The issue of bioresorption of the Bio-Oss xenogeneic bone substitute in bone defects.

Bone grafts and bone substitute biomaterial implemented in guided tissue regeneration should undergo the process of biological decomposition in the recipient's system. The aim of this work is the presentation of current views concerning the issue of Bio-Oss bovine bone bioresorption and their juxtaposition with the results of the author's own research. The work presents histopathological and immunohistochemical tests of the xenogeneic Bio-Oss preparation from biopsies carried out 30 months after implantation. It was observed that the preparations contained correct bone neighbouring remnant particles of Bio-Oss, intratrabecular fibromatosis around the implant, abundant vascularisation, absence of osteoid and of active inflammatory process. A small number of T and B lymphocytes was detected. The results obtained in the above-described case testify to the descending character of the inflammatory infiltration 30 months after the implementation of Bio-Oss and efficient restoration of the bone. The prevalent view in literature is that Bio-Oss is resorbable biomaterial. However, there are also reports questioning this view as remnants of Bio-Oss have been detected even 44 months after implantation into the bone defect. In the author's own cases, Bio-Oss remnants could be observed 30 months after implanting. It seems that although the creation of new bone structure is indisputable, the process of biological decomposition of Bio-Oss should be described as slow bioresorption.