Water durability of resin bond to precious metal alloys using adhesive resins containing adhesion promoting monomers.

Adhesive resins for precious metals were prepared by adding an adhesion promoting monomer to MMA-PMMA/TBBO resin. Precious metal alloys bonded by the adhesive resin were thermocycled 0, 1,000, 2,000, or 4,000 times in water between 4 and 60 degrees C, and tensile bond strengths were measured. Debonded metal surfaces after the tensile test were analyzed based on an area of cohesive failure. Three-way ANOVA revealed that all the three parameters--adherend, adhesive monomer, and number of thermal cycles--exhibited a significant influence on bond strength. Bond strength significantly decreased with increasing number of thermal cycles except for resin with 9,10-epithiodecyl 4-vinylbenzoate (EP8VB) to Au alloy. Mean bond strength of adhesive resin with 9,10-epithiodecyl methacrylate (EP8MA), EP8VB, or 3,4-epithiobutyl 2,2-bis(methacryloyloxymethyl)propionate (EP2BMA) exceeded 22 MPa after 4,000 thermal cycles. Analysis of debonded surfaces revealed the applicability of EP8MA, EP8VB, and EP2BMA as an adhesive monomer component of adhesive resin formulations.