Objective To investigate the color difference between AuPt alloy porcelain and NiCr alloy porcelain.Methods 30 metalceramic specimens with different dentin porcelain thickness were fabricated with two types of metalceramic alloy, each type of alloy had 15 specimens. L\+*, a\+*, b\+* were measured after opaque porcelain was applied, and dentin porcelain was fired 1,3,5,7 times by MINOLTA CR100. Then △E was calculated which reflected the color difference between highgold alloy porcelain and NiCr alloy porcelain. Results Comparing with NiCr alloy porcelain, the color of AuPt alloy porcelain was reddish, yellowish and less bright. The △E between highgold alloy porcelain and NiCr alloy porcelain in shade A2 was largest when opaque porcelain was applied. It decreased when dentin porcelain was applied. It became smallest when fired 3 times, and increased along with the increase of fire times. It was larger than 1 5 except firing 3 times. When dentin porcelain was applied, △E which was larger than 1 5 among different dentin porcelain thickness decreased along with the increase of dentin porcelain thickness. Conclusion The color difference between the two types of metalceramic alloy should be carefully taken into account in order to improve the quality of color matching.
