While the dental crowns of the past were often made of gold or metal alloys, for more than a century, dentists have been using porcelain to craft more lifelike-looking crowns. While porcelain more closely resembles the natural teeth than metal, however, it’s not as strong, making it less than ideal at withstanding the natural forces of everyday activity like eating and laughing. In the 1950s, dentists began using porcelain fused to a metal base to make crowns that combine the durability of metal with the appearance of porcelain; while these types of crowns are an improvement over metal crowns in terms of aesthetics, the metal core can diminish the luster of its porcelain casing and may be fully visible at the base of the crown, closer to the gum line. In the early 2000s, the introduction of zirconia dental crowns offered an option that combines the strength of metal with the appearance of porcelain without involving any metal at all, and since their introduction, the appearance and functionality of zirconia crowns has only continued to improve. In some cases, patients may choose crowns made of gold or metal alloys, though the majority of dental crowns in the present day are made of either porcelain, porcelain fused to metal, or zirconia – and, as zirconia continues to provide results that are both structurally and aesthetically, superior, it continues to grow in popularity.
Zirconia is made from zirconium, a metal in the same family as titanium, though zirconia does not appear metallic. This metal oxide is highly translucent and similar in appearance to the luster of dental enamel, yet it is strong and durable like metals are. Because of its strength, it’s particularly appealing for patients who need dental crowns in the rear of the mouth where the teeth are exposed to greater force from chewing but can still be seen when the mouth is open. Porcelain crowns are made of porcelain, which looks like natural teeth but is more porous and prone to breakage than metal and zirconia. Crowns that are porcelain fused to metal use porcelain overlays, dyed to match the natural teeth, fixed over metal crowns. While these types of crowns deliver strength and a lifelike appearance, it’s possible for the dark metal base to show through closer to the gum line, especially if the gums start to recede, and some patients report that the metal base can lend a grayish tinge to their crown. Porcelain fused to metal crowns may be recommended for patients who want dental crowns that combine the strength of metal and the appearance of porcelain.
Because of the superlative strength and natural appearance of zirconia crowns, more and more people have been selecting zirconia when it’s provided as an option. Zirconia crowns are easily customizable, durable, and reliable, demonstrating high success rates over time. Zirconia is two to three times stronger than porcelain and porcelain fused to metal, withstanding the forces of biting and chewing without chipping or breaking. Because there is no metal base for a zirconia crown, there is no risk of metal appearing at the base of a crown, and these crowns can easily be modified and positioned to match the size and shape of the adjacent natural teeth in most situations and with little margin of error. Zirconia may also be preferable for patients who are allergic to metal and metal alloys, or for people who simply prefer to not have metal in their dental restorations, as the material is highly biocompatible and clinically safe. While many patients still choose porcelain and porcelain fused to metal, zirconia is fast becoming the preferred choice for strong, lifelike dental crowns.