DNA/protamine complex paste for an injectable dental material.

A DNA/protamine complex powder was prepared by reaction between DNA and protamine sulfate solution with stirring in order to develop a new injectable biomaterials for dental therapy. The powder of DNA/protamine complex became paste by kneading the complex powder and distilled water. Complex formation was confirmed by FT-IR measurement. The complex paste had a porous structure and its viscosity was approximately 280.1 Pas. The paste could easily pass through a needle of 0.25 mm internal diameter. It seemed that DNA/protamine complex paste has suitable viscosity for clinical use as an injectable biomaterial. Although, the complex paste delayed the growth speed of Staphylococcus aureus, Pseudomonas aeruginosa, Porphyromonas gingivalis and Prevotella intermedia for limited periods, it cannot kill and inhibit growing bacteria. The complex paste disk showed a mild tissue response and gradually degraded after the implantation into the soft tissue of rats. These results suggested that this DNA/protamine complex paste could be a useful material for a biodegradable biomaterial. In particular, this paste will be applicable as an injectable biomaterial using syringe for the repair of defects of living tissue, GBR treatment and/or GTR treatment in dentistry.