Immediate functional loading of single implants: a multicenter study with 4 years of follow-up

Background: In the current scientific literature there are only few studies on the immediate functional loading of single implants. Aim: To present the 4-year survival rate, complication rate and peri-implant marginal bone loss (PIMBL) of immediately loaded single implants inserted in healed ridges and fresh post-extraction sites. Methods: Six centers were involved in this prospective study. The surgical and prosthetic protocol was defined in detail, before the start of recruiting patients. Recruitment of patients and performance of surgeries took place between February 2012 and February 2013. Criteria for inclusion were single-tooth gaps in healed ridges and fresh post-extraction sockets. All fixtures (Anyridge®, Megagen Corporation, Gyeongbuk, South Korea) were functionally loaded immediately after insertion and followed for a period of 4 years. Outcome measures were implant survival, complications, PIMBL. Results: Forthy-six patients (between 18 and 73 years of age) were selected. In total, 57 fixtures were placed (10 in fresh post-extraction sockets). After 4 years of functional loading, only one fixture was lost, therefore high survival rates (97.6% patient-based; 98.1% implant-based) were reported. In addition, a limited incidence of biologic (4.8% patient-based; 3.8% implant-based) and prosthetic (9.7% patient-based; 7.6% implant-based) complications was reported. The overall 4-year PIMBL amounted to 0.38 ± 0.21 mm (healed ridges 0.4 ± 0.21 mm; fresh post-extraction sockets 0.33 ± 0.20 mm). Conclusions: Loading single implants immediately seems to be a highly successful treatment procedure. However, long-term data are needed to confirm these positive outcomes.