Peri-implant bone reaction to immediate, early, and delayed orthodontic loading in humans

Seventeen endosseous titanium implants were placed in completely edentulous jaws of 15 patients. The implants were loaded immediately or after 2 or 6 months, with 100 g orthodontic force. Three weeks later, the implants were removed and histologically analyzed. All of the immediately loaded implants, along with three of the eight that were loaded after 2 months, were lost. The remaining implants were stable until the end of the study. Histologic analysis of the retrieved implants showed bone remodeling in the cortical bone, thickening of the bony trabeculae by new lamellar bone deposition, and microcalli of woven bone or a lattice of woven bone formation around some implants that had been placed in soft bone. Tetracycline labeling revealed an elevated amount of newly formed bone. If further studies prove that a controlled application of orthodontic force, before application of occlusal loading, is able to rapidly enhance the density of soft peri-implant bone, we will have a powerful and precise tool to improve the rate of implant success.