[Animal study of the bone substitute material Ostim within osseous defects in Göttinger minipigs]

The aim of this study was to examine Ostim, a nanocrystalline hydroxyapatite suspension, with regard to its bio- and osteocompatibility, rate of resorption and remodeling dynamics within osseous defects.

Ostim was implanted in a randomised fashion into the proximal metaphysis of either the right or the left tibia of 18 Göttinger minipigs.

Based on microradiographs and histological examinations Ostim showed biocompatibility, bioactivity and osteoconductivity. This substitute material exhibited osseous integration. The degradation process stopped after six weeks. With regard to osseous regeneration within the defects, there were no significant differences between the time intervals of follow-up. Ostim could still be detected in significant amounts after one year with no complete resorption.

A restitutio ad integrum could not be observed in spite of the histological evidence of the above-described reactions within the implantation site. A thorough osseous incorporation seemed to impede the degradation of the bone substitute material. The paramount goal is to improve the biological behaviour in favour of a higher rate of degradation.