Dental Implants in Adults With Intellectual Disabilities: A Multicenter Retrospective Study. Part 2: Prosthesis Outcomes.

BACKGROUND: Adults with intellectual disabilities often experience tooth loss and face barriers to accessing implant-supported rehabilitation. OBJECTIVE: To evaluate implant-supported prosthesis outcomes in adults with non-syndromic intellectual disabilities and to identify variables associated with prosthetic success. METHODS: A total of 247 implant-supported prostheses placed in 137 patients from 7 dental centers in Spain, France, Italy, and South Korea were analysed. Patient characteristics, oral health, implant features, and prosthesis-related variables were collected. Prosthetic outcomes were categorized as "undamaged and successful", "damaged but successful", "loss", or "undamaged but unsuccessful". Success was assessed using an adapted United States Public Health Service (USPHS) clinical rating system. RESULTS: At a mean follow-up of 68.1 months, 94.3% of prostheses were considered successful. Cumulative survival rates were 97% at 5 years, 88% at 10 years, and 85% at 15 years. The most common technical complications were screw loosening (10.4%) and chipping (10%). Fixed prostheses predominated (92.3%), with 65.3% crowns and 34.6% bridges. Screw retention was most common (84.2%), and 94.3% followed a conventional loading protocol. General anaesthesia was used in nearly half of the cases during the impression step, although most framework and delivery procedures were performed without sedation. Among the multinomial mixed-effects models, implant design was significantly associated with the outcome category "damaged but successful", whereas age at first implant surgery was significantly associated with the outcome category "loss" (OR = 0.93 per additional year; 95% CI: 0.87-0.99; p = 0.031). However, the model showed no overall discriminatory ability (AUC-ROC = 0.500), and these associations should therefore be considered exploratory rather than clinically predictive. Random-effects binomial models showed improved discrimination (AUC-ROC = 0.754), although no statistically significant associations were identified. CONCLUSION: Implant-supported prosthetic rehabilitation is a viable and successful long-term treatment option for adults with non-syndromic intellectual disabilities, achieving outcomes comparable to those in the general population.