On the formation of fibrous capsule and fluid space around machined and porous blood plasma clot coated titanium

Machined and machined submicron porous titanium, with and without a thin bl ood plasma coating (100 nm), were implanted for 7 or 28 days in subcutaneou s pockets on the back of the rat. After explantation the specimens were ana lyzed by light microscopy with respect to thickness of the fibrous capsule, the fluid space width between implants and fibrous capsule, and formation of blood vessels. The results at 7 days indicate a thinnest fluid space for the plasma clot coated porous titanium surface, and the spaces vanished at the light microscopic level after 28 days outside all the analyzed surface s. The thickness of the fibrous capsule increased outside the different sur faces at 7-28 days, and in this respect no significant differences were obs erved between the different surfaces at any time. Analysis of neovasculariz ation showed that the number of vessels and proportion of vessels in the fi brous capsule increased with time at all surfaces, except machined Ti where the number instead decreased from 7 to 28 days. The average distance betwe en the blood vessels and the fluid space increased with time for all types of surfaces. The results in the present study indicate that the healing pro cess around titanium can be modulated by porosity and thin pre-prepared pla sma coatings. (C) Kluwer Academic Publishers.