a 5- to 14-Year Follow-up.

ABSTRACT

The aim of this retrospective study was to evaluate the performance of implants placed with the All-on-4 technique after a mean time in function of 9 years. A total of 34 patients with 156 implants were selected for this study 18 patients underwent tooth extraction on the day of implant placement (Group D), and 16 patients were already edentulous (Group E). A periapical radiograph was taken at a mean follow-up of 9 years (range 5 to 14 years). Success and survival rates and the prevalence of peri-implantitis were calculated. Statistical analysis was used to assess comparisons between groups. After a mean follow-up of 9 years, the cumulative survival rate was 97.4% and the success rate was 77.4%. The difference between the initial and final radiographs resulted in a mean marginal bone loss (MBL) of 1.3 ± 1.06 mm (range 0.1 to 5.3 mm). No differences were seen between Groups D and E. Peri-implantitis affected 15 implants (9.6%) in 9 patients (26.5%). This study shows that the All-on-4 technique is a reliable treatment method for both edentulous patients and patients requiring tooth extractions, with results maintained over a long follow-up period. The present MBL results are similar to those around implants in other rehabilitation types.