Bone regeneration in novel porous titanium implants

Abstract

The objective of this study was to evaluate the in vivo performance of the novel press-fit dental implant fabricated via electron beam melting (EBM, Southern Methodist Univ.) and compare it to a commercially-available porous-coated press-fit dental implant (Endopore, Innova Corp.). Twelve cylindrical shaped implants 3 mm in diameter x 5 mm long were made by EBM (Southern Methodist Univ.) using Ti6Al4V ELI alloy. Twelve commercial implants (Endopore, Innova Corp.) of the same geometry were used as controls. Samples were implanted in rabbit tibia and retrieved six weeks postoperatively. Six specimens from each implant type were embedded undecalcified, sectioned, and stained with toluidine blue (Sigma) for histomorphometry analysis. Bone-to-implant contact (BIC) was measured. On the six remaining samples from each implant type, the mechanical properties were evaluated by pushout test on a material testing machine. The samples were loaded at a loading rate of 1 mm/min. The pushout strength was measured and the apparent shear stiffness was calculated. The results were analyzed with a paired-t test. The histology shows osteointegration of surrounding bone with both implant types. Bone was found to grow into the porous space between the beads. Both the Endopore (Innova Corp.) and the EBM (Southern Methodist Univ.) showed similar BIC. The mean BIC for the Endopore (Innova Corp.) and EBM (Southern Methodist Univ.) implant were 35 ± 6% and 32 ± 9%, respectively. It failed to reach statistical significance (p > 0.05). The peak pushout force for Endopore (Innova Corp.) and EBM (Southern Methodist Univ.) implants were 198.80 ± 61.29 N and 243.21 ± 69.75 N, respectively. The apparent shear stiffness between bone and implant for the Endopore (Innova Corp.) and EBM (Southern Methodist Univ.) implants were 577.36 ± 129.99 N/mm; and 584.48 ± 146.63 N/mm, respectively. Neither the peak pushout force nor the apparent shear stiffness of the implants was statistically different between the two groups (p > 0.05). The results suggest that the implants manufactured by EBM (Southern Methodist Univ.) perform equally well as the commercial implant Endopore (Innova Corp.) in this current animal model.