Biocompatibility of the polyurethane resin of the castor bean inserted into the alveolar bone of the dog.

The biocompability of the polyurethane resin of the castor bean (Ricinus vulgaris) was studied following its insertion into the alveolar bone of dogs, after extraction of their premolar teeth. The resin was left to polymerise in the dental alveolus. Excess of material due to polymerisation was removed and polishing was employed to smooth and adapt the occlusal surface to the margins of the alveolar bone. This allowed a perfect suture of the mucosa together with the periosteum. The resin remained in the dental alveolus for 90 days. It was observed that the polyurethane was replaced by osteoid and bone tissues and no immune or inflammatory reactions were detected. There has been work on and discussion about the use of the polyurethane in grafts, prostheses and orthoses. Attention was paid to all the surgical steps, in particular the preservation of the periosteal integrity. Further research is being followed in our Department in order to test the biocompatibility of the material presented in this paper when used together with metallic or ceramic implants.