EFFECT OF FILLER CONTENT ON MECHANICAL STRENGTH IN BIS-GMA-BASED RESINS WITH URETHANE LINKAGES

Bis-GMA-based visible-light-cured resins containing urethane linkages exhibited improved hardness and strength by addition of filler to the unfified resins. The urethane monomers in the resins strengthened the resin matrix, exhibiting an increased Shore hardness value. Urethane monomer derived from 2HEMA and N3500 was more effective than that from 2HEMA and HT. The increased strength in the resin matrix occurred after storage in water at 37 degrees C. Addition of filler to bis-GMA-based resins increased compressive strength (110 MPa as the maximum), while diametral strength values of 20 MPa were obtained.