Complications and Patient-Centered Outcomes of an Implant- Supported Single Crown After Immediate and Delayed Loading: A Systematic Review and Meta-analysis

Purpose: To assess the complications, satisfaction, and quality of life of patients rehabilitated with delayed and immediate loading of single crowns. Materials and Methods: An electronic search was conducted in PubMed/MEDLINE, Scopus, Web of Science, Cochrane Library, and Embase databases up to February 2023. Only prospective studies and randomized and nonrandomized clinical trials comparing immediate and delayed loading were included. For the quantitative analysis, dichotomous and consistent variables were evaluated with a 95% confidence interval. Results: A total of 20 studies were evaluated. No statistically significant difference was observed between protocols: satisfaction (I²: 0%; P = .42), quality of life (I²: 0 %; P = .05), biologic complications (I²: 9%; P = .17), mechanical complications (I²: 58%; P = .84), and survival rate (I²: 0%; P = .38). The subgroup analysis showed significant differences only for marginal bone loss (MBL) when immediate implants were placed in the mandible (I²: 15%; P = .01) and posterior zone (I²: 0%; P = .001). Conclusions: Complications and patient-centered outcomes for immediate single-implant crowns were comparable to delayed loading. Scientific evidence showed no significant difference between loading protocols for survival rates. Note that several factors could interfere with the complication events, implant failures, and MBL. The subgroup analysis showed that only immediate implants placed in the posterior mandible had a higher and statistically significant mean MBL.