Keratin Hydrogel Increases Osseointegration of Neoss Implants in Cancellous Bone

Keratin hydrogel has been shown to improve neuroregeneration, haemostasis, and healing. A non-quantitative pilot study showed improved osseointegration of titanium dental implants after 4 weeks in an animal model (Campbell, 2009). Objective: Quantify the effect of Keratec Hydrogel™ on osseointegration of titanium implants. Methods: Twenty 3.5mm x 7mm bimodal-surface titanium implants (Neoss Australia Ltd) were placed bilaterally into femoral condyles of 10 sheep, 1 test and 1 control implant/animal. Test implants were coated with 1ml of Keratec Hydrogel™ immediately before placement. Resonant frequency analysis (RFA) was measured in implant stability quotient (ISQ) using Mentor II (Osstell AB, Sweden) at surgery and sacrifice after 1 month unloaded healing. Implants were resin-embedded and ground sections digitalised. Mean bone-implant contact (%BIC) was measured for the best-three consecutive threads from the two-most-central sections and compared using Mann-Whitney U test. Results: One of 20 implants showed evidence of failure. RFA for both groups showed small but significant improvements over 1 month. Control implant RFA increased from 72.3 ±SD 3.5 to 76.5 ±4.2, p=0.04; test implant RFA increased from 75.5 ±3.2 to 80.4 ±1.4, p=0.002. RFA did not differ between test and control implants at surgery (p= 0.07) but control was statistically significantly lower (76.5 ±4.2) than test (80.4 ±1.4) after 1 month (p=0.04). Keratec Hydogel-coated implants showed a marked increase in % BIC (58.1 ± 4.6%) compared to the control implants (34. 4 ± 7.5%) which was statistically significant (p = 0.016). Conclusions: Surface treatment of unloaded bimodal titanium implants with a keratin hydrogel significantly improved clinical and histomorphometric measurements of osseointegration in an ovine model for cancellous trabecular Type IV bone four weeks post-surgery. Further testing in preclinical models with cortical bone and in immediately-loaded clinical conditions is advocated before human clinical trials. Acknowledgement: Funded by Neoss Australia (Ltd), KOSEF R01-2005-000-10461-0, R01-2004-000-10545-0 & R01-2007-000-20488-0.