Four-mm-short implants in the rehabilitation of posterior atrophic jaws: A retrospective study on 212 patients with a mean follow-up of 8.02 years

Objective: This study aimed to assess clinical efficacy of 4-mm-short implants in patients with posterior severe vertical bone atrophy in the medium- and long-term follow-up. Materials and Methods: Patients rehabilitated with 4-mm-short implants in the posterior atrophic jaws, with a minimum follow-up of 3 years post-loading, were included in the study. Data were collected for eligible patients, and marginal bone loss (MBL) for each implant was evaluated. The research outcomes were implant failure, MBL and complications. Results: A total of 212 patients with 496 implants were included, resulting in a mean follow-up of 8.02 ± 2.17 years. The implant survival rate was 95.36% (95% CI: 93.12%–97.04%). More implant failures were observed in the maxilla (p =.02) and fewer failures were observed in patients undergoing more number of hygienic sessions per year (p <.001). The average MBL after 1-year-loading was 0.47 mm, increasing to 0.59 mm after 10 years; after 3 years no statistically significant increase in MBL was observed. Maxillary implants showed greater bone loss than mandibular ones (p <.001). More frequent professional oral hygiene sessions per year resulted being related with reduced MBL (p <.001). Conclusions: Four-mm-short implants showed high survival rates with an up to 10-year follow-up. Their use can offer a fixed prosthetic solution for patients with posterior vertical bone atrophy, minimizing surgical invasiveness, rehabilitative times and costs.