The 'All-on-four' protocol in HIV-positive patients: A prospective, longitudinal 7-year clinical study.

PURPOSE This prospective study aims to evaluate the clinical outcomes of 'All-on-four' rehabilitations in controlled human immunodeficiency virus (HIV)-positive patients. MATERIALS AND METHODS Edentulous patients requiring an implant prosthetic restoration of one or both jaws were enrolled in the present study. Each patient received at least one fixed full-arch prosthesis. Four implants, immediately loaded, were placed in each jaw using the 'All-on-four' protocol. Marginal bone loss, implant and prosthetic failure, biological and mechanical complications, and serological levels (CD4 cell count, CD4/CD8 ratio, and HIV viral load) were recorded up to 7-year follow-up. RESULTS A total of 116 implants were placed in 24 patients, and 29 rehabilitations based on the 'All-on-four' concept were achieved. Implant failures were registered in four patients (10 of 116 implants), and the implant survival rate was 91.37%. At the 7-year radiographic evaluation, peri-implant crestal bone loss averaged 1.91 ± 1.3 mm for upright maxillary implants (n = 30 implants) and 1.79 ± 1.28 mm for tilted maxillary implants (n = 30 implants). In the mandible, mean peri-implant crestal bone loss was 1.54 ± 1.27 mm for upright implants (n = 28) and 1.5 ± 1.3 mm for tilted implants (n = 28). No statistically significant correlation was found between serological parameters and marginal bone levels at 6 months, or through 7 years of annual follow-up (P > 0.05). A statistically significant linear correlation (P < 0.001) was found between early implant failure and HIV viral load. The CD4/CD8 ratio was significantly correlated with late implant failure (P = 0.009). CONCLUSIONS Within the limitations of this prospective 7-year longitudinal study, HIV-positive patients with a stable immune system can be candidates for the 'All-on-four' treatment concept.