Objectives: Implant design and loading condition are crucial factors in determining therapeutic successes in implant dentistry. On the other hand, osteocytes are definitive cells that regulate bone quality and quantity under loaded condition. However, the effects of implant design and mechanical load on osteocytes are unclear. The aim of this study was to investigate the combination of implant design and mechanical load on osteocytes around dental implants.
Materials and Methods: Anodized Ti-6Al-4V alloy dental implants with three grooves around the neck were used. Groove designs were +60° and −60° grooves, defined as 60° in the clockwise and counterclockwise directions to a plane perpendicular to the long axis of the implant, respectively. Adult Japanese white rabbits were used. The implants with −60° grooves (n =14) were placed in the tibial metaphysis of a randomly selected side of each rabbit, and the implants with +60° grooves (n =14) were placed in the other side. A mechanical load of 50 N with a frequency of 3 Hz for 1800 cycles, 2 days/week for 8 weeks using a custom made loading device were applied. Osteocyte numbers (density) were measured using scanning electron microscopy (SEM).
Results: Osteocyte density around dental implants was almost same under unloaded condition, irrespective of implant designs. In −60° grooves, osteocyte density inside and outside area of the grooves did not change, regardless of mechanical load. In +60° grooves, osteocyte densities inside and outside area of the grooves were significantly increased under loaded condition compared with unloaded condition.
Conclusion: Implant design does not affect osteocyte networks under unloaded combination. The implants with +60° grooves are superior to the implants with −60° grooves in regard to development of osteocyte network under loaded condition.