Treatment of inflamed ferret dental pulps with recombinant bone morphogenetic protein-7

Recombinant human BMP-7 (bone morphogenetic protein-7, osteogenic protein-1 ) is osteogenic, dentinogenic and cementogenic when implanted into the appr opriate tissue in vivo. However, most studies characterizing the induction of these tissues have implanted BMP-7 into freshly surgerized, clinically h ealthy tissues. To determine if BMP-7 is dentinogenic in inflamed dental pu lps, we applied BMP-7 to inflamed ferret pulps. A single application of 5 m u g ofa commercial preparation of lipopolysaccharide (LPS) from Salmonella typhimurium directly to the coronal pulp induced a reversible mixed inflamm atory exudate of moderate intensity within 3 d. Treatment with a single app lication of 2.5, 7.5 or 25 mu g recombinant human BMP-7/mg collagen (2 mg t otal mass/tooth) induced reparative dentinogenesis in controls but not LPS treated dental pulps. These data reveal that a single application of up to 50 mu g/tooth of exogenous recombinant BMP-7 is insufficient to induce repa rative dentinogenesis in ferret teeth with reversible pulpitis. Given that pulp cells in the inflamed tissues likely retain the capacity to respond to exogenous BMP-7, it is possible that insufficient active recombinant prote in is available to induce tissue formation in experimentally inflamed denta l pulps.