[Studies of dental methacrylic resin. (Part. 6) Adhesive strength of self-curing methacrylic resin to polymethylmetacrylates with various cross-linking density. (author's transl)].

The adhesive property of dental acrylic resin to resin teeth and denture base resins is an important property, in the case of preperating, repairing and rebasing denture. Then, as models of denture base resin and resin tooth, heat-curing methacrylic resins which were cross-linked with three kinds of polyethylene glycol dimethacrylate, i.e., EDMA, tri-EDMA, nona-EDMA, were prepared, and the tensile adhesive strengths of self-curing methacrylic resin to them were examined. The results were as follows. 1) The tensile adhesive strength under the dry condition was dependent on cross-linking density of adherent resin, and decreased according to the increase of concentration of cross-linking agent added in adherent resin. 2) The greater the number of chain members of cross-linking agent used to adherent resin was, the higher the adhesive strength was. In particular, the adhesive strength to adherent resin added with nona-EDMA in concentration from 16.7 to 30 mole%, agreed with the tensile strength of adherent resin itself indicating a favourable adhesion. 3) The adhesive strengths under the wet condition, that is, when specimens were immersed in water at 37 degrees C for 21 days, decreased from 30 to 50%, compared with that under the dry condition.