Immediate Occlusal Loading of One-Piece Zirconia Implants: Five-Year Radiographic and Clinical Evaluation

Purpose: To evaluate radiographic and clinical outcomes of immediate occlusally loaded one-piece zirconia implants after 5 years of follow-up. Materials and Methods: This longitudinal clinical investigation included patients older than 18 years, in need of implant-supported single-unit dental rehabilitations. One-piece zirconia implants were placed in healed and postextraction sites and immediately restored with provisional crowns in light occlusal contact. Definitive zirconia-ceramic restorations were delivered 3 to 4 months after surgery. Primary estimated outcomes were implant survival and success. Periapical radiographs were taken at implant insertion (T0), after 1 year (T1), and after 5 years (T2) to assess marginal bone loss (MBL). Probing depth (PD), modified Bleeding Index (mBI), modified Plaque Index (mPI), and gingival recession (REC) were also measured repeatedly for implants and reference teeth. Changes in parameters over time were assessed using the Wilcoxon signed rank test. In addition, multilevel mixed effects linear and logistic regression models were fitted to take into account within-subject correlations and baseline values. Results: Thirty-two implants were inserted in postextraction and healed sites (n = 16 of each) in 17 patients. One immediate implant was lost after 3 months, and one patient with one implant dropped out after T1. Therefore, the cumulative survival rates were 96.9% at T1 and 96.8% at T2 (4.3 to 6 years). No significant differences were observed in mean MBL between immediate and delayed implants at either T1 or T2. Moreover, different baseline parameters (sex, arch, implant location, smoking habits, grafting) did not show any influence on MBL at either time. In general, for all clinical parameters (PD, mBI, mPI, REC), implants seemed to perform similar to if not better than natural teeth. Conclusion: Radiographic and clinical evaluations after 5 years showed satisfactory amounts of MBL and acceptable soft tissue health. Palabras clave: immediate loading, marginal bone loss, occlusal loading, one-piece implant, zirconia