title: Osseointegration of Ti-6Al-4V alloy implants with a titanium nitride coating produced by a PIRAC nitriding technique: a long-term time course study in the rat.
abstract: This study examined bone tissue responses to Ti-6Al-4V alloy implants with a hard TiN coating applied by an original powder immersion reaction-assisted coating (PIRAC) nitriding method. Progression of implant fixation in the distal epiphysis and within the medullary cavity of the rat femur was evaluated between 3 days and 6 months postimplantation by scanning electron microscopy, oxytetracycline incorporation, and histochemistry. After 6 months, successful osseointegration was achieved in both epiphyseal and diaphyseal sites. Throughout, implant portions located within the epiphysis remained in close contact with bone trabeculae that gradually engulfed the implant forming a bone collar continuous with the trabecular network of the epiphysis. In the diaphysis, woven bone was first formed within the marrow cavity around the implant and later was replaced by a shell of compact bone around the implant. In general, higher osseointegration rates were measured for TiN-coated versus the uncoated implants, both in the epiphysis and in the diaphysis. In conclusion, our findings indicate an excellent long-term biocompatibility of TiN coatings applied by the PIRAC nitriding technique and superior osteoinductive ability in comparison with uncoated Ti-6Al-4V alloy. Such coatings can, therefore, be considered for improving the corrosion and wear resistance of titanium-based orthopedic implants.
authors.affiliation: 1Department of Anatomy,Canadian Memorial Chiropractic College,Toronto,ON M2H 3J1,Canada.
authors.forename: Guy
authors.initials: G
authors.lastname: Sovak
authors.affiliation: 2The Faculty of Materials Engineering,Technion-Israel Institute of Technology,Haifa 31096,Israel.
authors.forename: Irena
authors.initials: I
authors.lastname: Gotman
authors.affiliation: 3Department of Anatomy and Cell Biology, The Bruce Rappaport Faculty of Medicine,Technion-Israel Institute of Technology,Haifa 3200003,Israel.
authors.forename: Anna
authors.initials: A
authors.lastname: Weiss
mesh_terms: D000497:Alloys; D000818:Animals; D020099:Coated Materials, Biocompatible / Q000737:chemistry*; D005260:Female; D008422:Materials Testing; D016348:Osseointegration; D019736:Prostheses and Implants; D051381:Rats; D017208:Rats, Wistar; D013997:Time Factors; D014025:Titanium / Q000737:chemistry*
chemical_list: D000497:Alloys; D020099:Coated Materials, Biocompatible; C031462:titanium alloy (TiAl6V4); C041500:titanium nitride; D014025:Titanium
keywords: rat femur