Excellent porcelain veneers dental services London: Porcelain-fused-to-metal crowns: These implants are a hybrid between porcelain and metal. They have a metal base and are covered with a layer of porcelain. They are more durable than porcelain crowns but have a more natural appearance than metal crowns. However, they look less natural than porcelain teeth, and over time they can develop a dark line around the gum. Like metal implants, they can cause tooth sensitivity. Crowns are usually placed over two visits. During the first visit, the tooth is prepared by removing a layer of enamel. You will usually be given …