Cosmetic Dentistry Blog Cosmetic and General Dentistry Questions Answered

March 7, 2019

All ceramic vs porcelain-fused-to-gold crowns


We thank our advertisers who help fund this site.

Dr. Hall
I am having crowns replaced over tooth number 4 & 5. There is, as I believe, no cosmetic value of using pure porcelain versus Crown Porcelain fused to High Noble. There is a significant extra cost of $200.00 per each pure porcelain. In general, would a pure porcelain fused to a High Noble versus pure porcelain be just as effective over the long term?
– Garry from California

Garry,
First, I like to talk about terminology so we know exactly what we are talking about. We should be saying all-ceramic crowns, not all-porcelain. Porcelain is only one of various ceramics that have been used for crowns and even some dentists gloss over this terminology. Few dentists are placing all-porcelain crowns on back teeth these days because they are very technique sensitive and are much weaker than the newer high-strength ceramics, lithium disilicate and zirconia. The eMax crown, which I believe is the most popular crown being used by dentists today, features a lithium disilicate core with porcelain baked over it. Lithium disilicate has reasonable aesthetics—it is white and somewhat translucent—but it comes in blocks and is shaped by milling, so the technician doesn’t have the ability to manipulate the color the way porcelain color is manipulated. Porcelain comes in a paste and it is placed, shaped, and then baked. So the ceramist can apply various colors and translucencies of the paste in different layers over the lithium disilicate core with a great deal of control over the aesthetics.

My guess would be that your dentist is talking about putting all-ceramic crowns on your teeth numbers 4 and 5, which are the first and second premolars on your upper right. So your question is, should you get porcelain fused to high noble (otherwise called porcelain fused to gold) instead.

Cosmetic dentists consider upper first premolars to be in the smile zone on almost all patients. Practically everyone will show that first premolar prominently when they smile. It may not be prominent when you look at yourself straight on in the mirror, but it is very noticeable from the side. For me, I would not want a crown made of porcelain fused to gold or any other metal here because there will be a significant risk of a dark line showing at the gumline. The dark line comes from the metal foundation showing through right at the margin of the crown.

Behind that first premolar, in my smile, the teeth are all in the shadows, so the aesthetics is much less critical there. In my mouth, I do have a porcelain fused to gold crown on one of those teeth. I also have a crown on my upper left first premolar, and that crown is an eMax.

So my answer is that I disagree that there is no cosmetic value here. Having said that, if you were my patient and wanted the porcelain fused to gold crown on your first premolar, I wouldn’t fight you on that. But then I probably wouldn’t have the issue come up because I would charge the same fee for either crown. A porcelain fused to high noble crown is a premium crown, and I charged more for that than for a porcelain fused to noble (semi-precious metal) crown. But I don’t understand why the all-ceramic crown needs to be more than the porcelain fused to high noble.

– Dr. Hall

Do you have a comment or anything else to add? We’d love to hear from you. Enter your comment below.

Click here to ask Dr. Hall a question of your own.

About David A. Hall

Dr. David Hall was one of the first 40 accredited cosmetic dentists in the world. He practiced cosmetic dentistry in Iowa, and in 1990 earned his accreditation with the American Academy of Cosmetic Dentistry. He is now president of Infinity Dental Web, a company in Mesa, Arizona that does complete Internet marketing for dentists.

October 6, 2016

Metal present in dental ceramics


We thank our advertisers who help fund this site.

Hi Dr. Hall,
I like your website–it is informative.
I am a naturopath and need a crown. I’m concerned over some of the materials used. After my research, so I far like the look of the ceramic crowns (is this glass?) and wondering what Vita ceramic is made out of. I’m finding it hard to get an answer. I basically don’t want any with metals or lithium as I have thyroid issues.
Thank you,
Vanessa from New Zealand

Vanessa,
Any crown that is all ceramic is not going to have any metal in it. But I’m reading between the lines of your question, and I think you are asking about avoiding any metal ions in the crown. I don’t believe this is going to be possible to do, as there are metal ions in every dental ceramic I am aware of.

Let’s get into a little chemistry. Iron is a metal. Rust is iron combined with oxygen–iron oxide. While rust isn’t a metal, it has metal ions in it. And while you wouldn’t want to eat metallic iron, of course, iron ions are essential to life. They’re an important ingredient of our diet, since the hemoglobin in our blood has iron ions in it. The iron in our blood is what gives blood its red color.

Similarly, sodium is a metal. As a pure metal, it is toxic, but combined as a metal ion with chlorine it is sodium chloride, or common table salt, and is also essential to life.

Other metal ions that are important ingredients in our diet include calcium, potassium, magnesium, zinc, copper, manganese, molybdenum, and cobalt.

Lithium is a metal that is in the same family as sodium. It is so reactive that it doesn’t occur freely in nature, so it is found naturally in its ionic form combined with other elements. Lithium disilicate is a ceramic that is very strong and has been developed in the past few years to be used in dental crowns. I have in my mouth an e.max crown, which is made of lithium disilicate.

