LONG-TERM BEHAVIOR OF A HYDROXYAPATITE COLLAGEN-GLYCOSAMINOGLYCAN BIOMATERIAL USED FOR ORAL-SURGERY - A CASE-REPORT

A composite biomaterial consisting of hydroxyapatite with a collagen-glycosaminoglycan coating was studied for evaluation of the osteogenesis after long-term implantation in a human freshly extracted alveolar socket. The ultrastructural investigations were realized using scanning and transmission electron microscopy on cryofractured and embedded biopsy specimens. Crystallographic data were obtained by X-ray diffraction and high resolution transmission electron microscopy, The biomaterial (Biostite(R)) was shown to consist of irregularly shaped mineral particles of high dispersity, each made up of numerous single hydroxyapatite crystals. In addition, this crystalline phase appeared to be incorporated in a fibrous network. 42 months after implantation only some intercrystalline spaces of the hydroxyapatite aggregates were invested by newly formed bone-like apatite crystals. Moreover, this investigation showed clearly well-mineralized bone interfacing with some implanted aggregates, whereas other hydroxyapatite particles were still surrounded by soft tissue. No evidence of resorption of implanted material was found and the synthetic hydroxyapatite crystals appeared to remain unaltered by long-term implantation.