What kind of crown will not ever show a grey line at the gum line?

The grey line that some crowns show when a patients gums receed is usually from the metal substructure of porcelain fused to metal crowns. Although these crowns can be durable and are often a good choice in the posterior region, they are not the most esthetic for single crowns for anterior teeth.

Dentists can choose from a number of crowns that are metal free. In my New York dental practice I primarily use two types of crowns to acieve optimal esthetics in the anterior region. If strength is a priority I use Lava crowns. These crowns are good looking, have no tell tale gray metal margin and tend to be tough. They have a Zirconium core that supports the porcelain.

The best esthetics are achieved with all porcelain crowns that are bonded with composite luting cement. These can have the highest degree of translucency and are therefore the most 'life like'. They are more breakable than Lava crowns, but usually work well for anterior tooth restorations (in my experience).

Porcelain veneers can be a good option for many anterior teeth, since they leave most of the lingual tooth structure intact, but they need sufficient remaining enamel to bond to in order for them to work well. Also they are usually not as tough as the two types of crowns I mentioned. The sole exception would be a patient wtih a deep over bite. Often this type of bite puts a lot of pressure on the linguals of crowns and can cause breakage or loosening of a crown. Porcelain veneers work better for patients with these bites.