Cosmetic Dentistry Blog Cosmetic and General Dentistry Questions Answered

October 6, 2016

Metal present in dental ceramics


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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

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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.

July 9, 2016

Why does my crown keep falling off?


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Dr. Hall,
I have had a crown put on by a dentist and it was done same day. No temporary. Not sure what type of material he used for the crown. It fell out three times in less than a year. I went to a different dentist on the fourth time it fell out and he replaced the setting with a new one stating the other dentist didn’t create a good setting. This new crown is Zirconia Porcelain and it has fallen out twice in a month. He is suggesting a full porcelain crown on the same setting as he states the cement is adhering to my tooth but not the crown. He says the all porcelain has a more rough underside to adhere to the cement better. Any suggestions on what my next move should be?
– Stephanie from North Carolina

Stephanie,
Your same-day crown was a CEREC crown or a similar type that is milled by a computer in the dental office while you wait. But when properly prepared and bonded on, it will stay on permanently. It’s not the material your crown is made of. Gold crowns, porcelain crowns, CEREC crowns, zirconia crowns–all of them can be made to stay on solidly, permanently. I have most of those types of crowns in my own mouth and they stay on just fine.

There are two main factors for retention of a dental crown–the bonding strength of the cement, and the shape of the tooth preparation. Of those two, the shape of the tooth preparation is far more important. If the tooth is prepared with only a slight taper, a crown can be cemented with a very weak cement and it will still stay on. If it is prepared with a lot of taper, some of the strongest cements will not hold it on.

I’m not saying that getting a good bond between the crown and your tooth wouldn’t solve your problem. The strength of the cement is a factor. And I know very little about your tooth and the techniques these dentists used. But I do know that a tooth prepared with good retention form will not have a crown falling off three times in less than a year, regardless of the cement used. So even though I know very little about your tooth, I’m pretty confident that it was prepared with inadequate retention form.

So what should your next move be? I would find a dentist who knows how to do crowns that stay on. In 23 years of dental practice, I never had a crown fall off of any that I did for my patients, so I know it can be done.

For further understanding of this principle, of creating a crown that stays on, see my blog post from about nine months ago, “The main reason your crown probably fell off.”

I hope this is helpful.
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.

May 21, 2013

Fluoride in Supersmile toothpaste

Dr. Hall,
Does Supersmile toothpaste come without fluoride? My search was “do zirconia crowns stain” This site told me how to properly take care of my bridge. Happy I found this. Thank you for providing this information.
Susan from Arizona

Susan,
You’re right that Supersmile is a great product for keeping stains off teeth. However, all Supersmile products have a small amount of fluoride in them.

Fluoride is a naturally occurring mineral, and it’s virtually impossible to avoid ingesting it. When it is in toothpaste, the object is for it to bathe your teeth briefly in a small concentration of fluoride, which helps re-mineralize early decay spots. And then you rinse and spit. But otherwise, most natural well water has some fluoride in it, as well as canned juices and vegetables, soda, milk, and most other products that are liquids or that are processed with water. When I practiced in Iowa, we would sometimes have families come in from surrounding farms who drank well water. We would get samples of their well water and send it in for analysis. It always had some fluoride in it.

The efforts of dentists to encourage the use of fluoride is, to me, an evidence of the basic altruism of the profession. It does reduce tooth decay, which means less work for dentists. And while is is possible to get too much fluoride , in small amounts it is very healthy. It is of the same elemental family as table salt (sodium) and potassium. You can get too much sodium, but getting no sodium would be fatal. And the right amount of potassium is also essential to life, but if it is injected directly into a vein, it could stop your heart and kill you.

About your zirconia crowns or bridge – they should be very resistant to stain. Usually the core is made out of pure zirconia and it has a porcelain coating baked onto it. As long as the glaze on that porcelain is intact, it should resist almost any kind of stain. The advantage of Supersmile toothpaste is in its gentleness to the margin of the zirconia crown, which is a luting composite that would be vulnerable to stain and also to wear.
– 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.

April 11, 2013

Finding a cosmetic dentist in the Cayman Islands

Hi there Dr Hall,
Many thanks for such helpful information on your website. Your support is greatly appreciated! I currently reside in the Cayman Islands, my front right tooth slightly overlaps my front left tooth. Is there anyone you could recommend in Grand Cayman, so many cosmetic dentists I don’t know where to start. I have visited one, whom suggested getting all my teeth whitened, then 2 zirconia crowns on both front teeth as sister teeth. Are there any other options to compare, or does that sound wise. I am 34 with 2 young kids and finally want not to be too embarrassed to smile.

Many thanks
– Denise

Denise,
What you’re telling me about what this dentist wants to do makes me nervous. The idea that he or she wants to do zirconia crowns on these front teeth rather than bonded porcelain makes me think that he or she is not comfortable with bonded porcelain. Bonded porcelain would be preferable to zirconia. Zirconia is great for back teeth or bridgework, but I wouldn’t recommend it for an esthetically critical situation on your two front teeth. And I would think the ideal treatment would be porcelain veneers anyway, not crowns at all. Doing two or more crowns on front teeth can put you at risk of breaking them off from lateral stresses.

