Implant Survival in Immediately Loaded Full-Arch Rehabilitations Following an Anatomical Classification System—A Retrospective Study in 1200 Edentulous Jaws

This retrospective study analyzed implant survival of immediate implant-supported fixed complete denture (IFCD) treatment options (TOs) based on the level of alveolar atrophy (CC). Records of 882 patients receiving a total of 6042 implants at one private referral clinic between 2004 and 2020 were considered. The mean follow-up period was 3.8 ± 2.7 years. Cumulative implant survival rates (CSRs) were analyzed as a function of CCs and TOs according to Mantel-Haenszel and Mantel-Cox. Hazard risk ratios for implant loss were compared using Cox regression. Confounding factors were identified using mixed Cox regression models. The 2- and 5-year CSRs were 98.2% and 97.9%, respectively. Maxillary 2- and 5-year CSRs were lower (97.7% and 97.3%) compared to mandibular CSRs (99.8% and 98.6%) (p = 0.030 and 0.0020, respectively). The CC did not influence CSRs of IFCDs in the mandible (p = 0.1483 and 0.3014, respectively) but only in the maxilla (p = 0.0147 and 0.0111), where CSRs decreased with increasing atrophy. TOs did not statistically differ in terms of survival rate for a given level of alveolar atrophy. The adaption of IFCD treatments to the level of atrophy and patient-specific risk factors can result in high CSRs, even at different levels of bone atrophy.