Effects of clasp flexure on a 4-META adhered light-polymerized composite resin

Three specimen sets of removable partial denture claps were veneered using a composite resin with 4-META onto a 50-microns aluminum oxide air-abraded surface and flexed 0.01, 0.02, and 0.03 inches for 1,500 cycles. No veneers survived intact following 0.03-inch flexures; 58% survived 0.01-inch flexures and 44% survived 0.02-inch flexures intact. There was a significant increase in the number of veneer cracks in 0.02-inch flexed clasps compared to those flexed 0.01 inch.