I don’t understand all these cosmetic dentists you are talking about. I just googled cosmetic dentists in the Cayman Islands and looked at several websites and couldn’t find anyone I would trust with even the simplest cosmetic procedures, much less something as involved as what you are telling me. Even in the United States, fewer than one dentist out of fifty could do a beautiful job on your case. I would be surprised if you could find a dentist in the entire Caribbean area who could do a nice job on this. Quite frankly, I would fly in to Miami and have someone there do this. Dr. Sam Sadati near West Palm Beach is one I know personally who would do beautiful work for you. You could have your teeth whitened there locally and then get the two veneers or whatever your case requires done in Florida.

Why spend money to give you a mediocre cosmetic result and then possibly end up with damaged front teeth besides? Spend a little extra for a couple of trips to Florida and get it done right.
Dr. Hall

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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.

November 23, 2009

My cosmetic dentist wants to use Zirconia crowns

Dear Dr. Hall
To find an accredited cosmetic dentist I used your website. The dentist was not aware of using bonded all porcelain crowns for front teeth, the accredited cosmetic dentist relied on the advice of the lab tech. The lab tech refused to use bonded all porcelain on front crowns (upper)and insisted the dentist use Zirconia. Who is more knowledgeable or experienced in accredited cosmetic dentistry, the lab tech or the dentist? Thanking you in advance for your prompt reply.
Gina from Connecticut

Gina,
I’m not sure I understand what you’re saying.

Are you saying that you went to a dentist that we recommended on mynewsmile.com, and that this dentist had not heard of bonded, all–porcelain crowns for front teeth?

If so, I’d like to know, and I’d like to know which dentist that was.
And how was it that the lab tech was asked?

l want to try to figure out what happened with your case and then see if I can help you.

Thanks,
Dr. Hall

Dr. Hall
When I mentioned to Dr. N. Summer Lerch of New Haven,CT that I was looking for an accredited cosmetic dentist that would be skilled in bonded all– porcelain crowns for front teeth. Dr. Lerch did not confirm or acknowledge your findings that bonded all-porcelain crowns for front teeth would have the strength that Zirconia would have. Dr. Lerch relied on the lab tech’s recommendations for the crowns. Actually the lab tech refused to make the crowns in stackable porcelain. Unable to find another dentist at that time because I was charged in full for payment of my crowns on the day the lab tech refused to use stackable porcelain on front crowns.
If all this is confusing I will include my home phone if you have questions.
Thanks
Gina

Gina,
Zirconia crowns ARE stronger than bonded all porcelain. They have no metal, and while they are not all-porcelain, I would call them all-ceramic, and their appearance is excellent. They can be made beautifully translucent. A conventional porcelain is usually baked over the zirconia framework, and the end result can be made to look so natural that you could not tell them from natural teeth.

I don’t believe that your dentist was unaware of bonded all-porcelain, but rather than for your situation she felt that zirconia would work better. I’m not in a position to second guess that recommendation, not being able to examine you.

Which particular crowns should be used in a given situation is a matter that depends on a number of factors. I don’t recommend that patients try to push their dentist into using a particular type of crown, because often part of the decision is based on what works well in the hands of a particular dentist, and this will vary from dentist to dentist. Rather, I recommend that each patient find a dentist whom they trust and has the skills necessary to produce a beautiful result, and then give that dentist free rein to choose the material that works best for them in each particular situation.

Dr. Lerch was carefully considered before I recommended her on this website, and I am absolutely confident that she could produce a beautiful result for you. She has been on the accreditation examining board, which means that her esthetic talent and technical ability are highly regarded among her peers.

As far as relying on information from the lab tech, when a dentist has a trusting relationship with a skilled laboratory technician, yes, we often use them as a source of information on new materials. Zirconia is an up-and-coming material that many top cosmetic dentists are turning to, because it is so strong and can be made highly esthetic. And when it comes to the technical information about the strength of the material and its suitability for various situations, then yes, we will turn to the technician. I have criticized on this blog dentists who use the laboratory technician for a shade-matching appointment, because an excellent cosmetic dentist needs to have a great eye for color and an ability to communicate color. But the dentist and the technician are a team and each brings expertise and talent to every project.

I’m skeptical that the laboratory technician made the final decision in your case. If you were giving me trouble over my choice of material, I might use the lab tech’s opinion to help avoid arguing with you. When we as dentists are faced with a difficult patient who wants to push us into a treatment we know will be sub-standard, it’s easy for us to say things that may seem to that patient to be unreasonable. I’m inclined to believe that Dr. Lerch was showing integrity in your case, but I can see how it wouldn’t appear that way to you.
Dr. Hall

Related information:
Read more about porcelain crowns.
Click here to find an expert cosmetic dentist.

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.

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