Inclusion Criteria:  patients (>18 years old) who had undergone prosthetic rehabilitation using one or more dental implants, with at least 1 year of follow-up after loading, and patients who had returned for a maintenance appointment at the Ville Turro Dental Clinic of Vita-Salute San Raffaele University in Milan patients under antiretroviral therapy (ART) at the same hospital.  Exclusion Criteria:  Patients who discontinued antiretroviral therapy patients not undergoing therapy patients with uncontrolled systemic diseases (diabetes [HbA1c>7]) patients under treatment with any medications that may have an effect on bone turnover and mucosal healing (steroids, bisphosphonate therapy ) Pregnancy or breastfeeding women patients who discontinued the oral maintenance (more than 1 appointment)