Immediate and early loading of Straumann implants with a chemically modified surface (SLActive) in the posterior mandible and maxilla: 1-year results from a prospective multicenter study

Objective: Immediate and early loading of implants can simplify treatment and increase patient satisfaction. This 3-year randomized-controlled trial will therefore evaluate survival rates and bone-level changes with immediately and early loaded Straumann implants with the SLActive surface. Material and methods: Partially edentulous patients >= 18 years of age were enrolled. Patients received a temporary restoration (single crown or two to four unit fixed partial denture) out of occlusal contact either immediately (immediate loading) or 28-34 days later (early loading group), with permanent restorations placed 20-23 weeks after surgery. The primary endpoint was change in crestal bone level from baseline (implant placement) to 12 months; the secondary variables were implant survival and success rates. Results: A total of 383 implants (197 immediate and 186 early) were placed in 266 patients; 41.8% were placed in type III and IV bone. The mean patient age was 46.3 +/- 12.8 years. Four implants failed in the immediate loading group and six in the early loading group, giving implant survival rates of 98% and 97%, respectively (P = NS). There were no implant failures in type IV bone. The overall mean bone level change from baseline to 12 months was 0.77 +/- 0.93mm (0.90 +/- 0.90 and 0.63 +/- 0.95mm in the immediate and early groups, respectively; P<0.001). However, a significant difference in implantation depth between the two groups (P<0.0001) was found. After adjusting for this slight difference in initial surgical placement depth, time to loading no longer had a significant influence on bone-level change. Significant influence was found for: center (P<0.0001), implant length (P<0.05) and implant position (P<0.0001). Bone gain was observed in approximately 16% of implants. Conclusions: The results demonstrated that Straumann implants with the SLActive surface are safe and predictable when used in immediate and early loading procedures. Even in poor-quality bone, survival rates were comparable with those from conventional or delayed loading. The mean bone-level change was not deemed to be clinically significant and compared well with the typical bone resorption observed in conventional implant loading.