Comparative Implant Stability of a Novel Implant-Porous Titanium Complex and an Implant-Porous Hydroxyapatite Complex for Bone Reconstruction Material

This study aimed to compare the implant stability of an implant-porous titanium complex with that of an implant- porous hydroxyapatite complex. Implant-porous titanium and implant-porous hydroxyapatite complexes were placed in the tibia of four New Zealand white rabbits. After 4 weeks, the implant stability quotients (ISQs) were measured. Histological observations and histomorphometric measurements were performed. There was no significant difference in the ISQ values and bone implant contact ratios between both groups. In contrast, the newly formed bone area ratios were significantly low-er in the implant-porous titanium than in the implant-porous hydroxyapatite. Histologically, osteoconduction was observed in both groups in the upper cortical bone region; however, lesser new bone was formed in the lower bone marrow region in the implant-porous titanium than in the implant-porous hydroxyapatite. In conclusion, implant-porous titanium and im-plant-porous hydroxyapatite complexes have favourable implant stability. However, osteoconduction was insufficient with the implant-porous titanium complex compared with the implant-porous hydroxyapatite complex. This may be improved by making titanium bioactive through surface treatment or other means.