Metal-free all-porcelain crowns are used on severely damaged or previously prepared teeth to improve both appearance and oral health. We do not prepare any teeth for this procedure that have not already been reduced for a previous crown. Preserving healthy tooth structure should be one of the most important principles of dentistry, based on current knowledge.
Although many factors influence the appearance of crowns, the most important one is how they respond to light. Natural teeth allow light to pass through them. As a result, the teeth appear to have depth and vitality. Because metal-free porcelain crowns (all-porcelain) are translucent, they exhibit greater depth and vitality, thereby producing results that most closely resemble natural teeth.
Since all-porcelain crowns allow light to pass through, they create an aesthetic appearance very similar to that of natural teeth, whereas metal-porcelain crowns even when very well made have a dull and artificial appearance. For this reason, all-porcelain crowns are preferred, especially for front teeth.
Metal-supported porcelain crowns can create the appearance of a dark gap in the mouth under certain lighting conditions, as if they weren’t there. All-porcelain restorations, on the other hand, transmit light just like natural teeth. Metal-supported porcelain restorations are mechanically bonded to the tooth. All-porcelain restorations, however, are bonded to the tooth both mechanically and chemically. For this reason, their retention is much higher than that of metal-supported restorations.
Since there is no metal in the substructure, there is no dark line at the crown-gum junction. This results in a more aesthetic appearance. When the gums recede, all-porcelain crowns maintain their aesthetic appearance, whereas metal-porcelain crowns create an unsightly appearance at the junction with the tooth. The risk of an allergic reaction to certain metals used in the substructure (such as nickel) does not exist with all-porcelain crowns.
