Comparison of Radiographic and Clinical Outcomes Following Immediate Provisionalization of Single-Tooth Dental Implants Placed in Healed Alveolar Ridges and Extraction Sockets

Purpose: The primary goal of this study was to compare implant survival 12 months after immediate loading of single implants placed in healed ridges versus extraction sockets. Secondary outcomes were to compare marginal bone adaptation and soft tissue changes over time. Materials and Methods: A prospective multicenter clinical investigation was initiated to assess clinical performance of immediately loaded implants in the maxilla. Implant survival was ascertained at the time of impression making (8 to 10 weeks) and after 1 year by clinical stability. Radiographic marginal bone levels, soft tissue levels, and plaque and bleeding scores were compared with baseline values (implant placement and provisionalization). Results: One hundred thirty-nine patients received 157 implants in the maxilla. Single implants with provisional crowns were placed in extraction sockets of 55 patients (58 implants) and in healed ridges of 60 patients (65 implants). In addition, 19 patients (23 implants) required bone grafting prior to implant placement, and 11 implants in 10 patients among all groups were not immediately loaded because of insufficient initial stability after surgery. Three implants (5.2%) failed in extraction sites and one implant (1.5%) failed in a healed ridge. The mean change in marginal bone level 1 year after implant placement was 1.30 mm (SD 2.52) (gain) in extraction sockets and -0.40 mm (SD 1.43) (loss) in healed ridges. The mucosal zenith was stable or moved incisally following definitive crown placement in 83.7% of immediate implants and 87.0% of implants placed in healed ridges. Plaque and inflammation scores were low and did not differ between groups. Conclusions: The responses of local bone and soft tissues at immediately loaded implants placed in extraction sockets or healed ridges were similar. Furthermore, these 1-year results suggest that clinical management of esthetically critical soft tissue may be predictably achieved in both indications. Keywords: dental implants, immediate loading, immediate placement, single-tooth replacement