Determination of bioceramic filler distribution and porosity of self-reinforced bioabsorbable composites using micro-computed tomography

A micro-computed tomography (μ-CT) image analysis was used in the micro-structural analysis of self-reinforced bioabsorbable osteoconductive composites. The composites studied were known to have a porous structure, but the total porosity of these composites had not been measured due to lack of interconnected pores. The micro-structure of the composites studied has previously been estimated using scanning electron microscopy (SEM). This yielded a very rough estimation of the micro-structure based only on the surface estimate and thus more precise μ-CT image analyses of the total porosity and volumetric filler distribution were done. The present study was performed on five different composites manufactured with either single-screw or twin-screw extruder. All the samples had the same bioabsorbable matrix polymer, poly-l/dl-lactide 70/30. The filler material was either bioactive glass (BaG) 13-93 or β-tri calcium phosphate (β-TCP). The results illustrate the possibility of μ-CT image analysis for analyzing the micro-structures of the self-reinforced bioabsorbable osteoconductive composites. Especially the three-dimensional volumetric analysis of the filler particle distribution inside the composite showed results not received before.