INFLUENCE OF COMPLIANCE OF THE SUBSTRATE MATERIALS ON POLYMERIZATION CONTRACTION STRESS IN THIN RESIN COMPOSITE LAYERS

The present study determined in a laboratory set-up the influence of c ompliance of the substrate material on polymerisation contraction stre ss for various thicknesses of bonded dental resin composite films. Whe n the compliance of the tensilometer set-up was increased from 0.029 m u m MPa(-1) to 0.150 mu m MPa(-1), the contraction stress in films wit h a thickness of 100 mu m and a diameter of 5.35 mm decreased from 22 to 7 MPa. For the 700 mu m samples the stress decreased from 12 to 11 MPa. It was concluded that if compliance from the substrate materials is possible, a thinner resin composite film may effect a more reliable bond. (C) 1997 Elsevier Science Limited. All rights reserved.