LASER BONDING TECHNIQUE FOR BONE SPECIMENS USING CERAMIC PASTE
Satoshi Yamada1, Tomoki Komori1, Masaru Kanaoka2, Shigeru Tadano1,3
1Hokkaido University, Japan;
2Mitsubishi Electric Corporation, Japan;
3National Institute of Technology, Hakodate College, Japan
In orthopedic surgery, implants are widely used to fix bones until healing. The authors have developed an instantaneous bonding technique between bone and ceramics as an implant material by laser irradiation. Previously, the ceramic plate sintered with hydroxyapatite (HAp) and MgO-Al2O3-SiO2 glass powders with 80:20 wt% proportions (G-HAp powder) were immediately bonded onto the bone surface in vitro by fiber laser irradiation, generating a foam-like substance. Based on this, the current study proposed a novel technique to bond bones directly using a ceramic paste toward bone fixation. The ceramic pastes were made of G-HAp and gelatin powders with distilled water by mixing and kneading: paste A (50% G-HAp, 10% gelatin, and 40% water) and paste B (50% G-HAp, 2.5% gelatin, and 47.5% water). HAp powder and both pastes were irradiated with a fiber laser under 400 W laser powers in a second, respectively. As a result, paste A generated the foam-like substance strongly during the irradiation, suggesting that the collagen component contributes to generate the substance and to bond bones and ceramics. Using the pastes, laser bonding of two bone specimens was examined. 20 bone specimens (approximately 15×40×4 mm) were taken from bovine femurs, and a 3 mm diameter hole was drilled. The specimen was divided two parts at the center of the hole, and the divided hole was filled with the pastes. A 5 mm diameter area at the boundary of the parts including the hole was irradiated under 200 and 400 W powers. As a result, the bone specimens were bonded under all four conditions. The bonding strength was maximized to be 0.95 N under 200 W powers with paste A. It depended on the gelatin contents of the paste. The study developed the ceramic paste and demonstrated the laser bonding of bone specimens.