Early bone formation in furrows at titanium implants. A study in the rabbit tibia

Aim Previous studies have shown a preference for bone formation in macroscopic furrows as compared to other parts of the implant surface. The aim of the study was to describe the early events of bone integration of furrowed oxidized titanium implants. Materials and Methods New Zealand white rabbits and 54 implants were used in the study. The test oxidized implants had a 110 μm wide furrow added to the superior flank whilst the control oxidized implants had no furrow. The implants were retrieved after 7, 14 and 28 days for light microscopy and for micro-CT evaluation. Results The bone contact and bone area values increased with time for all implants. A statistically significant preference for bone formation in the furrows was seen for test implants and for the inferior thread flank for control implants compared to the opposing superior thread flank. The 3D reconstructions from micro-CT showed bone formation as thin rims along the implant surface either continuous or as solitary rims. Conclusion It is concluded, that bone formation is observed more often at the lower flank and in macroscopic furrows at the threads than opposing upper flanks of oxidized titanium implants. This was more marked at seven days than later time points and in areas with no primary contacts with adjacent host bone. Bone integration of the implants seemed to occur by bone condensation directly at and along the implant surface and following the path of the implant threads.