Resin-based luting agents and color stability of bonded ceramic veneers

Abstract Statement of problem The type of resin-based luting agent might influence the color stability of ceramic veneers. Purpose The purpose of this study was to investigate the effects of resin-based agents and aging on the color stability of ceramic veneers bonded to enamel. Material and methods Ceramic disks were cemented to bovine enamel disks with 4 resin-based luting agents (n=10): dual-polymerizing cement (RelyX ARC), light-polymerizing cement (RelyX Veneer), flowable composite resin (Filtek Z350 Flow), or composite resin preheated for 30 minutes at 60°C (Filtek Z350 XT). CIE L*, a*, and b* color coordinates were measured 24 hours after cementation (baseline) with a color spectrophotometer and reevaluated after 10 000 and 20 000 thermal cycles. Color variation was calculated by using CIELab (ΔE*ab ) and CIEDE2000 (ΔE00 ) methods. Then 95% confidence intervals were calculated for color variation means between baseline and 10 000 thermal cycles and between 10 000 and 20 000 thermal cycles. The 95% confidence intervals were also calculated for the means of individual color coordinates (L*, a*, and b*). Results The dual-polymerizing cement had the highest color variation among all luting agents. No significant differences were found in color variation among the light-polymerizing materials. All agents showed ΔE*ab >3.46 and ΔE00 >2.25 after 20 000 thermal cycles. Variations in L*, a*, and b* coordinates were material dependent. The dual-polymerizing agent was yellowish and reddish after aging. Conclusions The dual-polymerizing cement had higher color variation than the light-polymerized materials when used for bonding ceramic veneers to enamel. Flowable and preheated composite resins had similar color stability to that of light-polymerizing resin-based cement.