Q. hi there im currently undergoing treatment of 3 crowns and a bridge all upper front teeth, my nhs dentist was going to fit porcelain fused with metal crowns at a cost of 1200 but after a bit of research i discovered the all porcelain crowns, now i have a choice the metal crowns at 1200 or the all porcalain at 2800, is there gonna be a big difference in appearance ? will the metal crowns end up discolouring? if so how long? thanks,