Resorption of corals implanted in diffusion chambers

Natural coral is a resorbable bone substitute currently used in osseous surgery. The action of cellular and interstitial fluids has been incriminated as a possible agent for coral resorption but it has not been possible to discriminate the importance of either factor. The aim of this study was to compare the resorption speed of the coral implant in contact only with biological fluids (coral dishes placed inside diffusion chambers closed with two filter membranes 1.2 μm pore size) or in contact with biological fluids and cells (coral dishes placed inside diffusion chambers closed with the above filters but with holes made with a 22 G needle or coral dishes in direct contact with soft tissue). Qualitative (SEM) and quantitative (gravimetric) results showed that the implants in contact with cells were resorbed faster than those in contact only with biological fluids. The cells in contact with the implant were mainly multinucleated giant cells and some were Trap +. TEM showed multinucleated cells with a ruffled border but without a clear zone or intracytoplasmic inclusions distinguishing them from osteoclasts. With only biological fluids, the latter intervened to a moderate extent in the resorption of coral implants in which the cellular action appears to be dominant. However, this action does not seem to be attributable to osteoclasts.