The auther embedded the clinically differently used direct resins to the oral submucosa of the rabbits, and compared the tissue reactions to the direct resins with that to the indirect resins. The results were as follows: 1. Direct resins showed more lympocytes infiltration than indirect resins at the early stage of the embedding, but the same degree of the appearance of lympocytes infiltration as indirect resin at the late stage of the embedding. And the formation of fibrosis around the embedding showed the irregular finidng. 2. Fibrosis of direct resin showed the tendency to be finer than indirect resin at the early stage of the embedding, but direct resin formed the similar fibers capsule to that of indirect resin at the late stage of the embedding.