Ricinoleic acid polyurethane polymer behaviour, implanted subperiostic in rat's mandibular angles was studied. liventy Rattus novergicus (Alhinus rodentia mammalia, cepa Wistar) were divided in for groups of five animals each. The polymer polyurethane, added of calcium carbonate, was implanted at mandibular angle of them. One animal from and 90 days after surgery. Histological examination showed the stability of the implant, the almost total absence of inflammatory response, the fibrous capsule formed surrounding the implant, and bone neoformation. According the experimental model, we concluded that the subperiostic implanted ricinoleic acid polyurethane polymer did not unleash a significant later inflammatory reaction, it has took to the development of a districted fibrous capsule, with evolution for bone neoformation. Signals of rejection, exposition or expel of the implant were not registered.