Bone -bonding behavior of porous titanium implant after alkali and heat treatments

摘要

This study was carried out to investigate the effects of alkali and heat treatments on the bone-bonding behavior of porous titanium implants. A porous titanium rod, 6 mm in diameter, was manufactured. This rod had 4.6 mm solid core and 0.7 mm-thick porous outer layer using pure titanium plasma-splay technique. This rod was cut transversely into pieces of 13 mm long. Three kinds of porous implants were prepared from these pieces: 1) control; as manufactured (CL), 2) AW-glass ceramic bottom coated (AW), 3) Alkali- and heat-treated (AH) (5 mol/L NaOH 60deg C for 24 h and 600 deg C 1h). The implants were inserted into canine femora hemi-transcortically. At 4 and 12 weeks after implantation the bone-bonding shear strengths of the implants were analyzed with push out test and histological and histomorphometrical analysis were also performed. At 4 weeks the AH implants showed significantly higher shear strength than the CL implants. At 12 weeks there was no significant difference among the bonding strengths of the three types of the porous implants. There was no difference in bone ingrowth into porous portion of the three types of the implants at both 4 and 12 weeks, while direct bont contact with implant surface was significantly higher in the AH implants than the CL and AW implants both at 4 and 12 weeks. In conclusion, alkali and heat treatments can provide the porous titanium implants with earlier stable fixation.