Influence of Implant Neck Design on Bone Formation Under Mechanical Repetitive Loading: Histomorphometric and Microcomputed Tomographic Studies in Rabbit Tibiae.

PURPOSE: The aim of this study was to investigate effects of implant neck design on the original concept of osseointegration and bone formation when applying mechanical repetitive loading by bone-integrated implants.

MATERIALS AND

METHODS

Twenty-eight anodized Ti-6Al-4V alloy implants with +60° or -60° grooves in the implant neck were placed in the proximal tibial metaphysis of 14 rabbits. Fourteen implants received mechanical repetitive loading along the long axis of the implant for 8 weeks at 12 weeks after implant placement. The remaining 14 implants received no loading. Histomorphometric and microcomputed tomographic analyses were then performed.

RESULTS

No effect of neck design was observed without mechanical loading, whereas osseointegration around the +60° grooves was upregulated with mechanical loading. Calculated load effects on bone structure around the implant neck with +60° grooves were larger when compared with the -60° grooves under mechanical loading.

CONCLUSIONS

These findings indicate that the establishment of osseointegration and bone formation around the implant neck with +60° grooves is superior to those with -60° grooves under loaded conditions.