Cells and Materials


In this study, we evaluated the effect of PEO/ PBT proportion on the behavior of a range of PEO/ PBT segmented copolymers (Polyactive) during subcutaneous and intrabony implantation in the rat. It was demonstrated that varying the PEO proportion affected degradation, calcification and bone-bonding. The PEO/PBT 70/30 and 60/40 showed extensive degradation after 1 year, PEO/PBT 55145 an intermediate degradation, and the 40/60 and 30170 copolymers showed little and hardly any degradation respectively. PEO content also affected the degree of calcification . PEO/PBT 70/30 showed extensive and early calcification whereas almost no calcification was seen with PEO/PBT 30170. Since calcified sites at the periphery of the polymeric implants were locations of preference for bone-bonding to occur, PEO/PBT proportion also influenced bone/PEO/PBT interactions. The materials with the highest PEO content most frequently showed morphological indications of bone-bonding , while the material with 30 % PEO showed no bone/biomaterial contact. The differences in bone-bonding activity were also reflected by the occurrence of an electron. dense zone at the bone-biomaterial interface which was morphologically similar to that observed for calcium phosphate ceramics.