Timing of Loading - Immediate, Early, or Delayed - in the Outcome of Implants in the Edentulous Mandible: A Prospective Clinical Trial

Purpose: To report on the implant outcome of delayed, early, and immediate loading of implants in the edentulous mandible in a prospective controlled study. Materials and Methods: On a consecutive basis, the first 10 patients received an overdenture retained by 2 ball attachments 4 months after implant insertion (delayed), and the next 10 patients received an overdenture 1 week after implant surgery (early). The next 10 patients were treated with a fixed prosthesis on 3 implants (Brånemark Novum) either the day of or the day after surgery (immediate). All patients were followed for 1 year; half were followed for 2 years. Measures of assessment for this prospective clinical trial included monitoring of loading at prosthesis level (bite fork) as well as at the abutment level (strain gauges), 3-dimensional imaging of marginal bone remodeling, and implant stability. Results and Discussion: One patient in each OD group lost both implants. The losses occurred 6 months after loading in the delayed group and 1 month after loading in the early group. In the immediate group, 1 patient lost both distal implants 5 months after loading. In 2 other patients, 1 distal implant failed after 1 year of loading. Maximal bite forces increased over time for all groups. Marginal bone loss was the highest for the immediate group, while no differences in implants stability were observed between the 3 groups after 1 year of loading. Conclusions: According to this prospective controlled clinical trial, the results achieved with implants loaded early were comparable to those achieved with implants loaded after a delay. Distal implants are at higher risk for failure in the immediate loaded protocol. (Clinical Trial) Keywords: early loading, immediate loading, occlusal bite forces, 3D imaging of bone remodeling