| During the past decade, the development of dental implantation and parodontology has increased the need in oral and maxillofacial surgery for the substitution of lost bone. Various substances of human or animal origin or synthetic materials may be used to fill bone defects. However, none of the methods employed at present are perfect. In consequence of the fear of bovine spongiform encephalitis, nowadays there is a reluctance to utilise materials of bovine origin (Honig et al, 1999). This may also be the reason why interest in synthetic bone substitutes has increased so significantly in recent years. One of the synthetic materials is phase pure beta-tricalcium phosphate (beta-TCP). Animal experiments and clinical results have revealed that beta-tricalcium phosphate (beta-TCP) has the advantages that neither beta-TCP itself nor its breakdown products are toxic, and it does not contain viruses, prions, or other proteins. It is tissue-friendly and its transformation is not accompanied by inflammatory symptoms. Platelet rich plasma (PRP) can promote ossification through its various factors. The literature is lacking data demonstrating the benefits of a combination therapy with PRP and synthetic bone-substitutes. Therefore, the objective of the present animal experiment was defined as follows: beta-TCP was implanted in a specific part of the maxilla of a beagle dog, while in another area, located symmetrically on the other side, PRP mixed with beta-TCP was applied. This method provided an opportunity to undertake clinical, radiological and histological examinations under identical circumstances and to determine possible differences in the ossiffication process. The clinical examination showed that, after a healing time of 12 weeks, the bone defects were completely filled up with newly formed bone of similar hardness both in beta-TCP and in beta-TCP/thrombocyte suspension. beta-TCP particles could still be recognised after 12 weeks in the histological examination, but the quality of the new tissue proved to be good. In every defect, histological and histomorphometrical examinations demonstrated a picture corresponding fundamentally to bone tissue. In cases of beta-TCP+PPP grafts, the beta-TCP particles in the sections exhibited a greater degree of transformation than without PRP. beta-TCP+PRP expressed a greater level of activity in computertomography examinations. |
