Dentistry has been practiced for over 4,600 years. The earliest known reference to a dentist is that of an Egyptian scribe known as Hesy-Re who has an inscription on his tomb that reads “the greatest of those who deal with teeth, and of physicians.” Some of the earliest crowns were gold crowns made by the Etruscans around 166 AD of the Tuscany area from what is now Italy.
In modern times, the gold crown is often considered the strongest, most durable and almost indestructible restoration possible in dentistry. Even many esthetically oriented dentists appreciate the value of using gold crowns for restoring the second molars in the human dentition. This is because the second molars experience the most force out of all of our teeth (assuming there are no wisdom teeth present). The reason for this is that our jaws functions like a class two lever system. The TMJ (temperomandibular joint) is the fulcrum and the closer you go toward this fulcrum, the more force is experienced. Our jaw resembles a nutcracker in this way. When you want to break the nut (or bite through the hard food) you place it as far back as possible, as close to the fulcrum (TM joint) as possible. Gold crowns have no porcelain that can chip off or crack under the heavy forces in the back of our mouths. In addition, gold does not corrode as easily as other metals do in moist environments. Any dental student will tell you that the dental restorations that have proven to last the longest are the ones made of gold. I have personally seen some over 70 years old in patient’s mouths looking as nice and clinically sound as the day they were placed.
However, gold is not very acceptable in today’s society from an esthetic perspective. If a restoration will show when a patient smiles, there are nicer looking materials to choose from today. In the 1960’s acrylic veneer crowns were more popular. Acrylic was used to mechanically engage the gold and thus veneer the metal substructure of a crown. The drawback was that the acrylic would rapidly wear away after years of chewing since it was a much softer material than the natural enamel teeth it was chewing against.
In the 1970’s porcelain veneer crowns became more popular due to the increased hardness and better translucency and luster of porcelain compared to acrylic. This type of crown had the benefit of the nicer esthetic qualities and hardness of porcelain along with the strength and durability of the metal substructure. Porcelain veneer crowns, sometimes called porcelain fused to metal crowns (pfm’s) are still one of the strongest and nicest restorations available when fracture resistance is important. They have the big advantage of allowing metal to be used on the inner surface (in order not to wear down the opposing lower teeth as quickly over the years) while using porcelain on the outside for a beautiful lifelike translucency when made correctly.
The latest crown innovations are all porcelain crowns made of lithium disilicate or Zirconium and pressed ceramics. Crowns made of each of these materials have advantages and disadvantages when compared to the porcelain fused to metal crowns. All of these kinds of crowns allow some increased translucency, which resembles what occurs with natural teeth in the mouth. There is no metal substructure to block the light internally underneath the porcelain with the exception of the Zirconium which is white but opaque. Pressed ceramic and lithium disilicate are the more translucent materials allowing for a more natural appearance of the crown.
All of these materials require different amounts and locations of tooth preparation to allow for adequate thickness of the restorative materials. It is important to take into account the way the opposing teeth fit together with the teeth to be crowned. If the patient has a deep overbite, all porcelain crowns may not be possible due to less than ideal room for the required thickness of the material. In addition, teeth that are already narrow or have had root canals may be too weak to withstand the deeper preparations required for all porcelain crown systems. These situations require the expertise of an experienced dentist to find the best alternative to achieve maximum esthetics with maximum strength.
At Springs Dental, I carefully evaluate the clearance when the patient bites together as well as the history of the tooth and the patient’s esthetic concerns before deciding what kind of crown to use. As a dentist with over 25 years of experience in dentistry in Saratoga Springs, NY I am dedicated to putting our patients first and recommending the best approach to satisfy their esthetic and functional needs to achieve comfortable chewing and a beautiful smile.