The paper reports on the structural morphology of the interface between a porous glass ceramic (A3) based on the SiO2-CaO-MgO-K2O-Na2O-P2O5 system and the surrounding bone in rat tibias. After devitrification the glass was composed of diopside and calcium phosphate phases.
In physiological environment, porous implants are highly favourable, as their open structure secures large surface areas for biochemical processes.
The interfaces formed after implantation for 6, 8 and 12 weeks were examined by analytical scanning and high-resolution transmission electron microscopy.
The new bone was found growing in direct contact with the implants. Gradual degradation processes of the A3 glass ceramic encouraged the bone ingrowths into the pores of the implanted material. At 12 weeks, most of the pores were filled with osseous tissue and vascularization process of the implant was well established.
Significant morphological remodelling at the interface formed a disorganised bone tissue structure, followed by lamellar bone arrangement. Advanced cellular activity and collagen fibrils deposition were also observed.
Selected area diffraction pattern of the interface displayed distinctive spots from the crystalline implant in addition to characteristic arcs associated with the mature bone.
In the area of mature bone, Ca/P ratio reached value for pure HA, while inside of the material, the ratio was consistently higher at 2.00. The reason for this increased ratio could be continuous release of Ca ions from the implant. Secondly, the bone could enrich itself with carbonate ions, producing carbonate enriched HA of variable CO32- content
In conclusion, the porous A3 material demonstrated bioactive-degradable properties right at the interface and inside the whole volume of the implant. The material is expected to be satisfactory in applications related to repair or replacement of living bone, where a progressive substitution of the implant is required.