Influence of the structure of three corals on their resorption kinetics.

The aim of this study was to investigate the influence of the structure of corals on their resorption kinetics after implantation in subcutaneous areas. Three types of coral (Porites astreoides, Montastrea annularis and Dichocoenia stokesi) identical in composition but different in structure were implanted for periods of 1 and 2 months in subcutaneous sites in OF1 mice. The resorption of the implants was studied by means of qualitative (histology, scanning electron microscopy, fluorochrome labelling method) and quantitative approaches (gravimetric method). The results of the qualitative study revealed a process of irregular deterioration of the coral, linked to the detachment of crystals at the surface of the implant. The results of the quantitative study showed that the speed of resorption increases with the implantation time and the open porosity of the coral. These reactions are explained by the increase of the surface exchange area in contact with factors responsible for resorption: biological medium and cells. When considering the choice of coral as a bone substitute, these factors must be taken into account to allow the in situ maintenance of the implant over a sufficiently long period of time according to the clinical situation.