Étude de la colonisation par des ostéoblastes humains de métaux poreux à base de nitinol ou de tantale dans un modèle de culture cellulaire tridimensionnelle

Acting as scaffolds for cell spreading and new tissue ingrowth once implanted into living tissues, porous materials have been used for several years for reconstructive surgery. In the field of dentistry and orthopedics, the biomechanical requirements for the implants have lead to an extensive use of biocompatible alloys. However, in a solid form these alloys have always exhibited inadequate fixative properties in the surrounding bone. Recent technologies allow the manufacturing of highly porous metallic open cell structures, biologically and biomechanically compliant. Two of these porous metals appeared particularly interesting for the design of novel dental implants: a porous titanium-nickel alloy (NiTi) and a porous tantalum structure. The purpose of the present study was to assess in vitro the invasion level of these porous materials by human osteoblasts, by the use of a three-dimensional cell culture system. Bone cell growth was measured by the MTT test, whereas cell infiltration and morphology throughout the porous scaffolds were examined by confocal microscopy. Our results indicate that porous NiTi and porous tantalum behave as suitable substrates for the attachment and ingrowth of human osteoblasts. Furthermore, the tantalum porous structure appeared more favorable to bone cell morphology and infiltration. These in vitro results are predictive for a good in vivo osseo-integration of implants made with these porous metals, as already reported in several orthopedic applications.