An in vitro investigation of bond strength of veneering composite resin to glass fibre veil reinforced composite

Experimental light-curing polymer-monomer-gel-impregnated E-glass-fibre veil reinforced composite (i.e. a composite with randomly oriented fibres) was used as an adhesional substrate for veneering composite resin (VCR). Continuous unidirectional glass fibre composite was used as a control substrate. Both the fibre-reinforced composite substrate surfaces were ground or, optionally, the substrate surface was left untreated (containing oxygen-inhibited resin layer) before attaching to the VCR. No adhesive resin was used between the composites. Shear bond strength of VCR to the substrate was determined for dry and thermocycled specimens. The results of this study suggested that the VCR can better be bonded to the randomly oriented veil fibre-reinforced composite substrate than to the continuous unidirectional fibre-reinforced composite substrate.