Comparison of Tissue Reaction and Osteointegration of Metal Implants between Hydroxyapatite/Ti alloy Coat : An Animal Experimental Study
PIBUL ITIRA VIVONG, MD*, ATICHAT PROMASA, DVM**, THADA LAIPRASERT,MD*, TA WEECHAI TECHAPONGWORACHAI, MD*, SOMSAK KUPTNIRA TSAIKUL, MD*, VORANUCH THANAKIT, MD***, ROBERT B HEIMANN, PhD****
Affiliation : * Department of Orthopedics, Faculty of Medicine, ** Department of Surgery, Faculty of Veterinary Science, ***Department of Pathology, Faculty of Medicine, Chulalongkorn University, Bangkok 10330, Thailand. **** Department of Mineralogy, Freiburg University of Mining and Technology, D 09596 Freiburg, Germany.
Objective : The objective of this study was to detect and analyze possible differences in bone formation, bone integration and tissue reaction between group I (uncoated Titanium), group II (Hydroxyapatite coated Titanium), and group III (Hydroxyapatite!fi02 coated Titanium) implant specimens when embedded into bony hosts.
Method : Rectangular specimens were implanted into the femoral bone of adult dogs in randomly different sites including : proximal left, proximal right, distal left, distal right. The tailor made implant specimens were inserted in 5 x 5 mm preprepared sockets. Radiographic evaluation was taken at 0, 1, 3 and 6 months. All animals were sacrificed at 3 and 6 months post implantation. The femoral bone containing implants were dissected and then prepared to be further investigated. The bone-implant interface was analyzed by H&E surface staining, radiography and scanning electron microscopy. Data concerning percentage of osteointegration and adhesiveness of hydroxyapatite layer from different kinds of implants along the entire length of each implants were collected and analyzed for evaluation of any significant differences.
Results : No osteo-integration was noted in Group I, but there was 25.57 per cent osteo integration in Group II and 28.63 per cent in Group III. No statistically significant differences were observed between Group II and Group III. However, the coating layer in Group II was found to have detached, in some area, from the metal substrate. Histologically, no adverse tissue reaction was found around any kind of implant.
Conclusion : Biocompatable bond coat is one of the methods to improve adhesive strength of hydroxyapatite coated implants. In the present study it could be concluded that, besides the improve ment in adhesiveness, the intervening Ti02 coating layer had no negative effect concerning bone formation and integration and also showed no adverse surrounding soft tissue reaction.
Keywords : Titanium, Titanium/Hydroxyapatite Coat, Titanium!Ti Alloy/Hydroxyapatite Coat
