Five-year cohort prospective study on single implants in the esthetic area restored using one-abutment/one-time prosthetic approach

Purpose: This study was aimed to investigate, over 5 years, bone response to "one-abutment onetime" (OA-OT) protocol in the restoration of implants inserted in the anterior maxilla. Additionally, influence of soft tissue biotype in the bone remodeling was investigated. Materials and Methods: From January 2011 to January 2012, all consecutive patients presented with a hopeless tooth in the maxillary area between canines were enrolled. Post-extraction ridge preservation was performed. After 6 months, implant was midcrestaly inserted and intraoperative impression was taken. Two months thereafter an immediate definitive abutment with a provisional crown was inserted. At final crown connection, patients underwent a standardized periapical radiograph (T0). At 12 (T1), 24 (T2), 36 (T3), 48 (T4), and 60 (T5) months, radiographic follow-up and clinical control were carried out. Independent sample t-test was conducted to compare bone loss at different times. To detect the potential role of biotype, groups (thick TK vs thin TH) were compared by analysis of variance with general linear model. Results: Twenty-five patients were enrolled, but only 22 patients concluded the study. The radiographic analysis showed a stable longitudinal condition of bone levels after the first-year significant increasing (0.17±0.25mm, 0.33±0.25mm, 0.28±0.27mm, 0.25±0.26mm, 0.31±0.35mm, and 0.31±0.29mm, respectively at T1, T2, T3, T4, and T5). No statistical significant differences in bone loss among the two groups TH vs TK over the time (P=0.952) were demonstrated. Conclusion: Results showed that the OA-OT approach allow to obtain stable bone levels.