Zirconium is another metal. Combined in its ionic form with oxygen, it is known as zirconia, and is a ceramic that is even stronger than lithium disilicate and has also been developed recently to be used in dental crowns. It is so strong that it can be used in bridges without requiring a metal framework, something that is very risky with other ceramics.

You mention Vita. Vita is a brand of porcelain. Porcelain is a conventional ceramic that has been used for many years for dental crowns. It isn’t very strong by itself, but when it is bonded to tooth structure, it is strong enough for crowns on front teeth and premolars. Dental porcelains are made with kaolin as a key ingredient. Kaolin is a clay that has silica and aluminum oxide. Aluminum again is a metal, but it isn’t aluminum metal that is in these crowns but aluminum ions.

Glass is pure silica (silicon dioxide). Silicon is not a metal, but glass isn’t strong enough to be used as a crown, though there are some crowns that use a layer of glass on the outside (Empress crowns). However, the glass they use in Empress crowns is a leucite glass that has aluminum tectosilicate in it.

So you can take all of this information and figure out what you want to do. I am not aware of any biocompatibility issues with any of these ceramics. However, if you were to ask me my opinion about which one would be least likely to provoke any biological reaction, I would say the zirconia.

– Dr. Hall

Do you have a comment or a question or anything else to add? We’d love to hear from you. Enter your comment below.

Click here to ask Dr. Hall a question of your own.

About David A. Hall

Dr. David Hall was one of the first 40 accredited cosmetic dentists in the world. He practiced cosmetic dentistry in Iowa, and in 1990 earned his accreditation with the American Academy of Cosmetic Dentistry. He is now president of Infinity Dental Web, a company in Mesa, Arizona that does complete Internet marketing for dentists.

April 4, 2012

What treatment is needed for a calcified root canal?

Hi Dr Hall,
First of all I appreciate the good work that you are doing.
Regarding my question: my daughter had yellow staining on her right front tooth. The doc did an x-ray and said the root canal is getting calcified and suggested a root canal. After the root canal we suggested to leave it as such but he said the tooth would fracture and a crown is a must. The crown he suggested was LAVA. We were not happy with the finish so we are trying an e.max or perhaps a metal-free ceramic. To push us to decide fast he frightened us that the gums are falling down. But I am happy I did not go with a badly made crown. I would like to know whether I have been taken for a ride and two which is the best crown to use? My gratitude for your enlightening blog I shall recommend to all my colleagues. My prayers and God Bless
– Bransdon from India

Bransdon,
I’m glad to be able to help.

First of all, I’m not sure why your daughter needs a root canal on this tooth. Just because the canal is getting calcified? As long as it’s not infected, she doesn’t need a root canal treatment. Calcification of a root canal is just the depositing of extra dentin inside the tooth. It  can happen after a traumatic injury – it’s the tooth’s attempt to protect itself against infection of the canal. Also, all teeth tend to have their canals get a little calcified as we get older.

Second, even if she has a root canal treatment, she doesn’t necessarily need a crown on this front tooth. While a back tooth that has had a root canal treatment will be prone to fracture if it doesn’t have a crown, a crown on a front tooth with a root canal treatment will weaken the neck of the tooth. A back tooth has a chewing surface. Chewing pressure on this surface will tend to push apart the cusps of the tooth, possibly causing it to split. But if a front tooth breaks, it tends to break around the neck of the tooth, and it just breaks off entirely at that point rather than splitting as back teeth do.

The Lava crown and the e.max crown are very similar to each other. They both have a very strong lithium disilicate base overlaid with a feldspathic porcelain, but they are made by different companies. They are a good crown for dentists who aren’t very good at cosmetic dentistry procedures, but they require aggressive tooth reduction, which will further weaken this tooth.

In India, you have to be very careful with getting crowns or any type of complicated dental care. I’m not all that familiar with their standards there, but I know they aren’t as high as they are here in the United States. But the best thing to do for a front tooth that does not have a large filling, which sounds like it is your daughter’s situation, is, after the root canal treatment (if it needs that), to then have a translucent fiberglass post placed to strengthen the tooth. Before placing the post, all of the root canal cement and root canal filling materials should be cleaned out from the inside of the visible part of the tooth – this will help insure against discoloration. If the color is off, I would have that fixed with a thin porcelain veneer. That will help the tooth retain its maximum strength. And I would try to seek out a dentist who is somewhat familiar with cosmetic dentistry procedures. There are dentists in India who are members of the American Academy of Cosmetic Dentistry, and I would seek out one of those. (You can go to the AACD website and pull up a membership list.)

I do not recommend, in the United States, relying on membership in the AACD for any type of assurance that a dentist will do good cosmetic dental work. But in India, it does show a strong level of commitment to cosmetic dentistry to be willing to fly to the United States to learn these procedures.

– Dr. Hall

We thank our advertisers who help fund this site.

About David A. Hall

Dr. David Hall was one of the first 40 accredited cosmetic dentists in the world. He practiced cosmetic dentistry in Iowa, and in 1990 earned his accreditation with the American Academy of Cosmetic Dentistry. He is now president of Infinity Dental Web, a company in Mesa, Arizona that does complete Internet marketing for dentists.

Powered by WordPress

Follow this blog

Get every new post delivered right to your inbox.


Categories