In Vivo Response of Bioactive Interconnected Porous Titanium Foams Produced by Powder Metallurgy Route with Osteoconduction Properties for Vertebrae Implant Applications

摘要

Titanium (Ti) is the most widely used material for bone substitution, due to its biocompatibility andmechanical properties. The aim of this study was to produce bioactive Ti foam for both improve thebiological and mechanical properties of Ti and to evaluate its in vivo osseointegration properties.In the present study, porous Ti implants were produced by powder sintering route. Samples withdifferent porous diameter and interconnectivity channels were produced varying the concentrations ofNaCl as space holder in order to select the proper conditions to achieve optimal mechanicalproperties. Surface bioactivation treatment was performed by a thermo-chemical treatment on thewhole porous scaffold in order to further stimulate the generation of a suitable apatite layer on theinterconnected porosity surface when implanted. The mechanical properties of the bioactive Ti foamwere evaluated by static (compression) and dynamic (fatigue) mechanical tests. The bioactive andnon-activated Ti foams were implanted in a critical-size defect drilled in the tibiae of 16 adult femaleNew Zealand rabbits. Histological evaluation was performed 4 and 12 weeks after implantation. Theosseointegration was evaluated on SEM micrographs by determining the BIC contact and the bonepenetration (ingrowth).Materials with 55% interconnected porosity were the ones fitting best mechanical properties similar tohealthy bone. Bone ingrowth was observed inside all the implants analyzed on macroporous andthrough interconnected porosity as well as BIC was successfully achieved at the scaffold surface.Bioactive foams showed better results than non-treated ones.